• The De Sitter Challenge - Has to be answered

    From gehan.ameresekere@gmail.com@21:1/5 to All on Sun Apr 30 23:10:12 2023
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star orbiting in a double-star system would usually, with regard to us, alternate between moving towards us and away from us. Light emitted from different parts of the orbital path would travel
    towards us at different speeds. For a nearby star with a small orbital velocity (or whose orbital plane was almost perpendicular to our line of view) this might merely make the star's orbit seem erratic, but for a sufficient combination of orbital speed
    and distance (and inclination), the "fast" light given off during approach would be able to catch up with and even overtake "slow" light emitted earlier during a recessional part of the star's orbit, and the star would present an image that was scrambled
    and out of sequence. That is, Kepler's laws of motion would apparently be violated for a distant observer."

    Question: If light travels from the star at velocity c relative to the Earth, at what relative velocity does it have relative to the surface of the star, when viewed from the reference frame in which the Earth?

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  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Mon May 1 19:36:34 2023
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us,
    alternate between moving towards us and away from us. Light emitted
    from different parts of the orbital path would travel towards us at
    different speeds. For a nearby star with a small orbital velocity (or
    whose orbital plane was almost perpendicular to our line of view)
    this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be
    able to catch up with and even overtake "slow" light emitted earlier
    during a recessional part of the star's orbit, and the star would
    present an image that was scrambled and out of sequence. That is,
    Kepler's laws of motion would apparently be violated for a distant
    observer."

    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?

    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    This does not contradict the constancy of the speed of light, which
    relates to the speed as measured by an observer, not the speed of light relative to anything else.

    Of course, for an observer on the star, the light is observed to depart
    at speed c.

    Sylvia.

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  • From Paul B. Andersen@21:1/5 to All on Mon May 1 12:41:47 2023
    Den 01.05.2023 08:10, skrev gehan.am...@gmail.com:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star orbiting in a double-star system would usually, with regard to us, alternate between moving towards us and away from us. Light emitted from different parts of the orbital path would travel
    towards us at different speeds. For a nearby star with a small orbital velocity (or whose orbital plane was almost perpendicular to our line of view) this might merely make the star's orbit seem erratic, but for a sufficient combination of orbital speed
    and distance (and inclination), the "fast" light given off during approach would be able to catch up with and even overtake "slow" light emitted earlier during a recessional part of the star's orbit, and the star would present an image that was scrambled
    and out of sequence. That is, Kepler's laws of motion would apparently be violated for a distant observer."

    Question: If light travels from the star at velocity c relative to the Earth, at what relative velocity does it have relative to the surface of the star, when viewed from the reference frame in which the Earth?

    Don't you see that your question is meaningless?

    The speed of light is c relative to the surface of the star.
    Which means that the speed of light is c when measured
    in the rest frame of the star.

    The speed of light is c relative to the Earth.
    Which means that the speed of light is c when measured
    in the rest frame of the Earth.

    You are asking:
    What is the speed of light measured in the rest frame of
    the star when measured in the rest frame of the Earth.

    --
    Paul

    https://paulba.no/

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  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Mon May 1 05:05:05 2023
    On Monday, May 1, 2023 at 2:36:38 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us, alternate between moving towards us and away from us. Light emitted
    from different parts of the orbital path would travel towards us at different speeds. For a nearby star with a small orbital velocity (or whose orbital plane was almost perpendicular to our line of view)
    this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be
    able to catch up with and even overtake "slow" light emitted earlier during a recessional part of the star's orbit, and the star would
    present an image that was scrambled and out of sequence. That is,
    Kepler's laws of motion would apparently be violated for a distant observer."

    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?
    If the star is moving towards the Earth at velocity v, then in the Earth frame the light is moving at velocity (c - v) relative to the star.

    This does not contradict the constancy of the speed of light, which
    relates to the speed as measured by an observer, not the speed of light relative to anything else.

    Of course, for an observer on the star, the light is observed to depart
    at speed c.

    Sylvia.

    If the star is moving towards the Earth at velocity v, then in the Earth frame the light is moving at velocity (c - v) relative to the star.

    If this is true, then have a look at this scenario.

    c

    X

    c

    In the Earth's frame of reference, light travels at c relative to the Earth. That means the relative velocity between the light and the surface of the star is c-v in the bottom case, where the star is approaching the Earth.

    When the same star is moving away from the Earth, we have the relative velocity between light or a particular photon or group of photons moving at c+v relative to the surface of the star.

    You can call this closing speed or relative speed.

    The fact is that the light is emitted at a different relative velocity relative to the surface of the star depending on the direction it is travelling - towards the Earth or away.

    Doesn't this violate the 'First Postulate'?

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  • From gehan.ameresekere@gmail.com@21:1/5 to Paul B. Andersen on Mon May 1 05:05:25 2023
    On Monday, May 1, 2023 at 3:41:54 PM UTC+5, Paul B. Andersen wrote:
    Den 01.05.2023 08:10, skrev gehan.am...@gmail.com:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star orbiting in a double-star system would usually, with regard to us, alternate between moving towards us and away from us. Light emitted from different parts of the orbital path would
    travel towards us at different speeds. For a nearby star with a small orbital velocity (or whose orbital plane was almost perpendicular to our line of view) this might merely make the star's orbit seem erratic, but for a sufficient combination of orbital
    speed and distance (and inclination), the "fast" light given off during approach would be able to catch up with and even overtake "slow" light emitted earlier during a recessional part of the star's orbit, and the star would present an image that was
    scrambled and out of sequence. That is, Kepler's laws of motion would apparently be violated for a distant observer."

    Question: If light travels from the star at velocity c relative to the Earth, at what relative velocity does it have relative to the surface of the star, when viewed from the reference frame in which the Earth?
    Don't you see that your question is meaningless?

    The speed of light is c relative to the surface of the star.
    Which means that the speed of light is c when measured
    in the rest frame of the star.

    The speed of light is c relative to the Earth.
    Which means that the speed of light is c when measured
    in the rest frame of the Earth.

    You are asking:
    What is the speed of light measured in the rest frame of
    the star when measured in the rest frame of the Earth.

    --
    Paul

    https://paulba.no/

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  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Mon May 1 23:06:38 2023
    On 01-May-23 10:05 pm, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 2:36:38 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us,
    alternate between moving towards us and away from us. Light emitted
    from different parts of the orbital path would travel towards us at
    different speeds. For a nearby star with a small orbital velocity (or
    whose orbital plane was almost perpendicular to our line of view)
    this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be
    able to catch up with and even overtake "slow" light emitted earlier
    during a recessional part of the star's orbit, and the star would
    present an image that was scrambled and out of sequence. That is,
    Kepler's laws of motion would apparently be violated for a distant
    observer."

    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?
    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    This does not contradict the constancy of the speed of light, which
    relates to the speed as measured by an observer, not the speed of light
    relative to anything else.

    Of course, for an observer on the star, the light is observed to depart
    at speed c.

    Sylvia.

    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    If this is true, then have a look at this scenario.

    c

    X

    c

    In the Earth's frame of reference, light travels at c relative to the Earth. That means the relative velocity between the light and the surface of the star is c-v in the bottom case, where the star is approaching the Earth.

    When the same star is moving away from the Earth, we have the relative velocity between light or a particular photon or group of photons moving at c+v relative to the surface of the star.

    You can call this closing speed or relative speed.

    The fact is that the light is emitted at a different relative velocity relative to the surface of the star depending on the direction it is travelling - towards the Earth or away.

    If the observer on Earth seeks to calculate the speed that an observer
    on the star sees the light emitted, they must use the velocity
    composition formula. If the star is moving towards the Earth at velocity
    v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.

    That is, in the frame of a observer on the star, the light is emitted at velocity c.

    The same applies if the star is moving away from the Earth.

    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any
    contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.


    Doesn't this violate the 'First Postulate'?

    Clearly, not.

    Sylvia.

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  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Mon May 1 18:02:01 2023
    On Monday, May 1, 2023 at 6:06:43 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 10:05 pm, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 2:36:38 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us,
    alternate between moving towards us and away from us. Light emitted
    from different parts of the orbital path would travel towards us at
    different speeds. For a nearby star with a small orbital velocity (or >>> whose orbital plane was almost perpendicular to our line of view)
    this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be
    able to catch up with and even overtake "slow" light emitted earlier
    during a recessional part of the star's orbit, and the star would
    present an image that was scrambled and out of sequence. That is,
    Kepler's laws of motion would apparently be violated for a distant
    observer."

    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?
    If the star is moving towards the Earth at velocity v, then in the Earth >> frame the light is moving at velocity (c - v) relative to the star.

    This does not contradict the constancy of the speed of light, which
    relates to the speed as measured by an observer, not the speed of light >> relative to anything else.

    Of course, for an observer on the star, the light is observed to depart >> at speed c.

    Sylvia.

    If the star is moving towards the Earth at velocity v, then in the Earth >> frame the light is moving at velocity (c - v) relative to the star.

    If this is true, then have a look at this scenario.

    c

    X

    c

    In the Earth's frame of reference, light travels at c relative to the Earth. That means the relative velocity between the light and the surface of the star is c-v in the bottom case, where the star is approaching the Earth.

    When the same star is moving away from the Earth, we have the relative velocity between light or a particular photon or group of photons moving at c+v relative to the surface of the star.

    You can call this closing speed or relative speed.

    The fact is that the light is emitted at a different relative velocity relative to the surface of the star depending on the direction it is travelling - towards the Earth or away.
    If the observer on Earth seeks to calculate the speed that an observer
    on the star sees the light emitted, they must use the velocity
    composition formula. If the star is moving towards the Earth at velocity
    v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.

    That is, in the frame of a observer on the star, the light is emitted at velocity c.

    The same applies if the star is moving away from the Earth.

    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any
    contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.

    Doesn't this violate the 'First Postulate'?
    Clearly, not.

    Sylvia.

    The initial objection to the ballistic theory of light came from the results of the De Sitter experiment under Newtonian physics.
    If the ballistic theory was correct, and this is under Newtonian Physics, then the results would have been different, as the story goes.

    According to the ballistic theory, the velocity of emission of light relative to the source is constant. Since this was proved to be wrong by the experiment, as it is said, then the velocity of emission of light is not constant relative to the source.
    More than that, the velocity of emission of light relative to the surface is different depending on the position of the Earth.

    To meet your objections:

    If the observer on Earth seeks to calculate the speed that an observer
    on the star sees the light emitted, they must use the velocity
    composition formula. If the star is moving towards the Earth at velocity
    v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.

    The same applies if the star is moving away from the Earth.

    Are you saying the same formula applies for when the star is moving away from the Earth?
    In that case v1 <> v2 so will we get the same result, or do we have to apply a formula with different signs depending
    on the direction the start is moving, to or away from the Earth?

    I thought the velocity of the source does not matter, v can be taken to be +1, -10000, 0r 0.
    Is this the meaning of independent of the 'motion of the source'?

    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any
    contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.

    I am not attempting to determine the velocity of emission. I am simply asking what the rule for velocity of emission from
    the surface of a star is.

    Your answer:

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  • From patdolan@21:1/5 to gehan.am...@gmail.com on Mon May 1 18:19:52 2023
    On Monday, May 1, 2023 at 6:02:03 PM UTC-7, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 6:06:43 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 10:05 pm, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 2:36:38 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us,
    alternate between moving towards us and away from us. Light emitted >>> from different parts of the orbital path would travel towards us at >>> different speeds. For a nearby star with a small orbital velocity (or >>> whose orbital plane was almost perpendicular to our line of view)
    this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be
    able to catch up with and even overtake "slow" light emitted earlier >>> during a recessional part of the star's orbit, and the star would
    present an image that was scrambled and out of sequence. That is,
    Kepler's laws of motion would apparently be violated for a distant
    observer."

    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?
    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    This does not contradict the constancy of the speed of light, which
    relates to the speed as measured by an observer, not the speed of light >> relative to anything else.

    Of course, for an observer on the star, the light is observed to depart >> at speed c.

    Sylvia.

    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    If this is true, then have a look at this scenario.

    c

    X

    c

    In the Earth's frame of reference, light travels at c relative to the Earth. That means the relative velocity between the light and the surface of the star is c-v in the bottom case, where the star is approaching the Earth.

    When the same star is moving away from the Earth, we have the relative velocity between light or a particular photon or group of photons moving at c+v relative to the surface of the star.

    You can call this closing speed or relative speed.

    The fact is that the light is emitted at a different relative velocity relative to the surface of the star depending on the direction it is travelling - towards the Earth or away.
    If the observer on Earth seeks to calculate the speed that an observer
    on the star sees the light emitted, they must use the velocity
    composition formula. If the star is moving towards the Earth at velocity v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.

    That is, in the frame of a observer on the star, the light is emitted at velocity c.

    The same applies if the star is moving away from the Earth.

    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.

    Doesn't this violate the 'First Postulate'?
    Clearly, not.

    Sylvia.
    The initial objection to the ballistic theory of light came from the results of the De Sitter experiment under Newtonian physics.
    If the ballistic theory was correct, and this is under Newtonian Physics, then the results would have been different, as the story goes.

    According to the ballistic theory, the velocity of emission of light relative to the source is constant. Since this was proved to be wrong by the experiment, as it is said, then the velocity of emission of light is not constant relative to the source.
    More than that, the velocity of emission of light relative to the surface is different depending on the position of the Earth.

    To meet your objections:
    If the observer on Earth seeks to calculate the speed that an observer
    on the star sees the light emitted, they must use the velocity
    composition formula. If the star is moving towards the Earth at velocity v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.
    The same applies if the star is moving away from the Earth.
    Are you saying the same formula applies for when the star is moving away from the Earth?
    In that case v1 <> v2 so will we get the same result, or do we have to apply a formula with different signs depending
    on the direction the start is moving, to or away from the Earth?

    I thought the velocity of the source does not matter, v can be taken to be +1, -10000, 0r 0.
    Is this the meaning of independent of the 'motion of the source'?
    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.
    I am not attempting to determine the velocity of emission. I am simply asking what the rule for velocity of emission from
    the surface of a star is.

    Your answer:
    gahan, may I offer some advice when arguing relativity. Let me give you two sure-fire, tried-and-true debating strategies to permanently silence the Sylvias and Paul B. Andersons of this forum.

    1) Subject SR to planetary motion. Planetary motion falsified SR almost immediately after it was propounded by Einstein. Einstein's response to this falsification was to jettison gravity as the reason for planetary motion and invent a new reason for
    planetary motion; namely, GR. But GR doesn't rescue SR from falsification. Please check out to the Eponymous Dilemma in this regard.

    2) Never argue the algebra of SR. It is consistent. But only as long as the relativists get to define the premises/terms used in the LTs. The premise/term you want to challenge is v. The v in the LTs is assumed to have the same value for both frames,
    S and S'. This is the third [ and hidden ] postulate of special relativity. It is a postulate because it does not follow from any logical considerations. Think about it. Every variable in the LTs has a primmed and unprimed version, except v. There's
    an x and an x'. There's a t and a t'. There is a v, but there is no v'. c is a constant of course.

    Follow Sylvia's advice and assume that SR is true. Therefor the LTs are assumed true also. Then it necessarily follows that the coordinate velocity v' must be numerically equivalent to the proper relative velocity v. v = v'. Now construct v' by using
    the LTs: find the ratio of x' to t' which is v'. Now substitute v' back into the LTs where v occurs. The results make a laughingstock of SR. Reductio ad absurdum.

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  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Mon May 1 19:02:56 2023
    On Monday, May 1, 2023 at 6:02:03 PM UTC-7, gehan.am...@gmail.com wrote:
    The initial objection to the ballistic theory of light came from the results of
    the De Sitter experiment under Newtonian physics.

    Not at all. The initial objection to the ballistic theory was the interference effects of light, such as diffraction, which Newton humself acknowledged could not be readily explained in terms of a ballistic theory. This was shown conclusively in Young'
    s experiment around 1800, demonstrating that light exhibits wavelike interference. For the next hundred years, the wave conception of light was the most useful for making progress, accounting for all phenomena until things like black-body radiation and
    the photo-electric effect (which, when combined with special relativity, led to quantum electrodynamics).

    the velocity of emission of light is not constant relative to the source.

    No, in terms of the standard inertial coordinates in which any given object (including a source of light) is at rest, any pulse of light in vacuum propagates at the speed c. This applies whether the light was emitted by that object or not. Remember,
    velocities can't be specified "relative to objects", they can only be specified in terms of a given system of coordinates. In popular accounts some writers conflate an object with the standard inertial coordinates in which that object is at rest, and
    when they talk about velocities relative to that object they mean velocities in terms of that coordinate system. Most people are not too confused by this sloppy way of talking, but certain individuals are led astray by it, so it's important to be clear
    about it.

    the velocity of emission of light relative to the surface is different depending on the
    position of the Earth.

    No. Again, every pulse of light propagates in vacuum at the speed c in terms of any and every standard system of inertial coordinates, including the system in which the earth is at rest at any given time.

    Is this the meaning of independent of the 'motion of the source'?

    The meaning is that if one bulb is moving away from you and another is moving toward you, and at the moment when they pass each other they each emit a flash of light, the flashed reach you simultaneously. This is true even though one bulb was moving
    away and the other moving toward you. Again, light propagates in vacuum at the speed c in terms of any standard system of inertial coordinates. Note that you can't possibly understand this until you learn what a standard system of inertial coordinates
    is, which you will never learn, because you don't want to.

    I am simply asking what the rule for velocity of emission from
    the surface of a star is.

    Again, the velocity of a pulse of light in vacuum is c in terms of any standard system of inertial coordinates. This is telling you something about light, and something about standard systems of inertial coordinates. But it would help you immensely to
    forget about light and just consider two material particles A and B approaching you from the left and the right respectively at speed 0.75c in terms of the standard inertial coordinates in which you are at rest. The difference between their speeds in
    terms of those coordinates is 1.5c. However, in terms of the standard inertial coordinate system in which A is at rest, B is moving at speed (24/25)c. Do you understand this?

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  • From Tom Roberts@21:1/5 to gehan.am...@gmail.com on Mon May 1 22:36:18 2023
    On 5/1/23 1:10 AM, gehan.am...@gmail.com wrote:
    [the DeSitter double star experiment. everything in vacuum]
    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?

    Viewed from the reference frame of the earth (presumed to be inertial,
    to keep the context SR), one cannot observe its speed "relative to the
    surface of the star", because one can only observe relative to the
    reference frame one is using.

    One can CALCULATE its speed relative to the (locally) inertial frame in
    which the surface of the star is at rest. One must use the Lorentz
    composition of velocities, which of course obtains c.

    One can CALCULATE the closing speed of the light and star surface, using
    the reference frame of the earth. With the star moving with speed v
    relative to that frame, the closing speed is c-v when the star is
    approaching earth, and c+v when receding.

    Regardless of your desires, the closing speed between two objects
    measured in a third frame is not at all the same as the speed of one
    object relative to the other (rest frame). These are QUITE DIFFERENT
    concepts. (There is a mathematical quirk that when one uses Galilean
    relativity they have the same numerical value; this is only an
    approximation in the world we inhabit.)

    Tom Roberts

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  • From Maciej Wozniak@21:1/5 to Tom Roberts on Mon May 1 22:32:29 2023
    On Tuesday, 2 May 2023 at 05:36:31 UTC+2, Tom Roberts wrote:
    On 5/1/23 1:10 AM, gehan.am...@gmail.com wrote:
    [the DeSitter double star experiment. everything in vacuum]
    Question: If light travels from the star at velocity c relative to
    the Earth, at what relative velocity does it have relative to the
    surface of the star, when viewed from the reference frame in which
    the Earth?
    Viewed from the reference frame of the earth (presumed to be inertial,
    to keep the context SR), one cannot observe its speed "relative to the surface of the star", because one can only observe relative to the
    reference frame one is using.

    One can CALCULATE its speed relative to the (locally) inertial frame in
    which the surface of the star is at rest. One must use the Lorentz composition of velocities, which of course obtains c.

    One can CALCULATE the closing speed of the light and star surface, using
    the reference frame of the earth. With the star moving with speed v
    relative to that frame, the closing speed is c-v when the star is
    approaching earth, and c+v when receding.

    Regardless of your desires, the closing speed between two objects
    measured in a third frame is not at all the same as the speed of one
    object relative to the other (rest frame). These are QUITE DIFFERENT concepts. (There is a mathematical quirk that when one uses Galilean relativity they have the same numerical value; this is only an
    approximation in the world we inhabit.)

    In the world you inhabit, in the world of
    your insane delusions, where everyone is
    FORCED to obey your idiot guru and yourself.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Tue May 2 03:52:09 2023
    On Tuesday, May 2, 2023 at 7:02:58 AM UTC+5, Trevor Lange wrote:
    On Monday, May 1, 2023 at 6:02:03 PM UTC-7, gehan.am...@gmail.com wrote:
    The initial objection to the ballistic theory of light came from the results of
    the De Sitter experiment under Newtonian physics.
    ........
    the velocity of emission of light relative to the surface is different depending on the
    position of the Earth.
    No. Again, every pulse of light propagates in vacuum at the speed c in terms of any and every standard system of inertial coordinates, including the system in which the earth is at rest at any given time.
    Is this the meaning of independent of the 'motion of the source'?
    The meaning is that if one bulb is moving away from you and another is moving toward you, and at the moment when they pass each other they each emit a flash of light, the flashed reach you simultaneously. This is true even though one bulb was moving
    away and the other moving toward you. Again, light propagates in vacuum at the speed c in terms of any standard system of inertial coordinates. Note that you can't possibly understand this until you learn what a standard system of inertial coordinates is,
    which you will never learn, because you don't want to.

    This is an excellent example. In the above example, if the light bulbs are moving in an Aether stationary to me, that would make perfect sense.

    Let me try once again with a simple example. A child on a carousel is throwing a ball towards me when he is directly approaching me and when he is receding from me in the opposite direction, is throwing a ball to another person.

    It is indisputable in Newtonian physics that the child will have to use more force to throw the ball towards the person he is receding from, in order to make the velocity of the ball the same for each of the recipients.

    The receding star is throwing out light just as the approaching star is. Why is the light from the receding star thrown out faster relative to the surface of the star?

    Do you at least see the problem?

    I am simply asking what the rule for velocity of emission from
    the surface of a star is.
    Again, the velocity of a pulse of light in vacuum is c in terms of any standard system of inertial coordinates. This is telling you something about light, and something about standard systems of inertial coordinates. But it would help you immensely to
    forget about light and just consider two material particles A and B approaching you from the left and the right respectively at speed 0.75c in terms of the standard inertial coordinates in which you are at rest. The difference between their speeds in
    terms of those coordinates is 1.5c. However, in terms of the standard inertial coordinate system in which A is at rest, B is moving at speed (24/25)c. Do you understand this?

    No, this I do not understand. Without an absolute frame of reference, without an absolute rest frame, it is impossible to put limits on how fast objects can move relative to each other.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to patdolan on Tue May 2 03:44:58 2023
    On Tuesday, May 2, 2023 at 6:19:54 AM UTC+5, patdolan wrote:
    On Monday, May 1, 2023 at 6:02:03 PM UTC-7, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 6:06:43 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 10:05 pm, gehan.am...@gmail.com wrote:
    On Monday, May 1, 2023 at 2:36:38 PM UTC+5, Sylvia Else wrote:
    On 01-May-23 4:10 pm, gehan.am...@gmail.com wrote:
    You are all familiar with the DeSitter double star experiment.

    "In 1913, Willem de Sitter argued that if this was true, a star
    orbiting in a double-star system would usually, with regard to us, >>> alternate between moving towards us and away from us. Light emitted >>> from different parts of the orbital path would travel towards us at >>> different speeds. For a nearby star with a small orbital velocity (or
    whose orbital plane was almost perpendicular to our line of view) >>> this might merely make the star's orbit seem erratic, but for a
    sufficient combination of orbital speed and distance (and
    inclination), the "fast" light given off during approach would be >>> able to catch up with and even overtake "slow" light emitted earlier >>> during a recessional part of the star's orbit, and the star would >>> present an image that was scrambled and out of sequence. That is, >>> Kepler's laws of motion would apparently be violated for a distant >>> observer."

    Question: If light travels from the star at velocity c relative to >>> the Earth, at what relative velocity does it have relative to the >>> surface of the star, when viewed from the reference frame in which >>> the Earth?
    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star. >>
    This does not contradict the constancy of the speed of light, which >> relates to the speed as measured by an observer, not the speed of light
    relative to anything else.

    Of course, for an observer on the star, the light is observed to depart
    at speed c.

    Sylvia.

    If the star is moving towards the Earth at velocity v, then in the Earth
    frame the light is moving at velocity (c - v) relative to the star.

    If this is true, then have a look at this scenario.

    c

    X

    c

    In the Earth's frame of reference, light travels at c relative to the Earth. That means the relative velocity between the light and the surface of the star is c-v in the bottom case, where the star is approaching the Earth.

    When the same star is moving away from the Earth, we have the relative velocity between light or a particular photon or group of photons moving at c+v relative to the surface of the star.

    You can call this closing speed or relative speed.

    The fact is that the light is emitted at a different relative velocity relative to the surface of the star depending on the direction it is travelling - towards the Earth or away.
    If the observer on Earth seeks to calculate the speed that an observer on the star sees the light emitted, they must use the velocity composition formula. If the star is moving towards the Earth at velocity v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.

    That is, in the frame of a observer on the star, the light is emitted at velocity c.

    The same applies if the star is moving away from the Earth.

    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.

    Doesn't this violate the 'First Postulate'?
    Clearly, not.

    Sylvia.
    The initial objection to the ballistic theory of light came from the results of the De Sitter experiment under Newtonian physics.
    If the ballistic theory was correct, and this is under Newtonian Physics, then the results would have been different, as the story goes.

    According to the ballistic theory, the velocity of emission of light relative to the source is constant. Since this was proved to be wrong by the experiment, as it is said, then the velocity of emission of light is not constant relative to the source.
    More than that, the velocity of emission of light relative to the surface is different depending on the position of the Earth.

    To meet your objections:
    If the observer on Earth seeks to calculate the speed that an observer on the star sees the light emitted, they must use the velocity composition formula. If the star is moving towards the Earth at velocity v, then the result will be (v + c)/[1 + (vc/c^2)], which is just c.
    The same applies if the star is moving away from the Earth.
    Are you saying the same formula applies for when the star is moving away from the Earth?
    In that case v1 <> v2 so will we get the same result, or do we have to apply a formula with different signs depending
    on the direction the start is moving, to or away from the Earth?

    I thought the velocity of the source does not matter, v can be taken to be +1, -10000, 0r 0.
    Is this the meaning of independent of the 'motion of the source'?
    Attempts to determine the velocity of emission by simple addition or subtraction assume that special relativity is wrong, and any contradictions discovered thereby are in the assumptions made in the calculation, not in special relativity.
    I am not attempting to determine the velocity of emission. I am simply asking what the rule for velocity of emission from
    the surface of a star is.

    Your answer:
    gahan, may I offer some advice when arguing relativity. Let me give you two sure-fire, tried-and-true debating strategies to permanently silence the Sylvias and Paul B. Andersons of this forum.

    1) Subject SR to planetary motion. Planetary motion falsified SR almost immediately after it was propounded by Einstein. Einstein's response to this falsification was to jettison gravity as the reason for planetary motion and invent a new reason for
    planetary motion; namely, GR. But GR doesn't rescue SR from falsification. Please check out to the Eponymous Dilemma in this regard.

    2) Never argue the algebra of SR. It is consistent. But only as long as the relativists get to define the premises/terms used in the LTs. The premise/term you want to challenge is v. The v in the LTs is assumed to have the same value for both frames, S
    and S'. This is the third [ and hidden ] postulate of special relativity. It is a postulate because it does not follow from any logical considerations. Think about it. Every variable in the LTs has a primmed and unprimed version, except v. There's an x
    and an x'. There's a t and a t'. There is a v, but there is no v'. c is a constant of course.

    Follow Sylvia's advice and assume that SR is true. Therefor the LTs are assumed true also. Then it necessarily follows that the coordinate velocity v' must be numerically equivalent to the proper relative velocity v. v = v'. Now construct v' by using
    the LTs: find the ratio of x' to t' which is v'. Now substitute v' back into the LTs where v occurs. The results make a laughingstock of SR. Reductio ad absurdum.

    Thank you, will look at that. The premises the algebra is based on are the key, yes.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Tue May 2 22:18:41 2023
    On 02-May-23 8:52 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 7:02:58 AM UTC+5, Trevor Lange wrote:
    On Monday, May 1, 2023 at 6:02:03 PM UTC-7, gehan.am...@gmail.com wrote: >>> The initial objection to the ballistic theory of light came from the results of
    the De Sitter experiment under Newtonian physics.
    ........
    the velocity of emission of light relative to the surface is different depending on the
    position of the Earth.
    No. Again, every pulse of light propagates in vacuum at the speed c in terms of any and every standard system of inertial coordinates, including the system in which the earth is at rest at any given time.
    Is this the meaning of independent of the 'motion of the source'?
    The meaning is that if one bulb is moving away from you and another is moving toward you, and at the moment when they pass each other they each emit a flash of light, the flashed reach you simultaneously. This is true even though one bulb was moving
    away and the other moving toward you. Again, light propagates in vacuum at the speed c in terms of any standard system of inertial coordinates. Note that you can't possibly understand this until you learn what a standard system of inertial coordinates is,
    which you will never learn, because you don't want to.

    This is an excellent example. In the above example, if the light bulbs are moving in an Aether stationary to me, that would make perfect sense.

    Let me try once again with a simple example. A child on a carousel is throwing a ball towards me when he is directly approaching me and when he is receding from me in the opposite direction, is throwing a ball to another person.

    It is indisputable in Newtonian physics that the child will have to use more force to throw the ball towards the person he is receding from, in order to make the velocity of the ball the same for each of the recipients.

    The receding star is throwing out light just as the approaching star is. Why is the light from the receding star thrown out faster relative to the surface of the star?

    For an observer on the surface of the star, the light leaves in all
    cases at speed c.

    For observers moving relative to the star, subtracting the velocity of
    the star from the velocity of the light the star emits is physically meaningless. It gives you a quantity, but so does averaging the numbers
    in a phone book.


    Do you at least see the problem?

    There is no problem.

    I am simply asking what the rule for velocity of emission from
    the surface of a star is.
    Again, the velocity of a pulse of light in vacuum is c in terms of any standard system of inertial coordinates. This is telling you something about light, and something about standard systems of inertial coordinates. But it would help you immensely to
    forget about light and just consider two material particles A and B approaching you from the left and the right respectively at speed 0.75c in terms of the standard inertial coordinates in which you are at rest. The difference between their speeds in
    terms of those coordinates is 1.5c. However, in terms of the standard inertial coordinate system in which A is at rest, B is moving at speed (24/25)c. Do you understand this?

    No, this I do not understand. Without an absolute frame of reference, without an absolute rest frame, it is impossible to put limits on how fast objects can move relative to each other.

    Only if you're assuming that special relativity is wrong.

    If you apply relativity, there is no rule preventing a speed faster than
    light, it's just that you'll never obtain one.

    Sylvia.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Tue May 2 06:52:34 2023
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.

    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.

    It is indisputable in Newtonian physics that the child will have to use more force to throw the ball towards the person he is receding from, in order to make the velocity of the ball the same for each of the recipients.

    Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz invariant.

    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?

    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are,
    by definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.

    Do you at least see the problem?

    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.

    Without an absolute frame of reference, it is impossible to put limits on how
    fast objects can move relative to each other.

    Be careful... the limits are on the speed of any mass energy or information in terms of any standard system of inertial coordinates. The key physical fact you are missing (and Newton was missing) is that every quantity E of localized energy has inertia
    E/c^2. From this, all of special relativity follows.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Wed May 3 04:48:56 2023
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients.
    Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?

    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?

    Would the wave fronts from the moving stars form a sphere or an ellipse?

    https://study.com/learn/lesson/red-shift-theory-explanation.html

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Wed May 3 22:15:11 2023
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote: >>> In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to >>> make the velocity of the ball the same for each of the recipients.
    Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.

    Not on my reading.


    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?

    Yes.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?

    You realise that the labels are what would happen if emission theory
    were correct. Since it's not correct, the labels are wrong, and there is
    no asymmetry to explain.


    Would the wave fronts from the moving stars form a sphere or an ellipse?

    A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference.

    Sylvia.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Wed May 3 22:59:12 2023
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients.
    Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory
    were correct. Since it's not correct, the labels are wrong, and there is
    no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.

    The only asymmetry is in the incorrect emission model. So why concern
    yourself with it?


    Would the wave fronts from the moving stars form a sphere or an ellipse?
    A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference.

    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?

    They're formed from the same photons, but the relativity of simultaneity
    comes into play, so for example, where and when a photon forms part of
    the wavefront one second after the emission is frame dependent.

    Sylvia.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Wed May 3 05:28:37 2023
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients.
    Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory
    were correct. Since it's not correct, the labels are wrong, and there is
    no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example, for
    the approaching star. Either way, there is assymetry.

    Would the wave fronts from the moving stars form a sphere or an ellipse?
    A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference.

    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Wed May 3 06:46:50 2023
    On Wednesday, May 3, 2023 at 4:48:58 AM UTC-7, gehan.am...@gmail.com wrote: On Wednesday, May 3, 2023 at 5:28:39 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.

    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant.... which they are. Other phenomena are inconsistent with a stationary aether, but all the phenonena are consistent with local Lorentz invariance.

    It is indisputable in Newtonian physics that the child will have to use more force to throw the ball towards the person he is receding from, in order to make the velocity of the ball the same for each of the recipients.

    Right, and also in special relativity, although the precise difference in the required force is slightly different than in Newtonian physics, because Newton's laws aren't Lorentz invariant, whereas the actual laws of mechanics are Lorentz invariant.

    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?

    Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the light propagates at c. It is
    impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by definition, coordinates in
    terms of which the laws of physics take the same simple isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems related by Lorentz
    transformations.

    Do you at least see the problem?

    Well, of course I see "the problem", i.e., the fact that the phenomena are not consistent with Galilean invariance...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only
    way in which they can be reconciled, i.e., Lorentz invariance.

    In a double star system, does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?

    In terms of each of the different inertial coordinate systems in which each individual star, the center of mass of the stars, and the earth, are respectively at rest, the speed of light is c, and these coordinate systems are related by Lorentz
    transformations. Do you understand this?

    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the
    surface and c+v to the surface of the star?

    Your sentence doesn't parse in English, but note that the drawing is depicting a misunderstanding of the phenomena, i.e., it is illustrating a hypothesis that is shown to be false. The correct drawing of the situation, consistent with the actual
    phenomena, shows that the speed of light is c in terms of each of the inertial coordinate systems as described above. Do you understand this?

    Would the wave fronts from the moving stars form a sphere or an ellipse?

    Each pulse of light (emitted in all directions) emanates outward as an expanding spheres in terms of each of the standard inertial coordinate systems. Do you understand this?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Prokaryotic Capase Homolog@21:1/5 to gehan.am...@gmail.com on Wed May 3 07:25:39 2023
    On Wednesday, May 3, 2023 at 6:48:58 AM UTC-5, gehan.am...@gmail.com wrote:

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    The author of your linked image was Willem de Sitter.

    You had best reconsider your statement that the c-v and c+v
    labels are reversed.

    You are clearly misinterpreting the image

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Wed May 3 20:02:29 2023
    On Wednesday, May 3, 2023 at 6:00:19 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients. >>>> Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory
    were correct. Since it's not correct, the labels are wrong, and there is >> no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.
    The only asymmetry is in the incorrect emission model. So why concern yourself with it?

    Would the wave fronts from the moving stars form a sphere or an ellipse? >> A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference. >>
    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?
    They're formed from the same photons, but the relativity of simultaneity comes into play, so for example, where and when a photon forms part of
    the wavefront one second after the emission is frame dependent.

    Sylvia.

    That is a good explanation, though I cannot accept it. Part of my problem is that the concepts associated with SRT are not concisely stated, not correctly stated, for example 'moving clocks slow down' etc.

    So each observer is stuck in his own reality if he is moving with respect to another pbserver.

    Tell me, in a certain configuration of Relativistic time and space, could you die before you were born?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Prokaryotic Capase Homolog on Wed May 3 20:32:46 2023
    On Wednesday, May 3, 2023 at 7:25:42 PM UTC+5, Prokaryotic Capase Homolog wrote:
    On Wednesday, May 3, 2023 at 6:48:58 AM UTC-5, gehan.am...@gmail.com wrote:

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)
    The author of your linked image was Willem de Sitter.

    You had best reconsider your statement that the c-v and c+v
    labels are reversed.

    You are clearly misinterpreting the image

    The image simply depicts the ballistic theory of light, where the light is travelling at different velocities c-v and c+v at A and B.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Wed May 3 20:30:25 2023
    On Wednesday, May 3, 2023 at 6:46:51 PM UTC+5, Trevor Lange wrote:
    On Wednesday, May 3, 2023 at 4:48:58 AM UTC-7, gehan.am...@gmail.com wrote: On Wednesday, May 3, 2023 at 5:28:39 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant.... which they are. Other phenomena are inconsistent with a stationary aether, but all the phenonena are consistent with local Lorentz invariance.

    Agreed. Lorentz invariance was created for that.

    You are very patient, are you a Professor? Lucky students!
    Don't have to answer.

    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients.
    Right, and also in special relativity, although the precise difference in the required force is slightly different than in Newtonian physics, because Newton's laws aren't Lorentz invariant, whereas the actual laws of mechanics are Lorentz invariant.

    Agreed about Newton. Accepted about Lorentz, for the moment.

    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the light propagates at c. It is
    impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way.

    This way is known as a Lorentz transformation. Standard inertial coordinates are, by definition, coordinates in terms of which the laws >of physics take the same simple isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (
    check for yourself) >signifies that they take the same form in terms of coordinate systems related by Lorentz transformations.

    .. confirmed by experiments, but the existence of the theory did not automatically mean that it would be confirmed by experiments..

    Do you at least see the problem?
    Well, of course I see "the problem", i.e., the fact that the phenomena are not consistent with Galilean invariance...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and
    only way in which they can be reconciled, i.e., Lorentz invariance.

    OK


    In a double star system, does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    In terms of each of the different inertial coordinate systems in which each individual star, the center of mass of the stars, and the earth, are respectively at rest, the speed of light is c, and these coordinate systems are related by Lorentz
    transformations. Do you understand this?

    The systems are related by Loretnz transformations, yes.

    Is there a reason behind the asymmetry in the system clearly viewed in this
    image, where on one side of the orbit the star emits light at c-v relative to the
    surface and c+v to the surface of the star?

    Your sentence doesn't parse in English, but note that the drawing is depicting a misunderstanding of the phenomena, i.e., it is illustrating a hypothesis that is shown to be false. The correct drawing of the situation, consistent with the actual
    phenomena, shows that the speed of light is c in terms of each of the inertial coordinate systems as described above. Do you understand this?

    Haste makes waste. So here we go:

    In the diagram, when viewed from above, we see a system with two stars orbiting a common center of mass. Suppose we had a probe at rest in the Earths frame of reference with a camera pointing down on this system. The probe measures the tangential
    velocity of the surface of the star at each point in its orbit when the star is travelling directly toward Earth and away from the Earth. It measure this velocity to be v1 in the case where the surface of the star is moving towards the Earth and v2 at
    the point where the surface of the star is moving directly away.

    If we use the inertial coordinate system in which the Earth, the center of mass of the stars (assumed to be at rest), then we can see that the surface of the star (there are two, let's use one for the moment), is moving towards the Earth at different
    velocities, where v1 and v2.

    If we assume that the light from the star is moving at c in the inertial frame of reference that we chose, then we can see that if we subtract velocities, we have the relative speeds or closing speeds of the star surface and emitted light working out to
    be c-v and c+v.

    If I accept that this is all fine with Special Relativity, the question still arises as to why there are two different phenomena occurring here, where light is emitted at different velocities relative to the surface of the star at different points of
    the orbit.

    There is an asymmetry or I think you call it anisotropy.

    Would the wave fronts from the moving stars form a sphere or an ellipse?

    Each pulse of light (emitted in all directions) emanates outward as an expanding spheres in terms of each of the standard inertial coordinate systems. Do you understand this?

    To each his own.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dono.@21:1/5 to gehan.am...@gmail.com on Wed May 3 20:37:08 2023
    On Wednesday, May 3, 2023 at 8:02:31 PM UTC-7, gehan.am...@gmail.com wrote:

    That is a good explanation, though I cannot accept it.

    This is because you are mentally ill. Cannot be fixed.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Thu May 4 13:41:55 2023
    On 04-May-23 1:02 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 6:00:19 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients. >>>>>> Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest, the
    light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are, by
    definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture:

    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory
    were correct. Since it's not correct, the labels are wrong, and there is >>>> no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.
    The only asymmetry is in the incorrect emission model. So why concern
    yourself with it?

    Would the wave fronts from the moving stars form a sphere or an ellipse? >>>> A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference. >>>>
    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?
    They're formed from the same photons, but the relativity of simultaneity
    comes into play, so for example, where and when a photon forms part of
    the wavefront one second after the emission is frame dependent.

    Sylvia.

    That is a good explanation, though I cannot accept it. Part of my problem is that the concepts associated with SRT are not concisely stated, not correctly stated, for example 'moving clocks slow down' etc.

    "Moving clocks slow down, things contract" is popular science. The
    Lorentz transform is perfectly clear. Don't blame special relativity for misrepresentations made by people who do not understand it.

    So each observer is stuck in his own reality if he is moving with respect to another pbserver.

    Tell me, in a certain configuration of Relativistic time and space, could you die before you were born?

    No, those two events are necessarily time-like separated, and so have a well-defined order. Birth accordingly occurs before death in all frames.

    Sylvia.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Wed May 3 21:55:54 2023
    On Thursday, May 4, 2023 at 9:23:53 AM UTC+5, Trevor Lange wrote:
    On Wednesday, May 3, 2023 at 8:30:27 PM UTC-7, gehan.am...@gmail.com wrote:
    .. confirmed by experiments, but the existence of the theory did not automatically mean that it would be confirmed by experiments..
    Right, the local Lorentz invariance of all physical laws is not a tautology, it is an empirical fact, subject to empirical falsification on many fronts... which makes it all the more impressive that it has never been falsified (in contrast with the
    beliefs of its critics, which have all been abundantly falsified).

    Would action at a distance falsify Lorentz?

    If we assume that the light from the star is moving at c in the inertial frame
    of reference that we chose...

    Again, it isn't an assumption, and it isn't just c in terms of that single standard system of inertial coordinates, it is c in terms of every standard system of inertial coordinates, including the system in which each star is at rest at any given
    moment, and the system in which the center of mass is at rest, and so on.

    Velocity c in every standard system of inertial coordinates.

    if we subtract velocities, we have the relative speeds or closing speeds...

    Those are two different things, in normal terminology. In general, if two objects A and B have speeds vA and vB in terms of any given system S of coordinates, the closing speed between them is the difference vA - vB, whereas the term "relative speed"
    normally refers to the closing speed in terms of a standard system of inertial coordinates in which one of the objects is at rest (meaning that either vA or vB is zero). Thus every relative speed is a closing speed, but not every closing speed is a
    relative speed. So, let's correct your statement, since you are talking about closing speeds but not relative speeds (and let's dispense with "surface of" since on this scale we can treat it as a point source):

    Yes, point source.

    In any system of coordinates, where if two objects A and B have speeds vA and vB and vA and vB are not zero, then closing speed is vA-vB.

    Relative speed is, where in a system of coordinates S, then vA or vB is zero, relative speed is vA or vB as the case may be.
    Maybe clumsily stated, I understand it.

    So what makes the two situations different, is it that closing speed can be -2c to 2c and relative speed can only vary between c and -c?

    That is one heck of a stipulation.


    if we subtract velocities, we have the closing speeds of the star and emitted light working out to be c-v and c+v.

    Right, in terms of the standard inertial coordinates in which the CoM is at rest, the closing speed between the emitted pulses and the star moving toward the earth is c-v, and the closing speed between emitted pulses and the star moving away is c+v. (
    You shouldn't point to deSitter's drawing to illustrate this, because he was talking about something completely different.)

    The question still arises as to why there are two different phenomena occurring here, where light is emitted at different velocities relative to the surface of the star at different points of the orbit.

    You see, you smuggled in this puzzlement by semantically morphing from closing speed to relative speed. As explained above, those are two different things. The relative speed between the pulses and the respective stars is c in every case. The laws of
    physics governing the behavior of mechanics and electromagnetism, etc., take the same form in terms of every standard system of inertial coordinates. So this is all perfectly consistent. The closing speeds between entities are coordinate-dependent
    quantities (as is velocity itself!), so there is nothing paradoxical about the fact that closing speeds between intrinsically identical pairs of entities are different depending on how those pairs are moving relative to a certain system of coordinates.

    Let me re-qoute:

    "The closing speeds between entities are coordinate-dependent quantities (as is velocity itself!), so there is nothing paradoxical about the fact that closing speeds between intrinsically identical pairs of entities are different depending on how those
    pairs are moving relative to a certain system of coordinates."

    It may not be paradoxical but is there an assymetry?

    So if we define S as the frame in which the Earth, the centre of mass of the stars are at rest, we call the speed of the star towards the Earth as the relative speed?

    Then we have to call the third entity, the light itself and the point of emission marked as on the surface of the star as the closing speeds
    between the surface of the star and photons?

    This closing speed is different in each case but I still maintain that there is an asymmetry that has no physical cause.
    The difference is here that identical physical processes give different closing speeds depending on the direction of movement.

    If you can accept that as reality, then we are done.

    Would the wave fronts from the moving stars form a sphere or an ellipse?

    Each pulse of light (emitted in all directions) emanates outward as an expanding spheres in terms of each of the standard inertial coordinate systems. Do you understand this?

    To each his own.
    That isn't an answer, that's just running away. This isn't a matter of taste, like what's your favorite color, we're talking about objectively verifiable facts.

    I meant it as an answer: basically each person is their own wavefront bubble which is different from everyone elses.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Wed May 3 21:23:51 2023
    On Wednesday, May 3, 2023 at 8:30:27 PM UTC-7, gehan.am...@gmail.com wrote:
    .. confirmed by experiments, but the existence of the theory did not automatically mean that it would be confirmed by experiments..

    Right, the local Lorentz invariance of all physical laws is not a tautology, it is an empirical fact, subject to empirical falsification on many fronts... which makes it all the more impressive that it has never been falsified (in contrast with the
    beliefs of its critics, which have all been abundantly falsified).

    If we assume that the light from the star is moving at c in the inertial frame
    of reference that we chose...

    Again, it isn't an assumption, and it isn't just c in terms of that single standard system of inertial coordinates, it is c in terms of every standard system of inertial coordinates, including the system in which each star is at rest at any given moment,
    and the system in which the center of mass is at rest, and so on.

    if we subtract velocities, we have the relative speeds or closing speeds...

    Those are two different things, in normal terminology. In general, if two objects A and B have speeds vA and vB in terms of any given system S of coordinates, the closing speed between them is the difference vA - vB, whereas the term "relative speed"
    normally refers to the closing speed in terms of a standard system of inertial coordinates in which one of the objects is at rest (meaning that either vA or vB is zero). Thus every relative speed is a closing speed, but not every closing speed is a
    relative speed. So, let's correct your statement, since you are talking about closing speeds but not relative speeds (and let's dispense with "surface of" since on this scale we can treat it as a point source):

    if we subtract velocities, we have the closing speeds of the star and emitted light working out to be c-v and c+v.

    Right, in terms of the standard inertial coordinates in which the CoM is at rest, the closing speed between the emitted pulses and the star moving toward the earth is c-v, and the closing speed between emitted pulses and the star moving away is c+v. (
    You shouldn't point to deSitter's drawing to illustrate this, because he was talking about something completely different.)

    The question still arises as to why there are two different phenomena occurring here, where light is emitted at different velocities relative to the surface of the star at different points of the orbit.

    You see, you smuggled in this puzzlement by semantically morphing from closing speed to relative speed. As explained above, those are two different things. The relative speed between the pulses and the respective stars is c in every case. The laws of
    physics governing the behavior of mechanics and electromagnetism, etc., take the same form in terms of every standard system of inertial coordinates. So this is all perfectly consistent. The closing speeds between entities are coordinate-dependent
    quantities (as is velocity itself!), so there is nothing paradoxical about the fact that closing speeds between intrinsically identical pairs of entities are different depending on how those pairs are moving relative to a certain system of coordinates.

    Would the wave fronts from the moving stars form a sphere or an ellipse?

    Each pulse of light (emitted in all directions) emanates outward as an expanding spheres in terms of each of the standard inertial coordinate systems. Do you understand this?

    To each his own.

    That isn't an answer, that's just running away. This isn't a matter of taste, like what's your favorite color, we're talking about objectively verifiable facts.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Wed May 3 21:27:07 2023
    On Thursday, May 4, 2023 at 8:41:58 AM UTC+5, Sylvia Else wrote:
    On 04-May-23 1:02 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 6:00:19 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote: >>>>>> On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients. >>>>>> Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest,
    the light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are,
    by definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture: >>>>>
    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory >>>> were correct. Since it's not correct, the labels are wrong, and there is
    no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.
    The only asymmetry is in the incorrect emission model. So why concern
    yourself with it?

    Would the wave fronts from the moving stars form a sphere or an ellipse?
    A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres, >>>> but they are nevertheless spheres in the respective frames of reference.

    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?
    They're formed from the same photons, but the relativity of simultaneity >> comes into play, so for example, where and when a photon forms part of
    the wavefront one second after the emission is frame dependent.

    Sylvia.

    That is a good explanation, though I cannot accept it. Part of my problem is that the concepts associated with SRT are not concisely stated, not correctly stated, for example 'moving clocks slow down' etc.
    "Moving clocks slow down, things contract" is popular science. The
    Lorentz transform is perfectly clear. Don't blame special relativity for misrepresentations made by people who do not understand it.

    Ah yes, but I frequently thought that these people were on your side of the fence.

    Some textbooks are also ..um ... less than correct, as I understand. Not to mention professors, God forbid.


    So each observer is stuck in his own reality if he is moving with respect to another pbserver.

    Tell me, in a certain configuration of Relativistic time and space, could you die before you were born?
    No, those two events are necessarily time-like separated, and so have a well-defined order. Birth accordingly occurs before death in all frames.

    Sylvia.

    Nice to know. Life after death may be a timeless environment which will really wreak havoc with Relativity, should be fun.

    As a concept, God will have instant access to all information, meaning if that knowledge is real, Relativity is rendered obsolete.

    But I digress.

    My question has not been answered.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Dono. on Wed May 3 21:21:16 2023
    On Thursday, May 4, 2023 at 8:37:09 AM UTC+5, Dono. wrote:
    On Wednesday, May 3, 2023 at 8:02:31 PM UTC-7, gehan.am...@gmail.com wrote:

    That is a good explanation, though I cannot accept it.
    This is because you are mentally ill. Cannot be fixed.

    Your superior intellect cannot differentiate between low IQ and mental illness, none of which are mutually exclusive.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dono.@21:1/5 to gehan.am...@gmail.com on Wed May 3 22:20:55 2023
    On Wednesday, May 3, 2023 at 9:21:18 PM UTC-7, gehan.am...@gmail.com wrote:
    On Thursday, May 4, 2023 at 8:37:09 AM UTC+5, Dono. wrote:
    On Wednesday, May 3, 2023 at 8:02:31 PM UTC-7, gehan.am...@gmail.com wrote:

    That is a good explanation, though I cannot accept it.
    This is because you are mentally ill. Cannot be fixed.
    Your superior intellect cannot differentiate between low IQ and mental illness, none of which are mutually exclusive.
    You have both. Congratulations

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Wed May 3 23:30:10 2023
    On Wednesday, May 3, 2023 at 9:55:56 PM UTC-7, gehan.am...@gmail.com wrote:
    Would action at a distance falsify Lorentz?

    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)

    In any system of coordinates, where if two objects A and B have speeds vA and vB and vA and vB are not zero, then closing speed is vA-vB. Relative speed is, where in a system of coordinates S, then vA or vB is zero, relative speed is vA or vB as the
    case may be. So what makes the two situations different...?

    It isn't just two situations, it is infinitely many, due to the relationship between standard inertial coordinate systems (which is due to the inertia of energy). Consider two objects moving away from the origin of S in opposite directions on the x axis
    at velocities +u and -u, so their closing speed is u - (-u) = 2u. But their closing speed in terms of a system S' moving at speed v in terms of S is (u-v)/(1-uv) - (-u-v)/(1+uv) = 2u [(1-v^2)/(1-u^2v^2)]. This confirms that, in terms of S with v=0 we
    have closing speed 2u, but for any non-zero v we have a different closing speed, and for v=u (meaning the rightward object is at rest in terms of S') this yields the closing speed 2u/(1+u^2), which of course is the relative speed.

    So it isn't a binary thing with just two cases, there are infinitely many closing speeds for any pair of objects, depending on the coordinates, just as a single object has infinitely many speeds, depending on the coordinates. This is very elementary.
    Is there something about this that seems unclear to you?

    That is one heck of a stipulation.

    There is no stipulation here. These are objective facts.

    The closing speeds between entities are coordinate-dependent quantities (as is velocity itself!), so there is nothing paradoxical about the fact that closing speeds between intrinsically identical pairs of entities are different depending on how
    those pairs are moving relative to a certain system of coordinates.

    It may not be paradoxical but is there an assymetry?

    To the contrary, the relationship between relatively moving systems of standard inertial coordinates is perfectly symmetrical and reciprocal. Of course, in general the descriptions of phenomena may be more symmetrical in terms of one such system than in
    terms of another. For example, two identical stars revolving in orbit around each other have symmetrical motions in terms of the CoM coordinates, but in terms of other coordinates the descriptions of their motions are formally not symmetrical. Needless
    to say, this isn't changing the phenomena, it depends on the relationship between the phenomena and a coordinate system. This is extremely elementary reasoning, applicable to Newtonian physics as well as special relativity, so it is strange that you are
    puzzled by this.

    If we define S as the frame in which the Earth, the centre of mass of the stars are at
    rest, we call the speed of the star towards the Earth as the relative speed?

    That would be the relative speed of the star and the earth.

    Then we have to call the third entity, the light itself and the point of emission marked as on the surface of the star as the closing speeds between the surface of the star and photons?

    That sentence doesn't parse in English, and it is conceptually completely garbled. Perhaps you were struggling to ask something like : In terms of the standard inertial coordinates in which the earth is at rest, the light emitted from the approaching
    star has speed c and the approaching star has speed v, so is c-v the closing speed between the pulse of light and the star in terms of these coordinates? The answer of course is yes. And the speed of the pulse in terms of the standard inertial
    coordinates in which the star is at rest is c. We covered this already, remember?

    I still maintain that there is an asymmetry that has no physical cause.

    See above. Asymmetries between objects and coordinate systems are trivial, part of ordinary every-day kinematics that every human (and even most animals) easily grasp. You seem to be just pretending to be unable to grasp this. It has not some unique
    feature of special relativity. You have one speed in terms of one system of coordinates, and a different speed in terms of a different system of coordinates... are you seeking a physical cause of this asymmetry? You seem to be just constructing witless
    sophistries.

    The difference is here that identical physical processes give different closing speeds depending on the direction of movement. If you can accept that as reality, then we are done.

    Huh? You are profoundly confused. Again, objects have different speeds in terms of different coordinate systems, but they have invariant speed 0 in terms of their rest frame, and likewise pairs of objects have different closing speeds in terms of
    different coordinate systems, but they have an invariant relative speed, i.e., the closing speed in terms of the rest frame of one of the objects. This is simple grade school kinematics. And now... your cover your ears and make loud whooping sounds as
    you run away from the explanation.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Sylvia Else@21:1/5 to gehan.am...@gmail.com on Thu May 4 20:06:32 2023
    On 04-May-23 2:27 pm, gehan.am...@gmail.com wrote:
    On Thursday, May 4, 2023 at 8:41:58 AM UTC+5, Sylvia Else wrote:
    On 04-May-23 1:02 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 6:00:19 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote: >>>>>> On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote: >>>>>>>> On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients. >>>>>>>> Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian physics, because Newton's laws are not Lorentz invariant, whereas the actual laws of mechanics are Lorentz
    invariant.
    The receding star is throwing out light just as the approaching star is. Why is
    the light from the receding star thrown out faster relative to the surface of the star?
    You're not paying attention. Again, in terms of the standard inertial coordinates in which the star is at rest, the light (in vacuum) propagates at the speed c. Also, in terms of the standard inertial coordinates in which the earth is at rest,
    the light propagates at c. It is impossible for both of these things to be true... unless those two systems of coordinates are related to each other in a very specific way. This way is known as a Lorentz transformation. Standard inertial coordinates are,
    by definition, coordinates in terms of which the laws of physics take the same isotropic and homogeneous form, and the fact that the laws are Lorentz invariant (check for yourself) signifies that they take the same form in terms of coordinate systems
    related by Lorentz transformations.
    Do you at least see the problem?
    Well, of course I see "the problem"...everyone saw the problem... this is why Einstein said the two things are seemingly irreconcilable, and then he explained the one and only way in which they can be reconciled.


    Well at least you accept that there is a 'problem'.
    Not on my reading.

    When viewed from above the double star system looks this picture: >>>>>>>
    https://en.wikipedia.org/wiki/De_Sitter_double_star_experiment#/media/File:SitterKonstanz.png

    (In the diagram the c-v and c+v labels are reversed, since it illustrates the ballistic emission of light)

    Let me ask it this way: does the application of the Lorentz transformation in both cases give a constant velocity of light towards the Earth?
    Yes.

    OK so that is settled.


    Is there a reason behind the asymmetry in the system clearly viewed in this image, where on one side of the orbit the star emits light at c-v relative to the surface and c+v to the surface of the star?
    You realise that the labels are what would happen if emission theory >>>>>> were correct. Since it's not correct, the labels are wrong, and there is >>>>>> no asymmetry to explain.

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.
    The only asymmetry is in the incorrect emission model. So why concern
    yourself with it?

    Would the wave fronts from the moving stars form a sphere or an ellipse?
    A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres, >>>>>> but they are nevertheless spheres in the respective frames of reference. >>>>>>
    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?
    They're formed from the same photons, but the relativity of simultaneity >>>> comes into play, so for example, where and when a photon forms part of >>>> the wavefront one second after the emission is frame dependent.

    Sylvia.

    That is a good explanation, though I cannot accept it. Part of my problem is that the concepts associated with SRT are not concisely stated, not correctly stated, for example 'moving clocks slow down' etc.
    "Moving clocks slow down, things contract" is popular science. The
    Lorentz transform is perfectly clear. Don't blame special relativity for
    misrepresentations made by people who do not understand it.

    Ah yes, but I frequently thought that these people were on your side of the fence.

    Some textbooks are also ..um ... less than correct, as I understand. Not to mention professors, God forbid.


    So each observer is stuck in his own reality if he is moving with respect to another pbserver.

    Tell me, in a certain configuration of Relativistic time and space, could you die before you were born?
    No, those two events are necessarily time-like separated, and so have a
    well-defined order. Birth accordingly occurs before death in all frames.

    Sylvia.

    Nice to know. Life after death may be a timeless environment which will really wreak havoc with Relativity, should be fun.

    As a concept, God will have instant access to all information, meaning if that knowledge is real, Relativity is rendered obsolete.

    But I digress.

    My question has not been answered.


    I don't think all your questions ever will, because you seem determined
    to find some issue with special relativity.

    What motivates you here, I don't know, but I now doubt that it's a
    search for knowledge.

    I mentioned "concern troll" before.

    Sylvia.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Thu May 4 03:42:46 2023
    On Thursday, May 4, 2023 at 11:30:12 AM UTC+5, Trevor Lange wrote:
    On Wednesday, May 3, 2023 at 9:55:56 PM UTC-7, gehan.am...@gmail.com wrote:
    Would action at a distance falsify Lorentz?
    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)

    In any system of coordinates, where if two objects A and B have speeds vA and vB and vA and vB are not zero, then closing speed is vA-vB. Relative speed is, where in a system of coordinates S, then vA or vB is zero, relative speed is vA or vB as the
    case may be. So what makes the two situations different...?

    It isn't just two situations, it is infinitely many, due to the relationship between standard inertial coordinate systems (which is due to the inertia of energy). Consider two objects moving away from the origin of S in opposite directions on the x
    axis at velocities +u and -u, so their closing speed is u - (-u) = 2u. But their closing speed in terms of a system S' moving at speed v in terms of S is (u-v)/(1-uv) - (-u-v)/(1+uv) = 2u [(1-v^2)/(1-u^2v^2)]. This confirms that, in terms of S with v=0
    we have closing speed 2u, but for any non-zero v we have a different closing speed, and for v=u (meaning the rightward object is at rest in terms of S') this yields the closing speed 2u/(1+u^2), which of course is the relative speed.

    So it isn't a binary thing with just two cases, there are infinitely many closing speeds for any pair of objects, depending on the coordinates, just as a single object has infinitely many speeds, depending on the coordinates. This is very elementary.
    Is there something about this that seems unclear to you?
    That is one heck of a stipulation.
    There is no stipulation here. These are objective facts.
    The closing speeds between entities are coordinate-dependent quantities (as is velocity itself!), so there is nothing paradoxical about the fact that closing speeds between intrinsically identical pairs of entities are different depending on how
    those pairs are moving relative to a certain system of coordinates.

    It may not be paradoxical but is there an assymetry?
    To the contrary, the relationship between relatively moving systems of standard inertial coordinates is perfectly symmetrical and reciprocal. Of course, in general the descriptions of phenomena may be more symmetrical in terms of one such system than
    in terms of another. For example, two identical stars revolving in orbit around each other have symmetrical motions in terms of the CoM coordinates, but in terms of other coordinates the descriptions of their motions are formally not symmetrical.
    Needless to say, this isn't changing the phenomena, it depends on the relationship between the phenomena and a coordinate system. This is extremely elementary reasoning, applicable to Newtonian physics as well as special relativity, so it is strange that
    you are puzzled by this.

    If we define S as the frame in which the Earth, the centre of mass of the stars are at
    rest, we call the speed of the star towards the Earth as the relative speed?
    That would be the relative speed of the star and the earth.
    Then we have to call the third entity, the light itself and the point of emission marked as on the surface of the star as the closing speeds between the surface of the star and photons?
    That sentence doesn't parse in English, and it is conceptually completely garbled. Perhaps you were struggling to ask something like : In terms of the standard inertial coordinates in which the earth is at rest, the light emitted from the approaching
    star has speed c and the approaching star has speed v, so is c-v the closing speed between the pulse of light and the star in terms of these coordinates? The answer of course is yes. And the speed of the pulse in terms of the standard inertial
    coordinates in which the star is at rest is c. We covered this already, remember?
    I still maintain that there is an asymmetry that has no physical cause.
    See above. Asymmetries between objects and coordinate systems are trivial, part of ordinary every-day kinematics that every human (and even most animals) easily grasp. You seem to be just pretending to be unable to grasp this. It has not some unique
    feature of special relativity. You have one speed in terms of one system of coordinates, and a different speed in terms of a different system of coordinates... are you seeking a physical cause of this asymmetry? You seem to be just constructing witless
    sophistries.
    The difference is here that identical physical processes give different closing speeds depending on the direction of movement. If you can accept that as reality, then we are done.
    Huh? You are profoundly confused. Again, objects have different speeds in terms of different coordinate systems, but they have invariant speed 0 in terms of their rest frame, and likewise pairs of objects have different closing speeds in terms of
    different coordinate systems, but they have an invariant relative speed, i.e., the closing speed in terms of the rest frame of one of the objects. This is simple grade school kinematics. And now... your cover your ears and make loud whooping sounds as
    you run away from the explanation.

    If you have a frame of reference S, and you have two sources of light A and B moving along the X- axis in opposite directions, the closing speed between the light sources and the photons will be c-v and c+v. This is a consequence of the constancy of the
    speed of light, and is not unique to the binary star systems.

    One can call it asymmetry, but that is a necessary consequence.

    Thanks for explaining closing speeds and relative speeds.

    Would action at a distance falsify Lorentz?
    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)

    OK. So looks like I believe action at a distance is a real thing, hence the conflict.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Sylvia Else on Thu May 4 03:48:22 2023
    On Wednesday, May 3, 2023 at 6:00:19 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 10:28 pm, gehan.am...@gmail.com wrote:
    On Wednesday, May 3, 2023 at 5:15:56 PM UTC+5, Sylvia Else wrote:
    On 03-May-23 9:48 pm, gehan.am...@gmail.com wrote:
    On Tuesday, May 2, 2023 at 6:52:35 PM UTC+5, Trevor Lange wrote:
    On Tuesday, May 2, 2023 at 3:52:11 AM UTC-7, gehan.am...@gmail.com wrote:
    In the above example, if the light bulbs are moving in an Aether stationary to me,
    that would make perfect sense.
    Right, and it would also make perfect sense if all the laws of physics are (locally) Lorentz invariant... which they are.
    It is indisputable in Newtonian physics that the child will have to use more
    force to throw the ball towards the person he is receding from, in order to
    make the velocity of the ball the same for each of the recipients. >>>> Right, and also in special relativity, although the precise difference in the required force is very slightly different than in Newtonian ......

    As I mentioned, the labels are for emission theory. However, if we assume a constant velocity c towards the Earth, the labels are reversed, so one one side it would show a velocity between the surface of the star and the emitted light for example,
    for the approaching star. Either way, there is assymetry.
    The only asymmetry is in the incorrect emission model. So why concern yourself with it?

    Would the wave fronts from the moving stars form a sphere or an ellipse? >> A sphere - both in the frame of the star, and in the frame of an
    observer moving relative to the star. There are not the same spheres,
    but they are nevertheless spheres in the respective frames of reference. >>
    Sylvia.

    Wow. This is relativity then.

    A sphere in the frame of the star, yes.

    If the star is moving relative to the observer, or the observer is moving relative to the star, another sphere consisting of a different set of photons in each case?

    A spherical wavefront of photons a sphere created out of nothing, where is the energy for that?
    They're formed from the same photons, but the relativity of simultaneity comes into play, so for example, where and when a photon forms part of
    the wavefront one second after the emission is frame dependent.

    Sylvia.


    Something you said earlier, to clarify:

    Light Source S1 is moving along the x- axis. O1 is stationary. S1 gives off a flash of light while moving.



    Observer O1

    The observer at O1 will see a spherical wavefront emanating from S1?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Thu May 4 06:50:40 2023
    On Thursday, May 4, 2023 at 3:42:48 AM UTC-7, gehan.am...@gmail.com wrote:
    If you have a frame of reference S, and you have two sources of light A and B
    moving along the X- axis in opposite directions, the closing speed between the
    light sources and the photons will be c-v and c+v. This is a consequence of the
    constancy of the speed of light, and is not unique to the binary star systems.

    Right, it is a consequence of the fact that energy has inertia (just as matter does), and hence standard inertial coordinates (in terms of which the equations of physics take their simple homogeneous and isotropic form, i.e., maximally symmetrical) are
    related by Lorentz transformations. Needless to say, if those sources of light have the same intrinsic frequencies, the light will have different energies and frequencies and wavelengths due to the Doppler effect, such that the behavior is entirely
    consistent with the laws of physics, regardless of which system we use. Anything else would result in gross asymmetries in the form of the natural laws. Understood?

    Would action at a distance falsify Lorentz?

    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)

    Just to clarify, I presume you are referring to instanteous (superluminal) action at a distance.

    Looks like I believe action at a distance is a real thing, hence the conflict.

    Well, if you believe counter-factual things, then there will certainly be conflicts between your beliefs and the facts... by definition. Go ahead and state what phenomena you believe exhibits superluminal conveyance of mass, energy, action, or
    information, and I'll be happy to explain why it doesn't. Or just run away... up to you.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Thu May 4 08:41:50 2023
    On Thursday, May 4, 2023 at 6:50:41 PM UTC+5, Trevor Lange wrote:
    On Thursday, May 4, 2023 at 3:42:48 AM UTC-7, gehan.am...@gmail.com wrote:
    If you have a frame of reference S, and you have two sources of light A and B
    moving along the X- axis in opposite directions, the closing speed between the
    light sources and the photons will be c-v and c+v. This is a consequence of the
    constancy of the speed of light, and is not unique to the binary star systems.
    Right, it is a consequence of the fact that energy has inertia (just as matter does), and hence standard inertial coordinates (in terms of which the equations of physics take their simple homogeneous and isotropic form, i.e., maximally symmetrical) are
    related by Lorentz transformations. Needless to say, if those sources of light have the same intrinsic frequencies, the light will have different energies and frequencies and wavelengths due to the Doppler effect, such that the behavior is entirely
    consistent with the laws of physics, regardless of which system we use. Anything else would result in gross asymmetries in the form of the natural laws. Understood?

    No, I do not understand. I understand that there is a need to make the laws of physics work seamlessly across frames of reference using the simplest transformations, however since I consider absolute motion not impossible but simply indeterminate, I
    cannot form an opinion.

    In a geocentric universe the Earth was thought to be absolutely at rest, however even this was an unwarranted assumptions, since a geocentric universe did not necessarily mean a geostationary universe.

    Would action at a distance falsify Lorentz?

    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)
    Just to clarify, I presume you are referring to instanteous (superluminal) action at a distance.

    Yes the usual science fiction wormholes and warp drives and so on.

    Looks like I believe action at a distance is a real thing, hence the conflict.

    Well, if you believe counter-factual things, then there will certainly be conflicts between your beliefs and the facts... by definition. Go ahead and state what phenomena you believe exhibits superluminal conveyance of mass, energy, action, or
    information, and I'll be happy to explain why it doesn't. Or just run away... up to you.

    Not ready to run away yet.

    Let me see if I can explain this concept. Even if information cannot be transmitted faster than the speed of light, this does not mean that we can make calculations and statements about events if that is the right term, using the laws of physics, about
    things that have no chance of informing us through the transmission of information through light.

    For example we know that the Sun is 8 light minutes away, so we make the statement that the sun is emitting photons right now and it will take 8 minutes to reach us. That is a information by calculation or deduction and is equally valid. So we are
    indeed projecting an absolute lattice of clocks throughout the universe when we do this. If we see an exploded star, we say that that star did not exist for some period of time into the past, since it exploded.

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  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Thu May 4 08:47:02 2023
    On Thursday, May 4, 2023 at 6:50:41 PM UTC+5, Trevor Lange wrote:
    On Thursday, May 4, 2023 at 3:42:48 AM UTC-7, gehan.am...@gmail.com wrote:
    If you have a frame of reference S, and you have two sources of light A and B
    moving along the X- axis in opposite directions, the closing speed between the
    light sources and the photons will be c-v and c+v. This is a consequence of the
    constancy of the speed of light, and is not unique to the binary star systems.
    Right, it is a consequence of the fact that energy has inertia (just as matter does), and hence standard inertial coordinates (in terms of which the equations of physics take their simple homogeneous and isotropic form, i.e., maximally symmetrical) are
    related by Lorentz transformations. Needless to say, if those sources of light have the same intrinsic frequencies, the light will have different energies and frequencies and wavelengths due to the Doppler effect, such that the behavior is entirely
    consistent with the laws of physics, regardless of which system we use. Anything else would result in gross asymmetries in the form of the natural laws. Understood?
    Would action at a distance falsify Lorentz?

    Indeed it would, and none has ever been found. (No, quantum entanglement does not entail action at a distance.)
    Just to clarify, I presume you are referring to instanteous (superluminal) action at a distance.

    Looks like I believe action at a distance is a real thing, hence the conflict.

    Well, if you believe counter-factual things, then there will certainly be conflicts between your beliefs and the facts... by definition. Go ahead and state what phenomena you believe exhibits superluminal conveyance of mass, energy, action, or
    information, and I'll be happy to explain why it doesn't. Or just run away... up to you.

    Then there is this:

    #####
    2. The Problem

    The problem arises from the fact that process theism (as well as other forms of temporalistic theism) seems to presuppose a cosmic "now," while the special theory of relativity has seemed, at least to most interpreters who have discussed the issue, to
    entail that no such "now" exists.

    To begin with relativity physics: I will not repeat here the detailed explanations, which can be found in the articles by Wilcox, Ford, and Fitzgerald, as to why, according to special relativity theory, a cosmic "now" apparently does not exist. The main
    point is summarized nicely by Fitzgerald:

    according to relativity theory there is no such thing as absolute simultaneity for spatially separated events. Certain pairs of events A and B are such that whether A is to be regarded as occurring before B, simultaneously with B, or after B, depends on
    the coordinate-system with respect to which one judges. These event pairs, which Whitehead calls "contemporaries" of one another, are picked out by the fact that no light signal travelling even in vacuo from either could reach the other. This entails
    that what counts as "the past" or "the future" is also relative to coordinate-systems. (PS 2:251)

    https://www.religion-online.org/article/hartshorne-god-and-relativity-physics/

    #####

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  • From Jane@21:1/5 to gehan.am...@gmail.com on Fri May 5 00:00:48 2023
    On Thu, 04 May 2023 08:47:02 -0700, gehan.am...@gmail.com wrote:

    On Thursday, May 4, 2023 at 6:50:41 PM UTC+5, Trevor Lange wrote:
    On Thursday, May 4, 2023 at 3:42:48 AM UTC-7, gehan.am...@gmail.com

    Then there is this:

    #####
    2. The Problem

    The problem arises from the fact that process theism (as well as other
    forms of temporalistic theism) seems to presuppose a cosmic "now," while
    the special theory of relativity has seemed, at least to most
    interpreters who have discussed the issue, to entail that no such "now" exists.

    The real problem is that some people have built a whole religion on the
    basis that time and space are somehow related. By using the term 'cosmic
    time' you are subtly agreeing with that notion.
    Time has nothing whatsoever to do with space. It is universal and
    independent dimension that possibly has several subdimensions, just as
    space does. Now here is NOW everywhere even if there is no way to
    actually prove that.


    #####





    --
    -- lover of truth

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  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Thu May 4 16:55:24 2023
    On Thursday, May 4, 2023 at 8:41:52 AM UTC-7, gehan.am...@gmail.com wrote:
    Go ahead and state what phenomena you believe exhibits superluminal conveyance of mass, energy, action, or information, and I'll be happy to explain why it doesn't.

    Even if information cannot be transmitted faster than the speed of light...

    Well, that settles that. You claimed superluminal conveyance of energy or information, but when I ask you to give me an example, you immediately concede that your claim was false... or at least that you have no interest in defending it rationally.

    We know that the Sun is 8 light minutes away...

    In terms of the standard inertial coordinates in which the sun is at rest, yes. Of course, in terms of other standard inertial coordinate systems the spatial distance between sun and earth is different.

    so we make the statement that the sun is emitting photons right now...

    Well, the meaning of "right now" (simultaneity) is coordinate-dependent. It means "at the same value of the time coordinate". Because of the inertia of energy, relatively moving systems of standard ienrtial coordinates have skewed temporal foliations.

    and it will take 8 minutes to reach us.

    In terms of the standard inertial coordinates in which the sun is at rest.

    That is a information by calculation or deduction and is equally valid.

    Nothing you've said provide any support for your counterfactual claim of superluminal propagation of energy or information, nor for your denial of the abundantly demonstrated local Lorentz invariance of all physical laws. Agreed?

    Problem: I presuppose a cosmic "now," while the special theory of relativity entails that no such "now" exists.

    Those words don't describe a problem for special relativity, nor even a conflict with your vague pre-supposition. You are free to define "cosmic now" to mean whatever you like. For example, in cosmology we often refer to the isotropic global temporal
    foliation in terms of which the CMBR and the galaxies are (locally) maximally isotropic. This does not conflict with the facts related to local standard inertial coordinates, in terms of which the laws of physics take the same simple form, regardless of
    how the system is moving relative to the local CMBR isotropic frame. That's is the meaning of local Lorentz invariance.

    This entails that what counts as "the past" or "the future" is also relative to coordinate-systems.

    Well, that's just a misunderstanding. The causal future of an event is the future light cone, and the causal past is the past light cone. These are absolute. Talking about spacelike-separated events as being in each other's past or future for purposes
    of this kind of discussion is just wrong. People just like to smuggle in the colloquial meanings of those words and conflate them with the causal meanings, to construct witless sophistries. You should disregard any writings that contain
    misunderstandings like that.

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  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Thu May 4 20:26:18 2023
    On Friday, May 5, 2023 at 4:55:26 AM UTC+5, Trevor Lange wrote:
    On Thursday, May 4, 2023 at 8:41:52 AM UTC-7, gehan.am...@gmail.com wrote:
    Go ahead and state what phenomena you believe exhibits superluminal conveyance of mass, energy, action, or information, and I'll be happy to explain why it doesn't.

    Even if information cannot be transmitted faster than the speed of light...

    Well, that settles that. You claimed superluminal conveyance of energy or information, but when I ask you to give me an example, you immediately concede that your claim was false... or at least that you have no interest in defending it rationally.


    I have no way of proving that superluminal conveyance of information is possible. Or do I? That raises an interesting question, is it possible to come up with a logical disproof of the second postulate, that is, a set steps that will lead to a
    contradiction? One way or the other, the matter will be settled.

    We know that the Sun is 8 light minutes away...

    In terms of the standard inertial coordinates in which the sun is at rest, yes. Of course, in terms of other standard inertial coordinate systems the spatial distance between sun and earth is different.


    We choose to use the internal coordinate system in which the sun is at rest. Of course it would not take a genius to figure out that running after a moving train with a tape measure in hand will not give you an accurate length for the train. When we
    talk about distances yes that is what we mean.

    so we make the statement that the sun is emitting photons right now...

    Well, the meaning of "right now" (simultaneity) is coordinate-dependent. It means "at the same value of the time coordinate". Because of the inertia of energy, relatively moving systems of standard ienrtial coordinates have skewed temporal foliations.
    and it will take 8 minutes to reach us.
    In terms of the standard inertial coordinates in which the sun is at rest.

    Yes we agree, so I have been using and I am used to this coordinate system.

    That is a information by calculation or deduction and is equally valid.
    Nothing you've said provide any support for your counterfactual claim of superluminal propagation of energy or information, nor for your denial of the abundantly demonstrated local Lorentz invariance of all physical laws. Agreed?

    Agreed. Can a calculation be considered a superluminal transfer of information? It may seem like a silly question, but I really am not clear about the answer, because of the various statements out there.

    Problem: I presuppose a cosmic "now," while the special theory of relativity entails that no such "now" exists.

    Those words don't describe a problem for special relativity, nor even a conflict with your vague pre-supposition. You are free to define "cosmic now" to mean whatever you like. For example, in cosmology we often refer to the isotropic global temporal
    foliation in terms of which the CMBR and the galaxies are (locally) maximally isotropic.

    I am a big fan of the CMBR frame of refrence.

    This does not conflict with the facts related to local standard inertial coordinates, in terms of which the laws of physics take the same >simple form, regardless of how the system is moving relative to the local CMBR isotropic frame. That's is the
    meaning of local Lorentz >invariance.

    Assume the laws of physics are the same, when referred to the local system of coordinates in which the 'observer' is at rest. The problem is when I try to observe a moving object, create a frame of reference in which that object is at rest, now given
    the speed of light is the same in both frames, how on Earth do I translate the calculations and measurements of everything else into my frame in a way that preserves those laws? I am no really interested, because I do not believe the speed of light is
    any sort of a limit, however it remains to be seen if that is provable or not.

    This entails that what counts as "the past" or "the future" is also relative to coordinate-systems.
    Well, that's just a misunderstanding. The causal future of an event is the future light cone, and the causal past is the past light cone. >These are absolute. Talking about spacelike-separated events as being in each other's past or future for purposes
    of this kind of >discussion is just wrong. People just like to smuggle in the colloquial meanings of those words and conflate them with the causal >meanings, to construct witless sophistries.

    Causal light cone meaning no effects can travel faster than the speed of light?

    You should disregard any writings that contain misunderstandings like that.

    This is a huge problem for me. For example I can view fifteen different twin paradox explanations on YouTube including one that says that the other fourteen are wrong.

    It is difficult because I have to figure out the official explanation within Relativity for various situations, these are sometimes contradictory.

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  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Thu May 4 22:06:59 2023
    On Thursday, May 4, 2023 at 8:26:21 PM UTC-7, gehan.am...@gmail.com wrote:
    Is it possible to come up with a logical disproof of the second postulate?

    Obviously not. You now understand that, in fact, light propagates in vacuum at the speed c in terms of every standard system of inertial coordinates. Why would your brain even be thinking of disproving something that you now understand to be true?
    Habit?

    We choose to use the internal [sic] coordinate system in which the sun is at rest.

    Sometimes, although for many terrestrial purposes we use the standard inertial coordinates in which the center of the earth is at rest (ECI), or in which the barycenter of the solar system is at rest, and sometimes we use systems that aren't even
    standard inertial coordiate systems at all.

    When we talk about distances yes that is what we mean.

    No, that isn't what you mean - you don't really know what you mean, because you've never thought about it carefully. You don't even really know what a standard system of inertial coordinates is.

    Can a calculation be considered a superluminal transfer of information?

    No, obviously not.

    The problem is when I try to observe a moving object, create a frame of reference in which that object is at rest, now given the speed of light is the same in both frames, how on Earth do I translate the calculations and measurements of everything else into my frame in a way that preserves
    those laws?

    By the Lorentz transformation. We covered this before, remember?

    I am not really interested, because I do not believe...

    Right, you have no real interest in science, you just enjoy rehearsing the same old denialist slogans, over and over, year after year, for your entire life.

    The causal future of an event is the future light cone, and the causal past is
    the past light cone. These are absolute and invariant.

    Causal light cone meaning no effects can travel faster than the speed of light?

    Your brain mnalfunctioned... there was no mention of the phrase "causal light cone". Again, the causal future of an event is the future light cone, and the causal past is the past light cone. These are absolute and invariant. Thus your erroneous claim
    that causal past and future are coordinate dependent was based on misunderstanding. Of course, coordinate past and future is coordinate dependent... duh. Your befuddlement is due to conflating the two.

    You should disregard any writings that contain misunderstandings like that.

    This is a huge problem for me.

    That is true. One of the most consistent characteristics of people like you is an inability to distinguish sense from nonsense. It's like some people are color blind. You can't distinguish between the writings of a complete dolt and the writings of an
    intelligent and rational person. They all look the same to you. And since you don't have the intellect to understand things yourself, and must rely on authorities to tell you what to believe, this inability to distinguish between rationality and idiocy
    is particularly debilitating.

    It is difficult because I have to figure out the official explanation...

    That's the charactistic crackpot lament, i.e., they are seeking the "official" (LOL) explanation. But that's all behind you now, right? You now understand standard inertial coordinate systems are related by Lorentz transformations. All your questions
    have been clearly and succinctly answered. Right?

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  • From Mikko@21:1/5 to gehan.am...@gmail.com on Fri May 5 11:13:49 2023
    On 2023-05-04 15:47:02 +0000, gehan.am...@gmail.com said:

    The problem arises from the fact that process theism (as well as other
    forms of temporalistic theism) seems to presuppose a cosmic "now,"
    while the special theory of relativity has seemed, at least to most interpreters who have discussed the issue, to entail that no such "now" exists.

    What some heretic religion says does not affect what happens in the real
    world. The correct religious understanding of time (as described in "Confessions" by St. Augustine) is consistent with special relativity.

    Mikko

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  • From gehan.ameresekere@gmail.com@21:1/5 to Mikko on Fri May 5 04:10:23 2023
    On Friday, May 5, 2023 at 1:13:52 PM UTC+5, Mikko wrote:
    On 2023-05-04 15:47:02 +0000, gehan.am...@gmail.com said:

    The problem arises from the fact that process theism (as well as other forms of temporalistic theism) seems to presuppose a cosmic "now,"
    while the special theory of relativity has seemed, at least to most interpreters who have discussed the issue, to entail that no such "now" exists.
    What some heretic religion says does not affect what happens in the real world. The correct religious understanding of time (as described in "Confessions" by St. Augustine) is consistent with special relativity.

    Mikko

    Is this what you mean?

    "He compares the “drops of time” that he perceives in everyday life (the ‘drops’ in question refer to a water clock, steadily counting time) to God’s eternity, in which “nothing is transient, but the whole is present” (St Augustine, 2008).
    In eternity, there is no such thing as transition from past to present to future. Eternity is simply one whole present moment."

    https://www.thecollector.com/what-is-time-st-augustine/

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  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Fri May 5 04:07:15 2023
    On Friday, May 5, 2023 at 10:07:01 AM UTC+5, Trevor Lange wrote:
    On Thursday, May 4, 2023 at 8:26:21 PM UTC-7, gehan.am...@gmail.com wrote:
    Is it possible to come up with a logical disproof of the second postulate?

    Obviously not. You now understand that, in fact, light propagates in vacuum at the speed c in terms of every standard system of inertial coordinates. Why would your brain even be thinking of disproving something that you now understand to be true?
    Habit?


    I am free to think, still, and ask the question. Of course if it was possible someone in the past 100 years would have done it - or maybe shouted down as critics.

    We choose to use the internal [sic] coordinate system in which the sun is at rest.

    Sometimes, although for many terrestrial purposes we use the standard inertial coordinates in which the center of the earth is at rest (ECI), or in which the barycenter of the solar system is at rest, and sometimes we use systems that aren't even
    standard inertial coordiate systems at all.

    OK

    When we talk about distances yes that is what we mean.
    No, that isn't what you mean - you don't really know what you mean, because you've never thought about it carefully. You don't even really know what a standard system of inertial coordinates is.

    Searching it.

    Can a calculation be considered a superluminal transfer of information?
    No, obviously not.

    Good. We have agreement here. You realize that subsequently it is possible to come up with data that would have previously been impossible to obtain due to speed of light limitations? For example if an event happened before the other.

    The problem is when I try to observe a moving object, create a frame of reference in which that object is at rest, now given the speed of light is the same in both frames, how on Earth do I translate the calculations and measurements of everything else into my frame in a way that preserves those laws?
    By the Lorentz transformation. We covered this before, remember?

    OK


    I am not really interested, because I do not believe...

    Right, you have no real interest in science, you just enjoy rehearsing the same old denialist slogans, over and over, year after year, for your entire life.

    I have no interest in coming up with any sort of theory. I am interested in trying to sort out what I have read so far, concerning Special Relativity. There are some good books recommended, I will be going through those and making my own notes.

    The causal future of an event is the future light cone, and the causal past is
    the past light cone. These are absolute and invariant.

    Causal light cone meaning no effects can travel faster than the speed of light?
    Your brain mnalfunctioned... there was no mention of the phrase "causal light cone". Again, the causal future of an event is the future light cone, and the causal past is the past light cone. These are absolute and invariant. Thus your erroneous claim
    that causal past and future are coordinate dependent was based on misunderstanding. Of course, coordinate past and future is coordinate dependent... duh. Your befuddlement is due to conflating the two.

    "Because signals and other causal influences cannot travel faster than light (see special relativity), the light cone plays an essential role in defining the concept of causality: for a given event E, the set of events that lie on or inside the past
    light cone of E would also be the set of all events that could send a signal that would have time to reach E and influence it in some way" - Wikipedia

    You probably know the rest of the details about the light cone. Could a relationship between non causal events be established outside the light cone? This question may not make any sense. For example which event happened before the other?

    You should disregard any writings that contain misunderstandings like that.

    This is a huge problem for me.
    That is true. One of the most consistent characteristics of people like you is an inability to distinguish sense from nonsense. It's like some people are color blind. You can't distinguish between the writings of a complete dolt and the writings of an
    intelligent and rational person. They all look the same to you. And since you don't have the intellect to understand things yourself, and must rely on authorities to tell you what to believe, this inability to distinguish between rationality and idiocy
    is particularly debilitating.

    It is difficult because I have to figure out the official explanation...

    That's the charactistic crackpot lament, i.e., they are seeking the "official" (LOL) explanation. But that's all behind you now, right? You now understand standard inertial coordinate systems are related by Lorentz transformations. All your questions
    have been clearly and succinctly answered. Right?

    Some questions have been answered, yes.

    To be fair, there are many qualified and respected scientists with different conceptions of the universe. It would be difficult for most people to tell, as in real life, what is correct and what is not. Are there parallel universes for example, or is
    that a matter of opinion?

    What if some textbooks are incorrect? You are right though, once you understand a theory well enough you will be able to sort out the incorrect explanations. For example some theories of aerodynamic lift which are incorrect can be now easily seen to be
    incorrect.

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  • From whodat@21:1/5 to Mikko on Fri May 5 12:54:58 2023
    On 5/5/2023 3:13 AM, Mikko wrote:
    On 2023-05-04 15:47:02 +0000, gehan.am...@gmail.com said:

    The problem arises from the fact that process theism (as well as other
    forms of temporalistic theism) seems to presuppose a cosmic "now,"
    while the special theory of relativity has seemed, at least to most
    interpreters who have discussed the issue, to entail that no such
    "now" exists.

    What some heretic religion says does not affect what happens in the real world. The correct religious understanding of time (as described in "Confessions" by St. Augustine) is consistent with special relativity.

    You must mean Augustine's circular reasoning then.

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  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Fri May 5 16:53:56 2023
    On Friday, May 5, 2023 at 4:07:18 AM UTC-7, gehan.am...@gmail.com wrote:
    You now understand that light propagates in vacuum at the speed c in terms of every standard system of inertial coordinates. Why would you even be thinking of disproving something that you now understand to be true? Habit?

    I am free to think...

    Sure, but (again) why would you think about disproving something that you understand to be true?

    Subsequently it is possible to come up with data that would have previously been impossible to obtain due to speed of light limitations. For example if an event happened before the other.

    Those two sentences don't parse in English. Could you try again to express what you mean?

    I am interested in trying to sort out what I have read so far, concerning Special Relativity.

    But you already fully understand that standard inertial coordinate systems are related by Lorentz transformations, and you understand why this is true, and you understand all the consequences of it. So is your activity now simply to review books to see
    how well they describe all this?

    "Because signals and other causal influences..." Wikipedia

    Are you able to articulate what your intention was in posting those words?

    Could a relationship between non causal events be established outside the light cone?
    For example which event happened before the other?

    But we already covered this, remember?

    To be fair, there are many qualified and respected scientists with different conceptions of the universe. It would be difficult for most people to tell, as in real life, what is correct and what is not.

    But you already understand local Lorentz invariance, and how we know it is true, and why it is true, and what the consequences of it are. Right? It's like if you have understood a proof of Pythagoras' theorem in Euclidean plane geometry... you know it
    is true, and why it is true. If someone tells you it's true, you know he is right, and if someone tells you it isn't true, you know he is wrong. There's no need for you to be searching for an authority, you should use your own brain and your own
    understanding.

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  • From Tom Roberts@21:1/5 to Jane on Sat May 6 00:10:37 2023
    On 5/4/23 7:00 PM, Jane wrote:
    Now here is NOW everywhere even if there is no way to actually prove
    that.

    Once again you display your personal ignorance. That claim takes you out
    of the realm of science and into theology -- your wishes and dreams are
    no constraint on the world we inhabit, or on the theories we construct
    to describe that world. They do, however, seem to be a constraint on how
    you "think"....

    Tom Roberts

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  • From Tom Roberts@21:1/5 to gehan.am...@gmail.com on Sat May 6 00:12:43 2023
    On 5/4/23 10:26 PM, gehan.am...@gmail.com wrote:
    is it possible to come up with a logical disproof of the second
    postulate, that is, a set steps that will lead to a contradiction?

    That is impossible -- armchair fantasies and gedanken experiments have
    no ability to refute SR or GR -- that requires a real experiment, and to
    date that has not happened.

    Tom Roberts

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  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Fri May 5 22:09:34 2023
    On Saturday, May 6, 2023 at 4:53:58 AM UTC+5, Trevor Lange wrote:
    On Friday, May 5, 2023 at 4:07:18 AM UTC-7, gehan.am...@gmail.com wrote:
    You now understand that light propagates in vacuum at the speed c in terms of every standard system of inertial coordinates. Why would you even be thinking of disproving something that you now understand to be true? Habit?

    I am free to think...

    Sure, but (again) why would you think about disproving something that you understand to be true?

    "It is the mark of an educated mind to be able to entertain a thought without accepting it."

    Aristotle

    https://www.brainyquote.com/quotes/aristotle_100584

    Right now I am entertaining the thought not accepting it, as it is not required.

    Subsequently it is possible to come up with data that would have previously been impossible to obtain due to speed of light limitations. For example if an event happened before the other.

    Those two sentences don't parse in English. Could you try again to express what you mean?

    In the train and lightning strikes thought experiment, it is possible to say which lightning strike happened before the other in by
    conducting an investigation after the fact.

    I am interested in trying to sort out what I have read so far, concerning Special Relativity.
    But you already fully understand that standard inertial coordinate systems are related by Lorentz transformations, and you understand why this is true, and you understand all the consequences of it. So is your activity now simply to review books to see
    how well they describe all this?

    I do not need to assume anything is true, just that it works. I need to read more that is all.

    "Because signals and other causal influences..." Wikipedia

    Are you able to articulate what your intention was in posting those words?

    "Because signals and other causal influences cannot travel faster than light "

    Simply stating the assumption.

    Could a relationship between non causal events be established outside the light cone?
    For example which event happened before the other?
    But we already covered this, remember?

    OK

    To be fair, there are many qualified and respected scientists with different conceptions of the universe. It would be difficult for most people to tell, as in real life, what is correct and what is not.
    But you already understand local Lorentz invariance, and how we know it is true, and why it is true, and what the consequences of it are. Right? It's like if you have understood a proof of Pythagoras' theorem in Euclidean plane geometry... you know it
    is true, and why it is true. If someone tells you it's true, you know he is right, and if someone tells you it isn't true, you know he is wrong. There's no need for you to be searching for an authority, you should use your own brain and your own
    understanding.

    "you should use your own brain and your own understanding."

    As far as I know that is what I am doing. Pythogoras' theorem can be easily demonstrated to be true visually.
    With Special Relativity the background assumptions are not so easily discerned.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Fri May 5 22:50:04 2023
    On Friday, May 5, 2023 at 10:09:36 PM UTC-7, gehan.am...@gmail.com wrote:
    Why would you think about disproving something that you understand to be true?

    Right now I am entertaining the thought not accepting it

    That's dishonest, because you evaded facing the falsification of your beliefs by claiming that you understood the facts, but now you admit that you did not understand the facts, you were merely lying and evading. So if you have any intellectual
    integrity, you are now obligated to go back and honestly face the falsification of your beliefs. Understand?

    as it is not required.

    Again, you previously lied and said you understood why the inertia of energy requires local Lorentz invariance, but now you admit your lie, so you need to go back and honestly confront the falsification of your beliefs.

    In the train and lightning strikes thought experiment, it is possible to say which
    lightning strike happened before the other in by conducting an investigation after
    the fact.

    It is easy to determine all the objective facts involving the strike events A and B, such as the fact that tA < tB and t'A > t'B for relatively moving systems of standard inertial coordinates x,t and x',t'. Do you understand this? (Remember, I'm not
    asking if you entertain this, I'm asking if you understand this. Please answer honestly.)

    I do not need to assume anything is true, just that it works.

    There is no need to assume things (in the sense you mean), the objective facts are all easily ascertainable and understandable.

    I need to read more that is all.

    No, you need to *think* more, and be more honest. You are already in possession of all the information needed to understand special relativity. All you need to do is think rationally.

    "Because signals and other causal influences cannot travel faster than light "
    Simply stating the assumption.

    Again, velocities can only be defined in terms of coordinate systems, and it is not an assumption but an empirical fact that light propagates in vacuum at speed c in terms of every standard system of inertial coordinates. Do you understand this?

    "you should use your own brain and your own understanding."
    As far as I know that is what I am doing.

    No, that is not what you are doing. You are carefully and dishonestly evading all rational thought. Your pattern of textual misconstrual and passive-aggressive evasion has evidently been evolved and refined over a period of many years, so by now it is
    second nature to you, and you mistake it for thinking.

    Pythogoras' theorem can be easily demonstrated to be true visually.
    With Special Relativity the background assumptions are not so easily discerned.

    But it's been fully and clearly explained to you, and the clear demonstrations have been pointed out to you, and it isn't all that difficult (e.g., comparable to Euclidean geometry), you simply run away from all rational engagement.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From gehan.ameresekere@gmail.com@21:1/5 to Trevor Lange on Fri May 5 23:42:21 2023
    On Saturday, May 6, 2023 at 10:50:05 AM UTC+5, Trevor Lange wrote:
    On Friday, May 5, 2023 at 10:09:36 PM UTC-7, gehan.am...@gmail.com wrote:
    Why would you think about disproving something that you understand to be true?

    Right now I am entertaining the thought not accepting it
    That's dishonest, because you evaded facing the falsification of your beliefs by claiming that you understood the facts, but now you admit that you did not understand the facts, you were merely lying and evading. So if you have any intellectual
    integrity, you are now obligated to go back and honestly face the falsification of your beliefs. Understand?

    It is possible to understand a portrayal of reality without accepting it as fact. It happens all the time especially in religion.


    as it is not required.
    Again, you previously lied and said you understood why the inertia of energy requires local Lorentz invariance, but now you admit your lie, so you need to go back and honestly confront the falsification of your beliefs.

    I do understand the need for Lorentz invariance, not about inertial of energy.

    In the train and lightning strikes thought experiment, it is possible to say which
    lightning strike happened before the other in by conducting an investigation after
    the fact.
    It is easy to determine all the objective facts involving the strike events A and B, such as the fact that tA < tB and t'A > t'B for relatively moving systems of standard inertial coordinates x,t and x',t'. Do you understand this? (Remember, I'm not
    asking if you entertain this, I'm asking if you understand this. Please answer honestly.)

    No. I understand that any event can be translated into another coordinate system.

    I do not need to assume anything is true, just that it works.
    There is no need to assume things (in the sense you mean), the objective facts are all easily ascertainable and understandable.
    I need to read more that is all.
    No, you need to *think* more, and be more honest. You are already in possession of all the information needed to understand special relativity. All you need to do is think rationally.

    I am thinking rationally as far as I am aware and that is true.

    "Because signals and other causal influences cannot travel faster than light "
    Simply stating the assumption.
    Again, velocities can only be defined in terms of coordinate systems, and it is not an assumption but an empirical fact that light propagates in vacuum at speed c in terms of every standard system of inertial coordinates. Do you understand this?
    "you should use your own brain and your own understanding."
    As far as I know that is what I am doing.

    I do not accept that "that light propagates in vacuum at speed c in terms of every standard system of inertial coordinates. "
    I do not believe it, I do not think it is true.

    Now what?

    Being in error is not mutually exclusive from using ones own brain and own understanding. These may be flawed.
    Call it flawed then.

    No, that is not what you are doing. You are carefully and dishonestly evading all rational thought. Your pattern of textual misconstrual and passive-aggressive evasion has evidently been evolved and refined over a period of many years, so by now it is
    second nature to you, and you mistake it for thinking.
    Pythogoras' theorem can be easily demonstrated to be true visually.
    With Special Relativity the background assumptions are not so easily discerned.
    But it's been fully and clearly explained to you, and the clear demonstrations have been pointed out to you, and it isn't all that difficult (e.g., comparable to Euclidean geometry), you simply run away from all rational engagement.

    What I know to be rationality, or my practice of rationality does not allow me to accept that light is measured by all 'observers'as travelling at c.

    So that is a problem with my rationality, then I am irrational, but according to you, since I can be rational and accept by irrationality nor can I be irrational and accept that I am irrational. I can also be ignorant, just like Dr. Albert Einstein was
    unaware of the nature of things , so they say, before 1900.

    The De Sitter discussion can now be considered closed, I will retire to the books and pen and paper and the recommended books to look at this further. I expect to be back in a few weeks.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Trevor Lange@21:1/5 to gehan.am...@gmail.com on Sat May 6 11:57:11 2023
    On Friday, May 5, 2023 at 11:42:23 PM UTC-7, gehan.am...@gmail.com wrote:
    I do understand the need for Lorentz invariance, not about inertial of energy.

    That is a self-contradictory statement. The essence of Lorentz invariance is the inertia of energy. They are essentially the same thing.

    It is easy to determine all the objective facts involving the strike events A and B, such as the fact that tA < tB and t'A > t'B for relatively moving systems of standard inertial coordinates x,t and x',t'. Do you understand this?

    No. I understand that any event can be translated into another coordinate system.

    That sentence makes no sense... An event has specific coordinates in terms of some specific system of coordinates, and it has other coordinates in terms of some other system of coordinates. We can determine the latter from the former by means of the
    transformation between those systems... that's what a coordinate transformation means. Now do you understand?

    I need to read more that is all.

    No, you don't need to read more, you need to *think* more, and be more honest. You are already in possession of all the information needed to understand special relativity. All you need to do is think rationally.

    I am thinking rationally as far as I am aware and that is true.

    But that's the problem: Your brain is incapable of distinguishing between sense and nonsense, between rationality and irrationality. There may not be any solution to this. The only hope is that you aren't actually incapable, you are simply unwilling,
    because you value your cherished juvenile fantasies above rationality and intellectual integrity. In that case, you could conceivably reform your character, and then with your new-found intellectual integrity you could finally understand things. But if
    your brain is genuinely incapable of thinking rationally (as seems to be the case), there is little hope for you.

    I do not accept that that light propagates in vacuum at speed c in terms of every
    standard system of inertial coordinates.

    Right, but the point is that this fact has been carefully explained to you, and you have been unable to even attempt to find any flaw in the explanation, so your denialism is irrational and dishonest. Agreed?

    Pythogoras' theorem can be easily demonstrated to be true visually.
    With Special Relativity the background assumptions are not so easily discerned.

    They are qualitatively the very same kinds of assertions. In terms of x,y coordinates corresponding to an orthoginal grid of standard rulers, the measure s along the interval from the origin to the point at x,y satisfies s^2 = x^2 + y^2. Likewise, in
    terms of x,t coordinates corresponding to an orthoginal grid of standard rulers and clocks, the measure s along the interval from the origin to the event at x,t satisfies s^2 = x^2 - t^2. We can, with suitable instruments, confirm both of these
    propositions by direct measurements. So what exactly is the basis of your denialism?

    My practice of rationality does not allow me to accept that light is measured
    by all 'observers' as travelling at c.

    Well, that is a sloppy (at best) statement. Observers can measure things in terms of any system of measurement they find convenienet, and it is not true that the speed of light is c in terms of all of them. The correct statement is that the speed of
    light in vacuum is c in terms of every standard system of inertial coordinates, which is a very special class of coordinate systems, with a very particular meaning. The is a logical consequence of the Pythagorean theorem up above. Also, you somehow
    need to get your brain to stop thinking purely in terms of light. Local Lorentz invariance is not just limited to light, it applies to everything.

    The De Sitter discussion can now be considered closed...

    Well, it was closed a century ago, among rational adults. For you, however, it remains open until you can summon the intellectual integrity to set aside your cherished fantasies and start thinking rationally. Agreed?

    --- SoupGate-Win32 v1.05
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