• Re: Relativistic vs. Euclidean geometry

    From Tom Capizzi@21:1/5 to DRLunsford on Mon Nov 8 10:33:24 2021
    [Moderator's note: This post arrived with paragraph-long lines being
    broken, but not at spaces between words. That is a standard encoding
    for lines which are too long. However, it is much better for the
    volunteer moderators if you figure out how to send paragraphs which have
    a sensible line length (say at most 72 characters). Even if it looks
    like that to you on your screen, that is not necessarily what is sent.
    I have reformatted it, but please send short lines in the future. By
    far the majority of posts arrive in a more or less acceptable format.
    Also, please send only 7-bit ASCII characters; usenet is essentially
    medium, despite some extensions being supported in some cases. As a
    result, the Greek letters have been garbled and will probably appear
    incorrect to most. In such cases, (pseudo-)LaTeX code, e.g. \alpha, but
    also \sqrt etc. could be used, but obviously not if there are many such symbols. -P.H.]

    On Thursday, September 16, 2004 at 8:09:24 AM UTC-4, DRLunsford wrote:
    This occured to me at lunch, and is sort of fun...
    We know that the Lorentz transformation can be derived from a
    group-theoretic analysis of space and time, based on simple
    assumptions of isotropy, linearity etc. There exist both synthetic and analytic versions of this derivation that have been posted here. The
    end result is, there is a parameter with the dimensions of a velocity
    that is either finite, or infinite, that characterizes the geometry.
    Of course, it is C.
    One might ask, is Euclidean geometry so characterized? The answer is
    yes!
    Metric geometry sits inside projective geometry by positing a
    fundamental quadric. In relativity it is of course the light cone - in
    1+1 dimensions
    x^2 - (ct)^2 = 0
    which can be factored
    (x - ct)(x + ct) = 0
    so x/t = +-c - this shows how the fundamental quadric is related to
    the characteristic parameter.
    What about Euclidean plane geometry? The fundamental quadric is
    x^2 + y^2 = 0
    which seems like an empty statement, but makes sense in the context of projective geometry as the "circular points at infinity". We can now
    factor this as
    (x - iy)(x + iy) = 0
    The characteristic parameter of Euclidean geometry is the imaginary
    unit! So "i" plays the role of the "speed of imaginary light" in
    Euclidean geometry :)
    This has a beautiful interpretation. Intuitively, one knows that, on
    the Euclidean plane, one can imagine a thing called "infinity" which
    can never be got closer to, from which all regular points are
    "infinitely" distant. No matter how far you go, you're always
    "infinitely" far away from "infinity". This is the *exactly analogous*
    result to the impossibility of attaining the speed C in relativity.
    This may be the most basic way complex numbers enter into physics.
    -drl

    This information needs to be combined with eigenvector decomposition based
    on the Lorentz matrix. In the first place, calling it the Lorentz matrix makers it appear to be a physics thing. Wrong. It was a simple, hyperbolic rotation long, long before Lorentz's name was attached to it.

    "> We know that the Lorentz transformation can be derived from a
    group-theoretic analysis of space and time, based on simple
    assumptions of isotropy, linearity etc."

    Nothing more sophisticated than Euclidean geometry is needed. Indeed,
    the hyperbolic geometry that underpins relativity was first used by the map-maker, Mercator, centuries before it was claimed by physics.
    Centuries before group math and relativity.

    The details of hyperbolic trigonometry were published in the mid-1700's.
    The "Lorentz" Transformation is nothing more than a restatement of the hyperbolic identities for the cosh and sinh of the sum of two hyperbolic angles. Given a hyperbolic angle, w, that is the sum of two independent variables, A and B, those identities are cosh(w) = cos(A+B) = cosh(A)cosh(B)+sinh(A)sinh(B), and sinh(w) =
    sinh(A)cosh(B)+cosh(A)sinh(B). A point, (x,y), on a unit hyperbola with horizontal symmetry satisfies the equation x²-y² = 1. The coordinates
    of this point are equal to (cosh(A),sin(A)). Since the addition of
    hyperbolic angles is commutative and linear, it doesn't matter which of
    the two angles refers to the initial state. The final state is just the
    sum of an initial state and an increment. There is a simple proof, using geometric algebra, that the sum of hyperbolic rotation angles is linear.
    So, we can state that the point (cosh(w),sinh(w)) = (cosh(B+A),
    sinh(B+A)). Using the above identities, cosh(B+A)= cosh(B)cosh(A)+sinh(B)sinh(A) sinh(B+A) = sinh(B)cosh(A)+cosh(B)sinh(A)
    The astute observer will notice that this is nothing more than an
    expansion of the linear algebra equation: â_cosh(w)â_ â_cosh(B) sinh(B)â_â_cosh(A)â_ â_ sinh(w)â_=â_sinh(B) cosh(B)â_â_ sinh(A)â_ In
    Greek symbols and more specific coordinates: â_ct'â_ â_ γ
    -βγâ_â_ctâ_ â_ r' â_=â_-βγ γâ_â_ r â_ Using the same identities,
    we can derive the hyperbolic identity of the tanh of the sum of two
    hyperbolic angles: v3 = c tanh(w) = c tanh(A+B) = c(sinh(A)cosh(B)+cosh(A)sinh(B))/(cosh(A)cosh(B)+sinh(A)sinh(B)) = c(sinh(A)/cosh(A)+sinh(B)/cosh(B))/(1+sinh(A)/cosh(A)*sinh(B)/cosh(B)) = c(tanh(A)+tanh(B))/(1+tanh(A)*tanh(B)) In its more familiar form, v1 = c tanh(A) and v2 = c tanh(B): (v1+v2)/(1+v1/c*v2/c), the velocity addition
    "rule" of special relativity. It's just a hyperbolic identity. Physics
    did not invent it, even if they take credit for it.

    "> Metric geometry sits inside projective geometry by positing a
    fundamental quadric. In relativity it is of course the light cone - in
    1+1 dimensions
    x^2 - (ct)^2 = 0
    which can be factored
    (x - ct)(x + ct) = 0"

    Minkowski's initial foray into relativity identified time as an
    imaginary component, so that the quadric becomes x^2 + (ict)^2 = x^2 -
    (ct)^2 = 0. This equation generates the rectangular hyperbola. In
    general, x^2 - (ct)^2 = ±s^2, where the choice of sign depends on an
    arbitrary convention. The two values, s and w, are coordinates in a
    Cartesian grid. They represent hyperbolic coordinates in which they are invariant in the absence of external forces. A shift of either
    coordinate has no effect on the other coordinate, a standard property of orthogonal coordinates. Since w can represent arbitrary combinations of rotation angles, it is convenient to divide it into 2 components, one
    being its initial value, w0, at some arbitrary time, t=0, and the other,
    its value at some future time, w1. Then w = w1-w0. It makes no
    difference if it is a reference to one frame which changes its
    hyperbolic angle, or a given frame that is observed by a non co-moving
    frame.

    Since we choose non-hyperbolic geometry, these coordinates must be
    transformed into our native coordinates to make sense to us. We have
    already observed that ct = s cosh(w) and r = s sinh(w). From these
    coordinates, we can restore the hyperbolic coordinates by using the
    inverse transform. s^2 = (ct)^2-r^2, and tanh(w) = r/ct. So, in
    Minkowski spacetime, the invariant is a coordinate transform to
    hyperbolic coordinates. Note that the hyperbolic rotation angle is the
    same for both frames. But is Minkowski's the only possible frame? No.

    Minkowski is referred to as pseudo-Euclidean. Considering that Einstein
    did not have the crutch of Minkowski trigonmetry when he first
    published, it is worth investigating the Euclidean version. As similar
    as it is to Minkowski, it is more productive to consider the Euclidean eigenvector decomposition. A limited version of this can be found in
    Hermann Bondi's k-calculus. The k in k-calculus, Bondi's "fundamental
    ratio", stands for an eigenvalue of the Lorentz matrix, from which he
    derives all the features of relativity. One of the tools that he uses
    in his derivation is measurements by radar. This is another intrinsic
    feature of eigenvector decomposition, because "> so x/t = +-c". These
    are the eigenvectors of the Lorentz matrix, the worldlines of photons.
    Bondi does not mention eigenvectors or eigenvalues, and misses some of
    the bigger picture. The Euclidean nature of this approach allows us to
    use conventional definition of the dot and cross-product, neither of
    which applies in Minkowski trigonometry. In terms of an arbitrary
    direction in space, r, for the frame velocity, the eigenvectors are ct=r
    and ct=-r. (Note: I use the constant c to accommodate arbitrary units
    for c. Because c in natural units may have a magnitude of 1, but it
    still has units. Dropping the c because it is unit in magnitude also
    drops the units. To maintain agreement of units on both sides of the
    equation, some conversion factor, like c, is still needed to make the
    units agree.) Coordinates on these two axes are (ct+r) and (ct-r). Their Euclidean cross-product has magnitude (ct+r)(ct-r) = c²t²-r² = s²,
    the Einstein Interval. But this is the exact same s that is the
    invariant hyperbolic magnitude. And if s^2 is invariant wrt hyperbolic rotation, then I propose that the factored version does not belong to Minkowski, It is Euclidean. And the Euclidean quadric, (ct)²+(ir)²
    does not apply to real trigonometry, but Minkowski trig, (ct)^2-r^2. It
    is, after all, pseudo-Euclidean.

    Minkowski reformulated his trigonometry so that none of the coordinates
    were imaginary, but the metric remained the same as in the earlier
    version. The transform used to generate Minkowski's light-cone axes is
    the same one that generates the real eigenvectors of the Lorentz matrix.
    Some contend that this disqualifies its use, because in Minkowski trig,
    the word real means Minkowski-real, which the rest of us would
    understand to be imaginary. And in Minkowski-speak, the dot product of
    an eigenvector with itself is 0. Since orthogonal means Minkowski
    orthogonal, the two light-cone "eigenvectors" (which are not real) are
    actually parallel, and their product is 0. And since they are Minkowski parallel, their cross-product does not exist. But the symmetry transform applies to a wide range of physical processes and attributes. Physics
    does not own it, nor do they get to decide where and when it can be
    used.

    The transform is almost auto-inverse, except for a scale factor. In the
    for m that I have applied it, it is a combination of 3 simple
    transforms. It is a scaling, a rotation and a mirror reflection.
    Although it is a rotation, it is not a unit rotation matrix. More
    important, its determinant is not positive. So, aside from the scaling,
    it can never be a Lorentz Transform of any given frame. In this
    application, the form was chosen so that the Euclidean/Minkowski
    horizontal hyperbola maps to the diagonal eigenvector hyperbola with the
    same invariant. But, geometrically, the invariant of the horizontal
    hyperbola is a vector, the semi-major axis of the hyperbola, while the invariant of the diagonal hyperbola is an invariant area. This can be
    seen in the coordinates of the vertex. For the horizontal unit
    hyperbola, the vertex is (1,0), and the invariant is the magnitude of
    this vector. For the diagonal hyperbola, the vertex is (1,1), for an
    area of the cross-product of 1. This is where the scale factor comes
    from. The magnitude of the semi-major axis to the vertex is â¨2, but in
    this isomorphism, length is irrelevant. Although the shape of what
    appears to be a bivector changes with hyperbolic rotation angle, its
    area remains invariant, being the result of a squeeze mapping of
    determinant, 1.

    Euclidean eigenvectors of the Lorentz matrix are truly real, as are the eigenvalues. Since real multiplication and real addition are both closed operations, their is no real linear transform that will result in a
    vector that is not in the same plane as its components. Minkowski "eigenvectors" are not real, as they require 3 dimensions to embed the light-cone hyperplane. As most critics make the assumption that if you
    are writing about special relativity, you must be using Minkowski trig,
    their irrelevant objections can simply be dismissed. We are talking
    about Euclidean geometry, like Einstein had to when he first published.
    And this is where it gets sticky for Einstein.

    He postulated that the speed of light is invariant to the relative
    velocity of either its source or the observer. He also asserted that the properties of time dilation and length contraction are physical. In
    terms of Euclidean geometry, these assertions are self-contradictory. In
    his books, he always uses two frames, one a reference frame and the
    other non co-moving. The essence of relativity is that it doesn't matter
    which of the two frames is considered stationary. His description of
    relativity only works for these two observers, because relative velocity
    is just 1 equation in 2 variables. Even for 2 observers, there is the
    infamous Twin Paradox. Based on only relative velocity, both observers
    can legitimately claim that the other one is dilated or contracted.
    While both observers can't actually be correct, one of them is correct,
    but perhaps unable to confirm it.

    If we introduce more observers at different relative velocities, we have
    a problem. Assuming we start with two observers, then one of them is
    correct. We can't be sure which one it is. But if we compare both of
    them to any of the additional observers, the one thing we can be sure
    of, is that none of the extra observers can be correct. According to relativity, one of any pair of differently moving observers is correct.
    Even if the original two observers can't agree about who is moving, they
    can both agree on the magnitudes of the dilation and the contraction.
    This applies to any pair formed from one of the first two and any of the additional observers. But they will agree on measurements that are not
    the same as the first pair. In an objective reality, this is a
    contradiction. Rather than discard a theory based on a contradiction,
    the mainstream physicists of the time discarded the objective reality.
    By giving each frame its own subjective reality, they erased the
    contradiction. It allows them to make fatuous statements like there is
    no reason to expect any two observers to agree on any measurement. Great science, isn't it?

    Since it is frequently useful to examine a problem from a different
    frame of reference, we shall look from the eigenvector frame. If we
    apply the symmetry transform to the reference frame, there is no
    relative velocity. Coordinates in this frame are determined by Bondi's
    radar technique, an integral feature of real eigenvectors. That means
    location in this plane is determined by two coordinates, both of which
    are invariant wrt relative velocity of any kind. In this trigonometry,
    the relative velocity is actually a third orthogonal coordinate. The
    entire plane of the first two coordinates is translated completely
    intact by the third coordinate. The interval between any two points on
    this plane is thus unaffected by relative velocity. Physical objects do
    not change size or shape due to relative velocity. This confirms that Einstein's theory is self-contradictory in Euclidean geometry. More
    important, it demonstrates that the measurement process itself is
    defective.

    In its attempt to legitimize the profession from the quacks of alchemy
    and metaphysics, the scientific method placed a premium on the repeated measurements of the same property. Agreement between multiple
    measurements allowed a consensus reality to be crafted. The simple truth
    is that this paradigm only applies to Newtonian physics. In plain
    language, this is WYSIWYG. But just like Newtonian physics breaks down
    at relativistic velocities, so does the standard of measurement. The self-contradictory assertions of time dilation and length contraction
    are mere artifacts of a false measurement. Euclidean geometry has
    another standard for comparing the magnitude of an unknown with the
    magnitude of a reference unit. It is the dot product. This does not
    apply to Minkowski geometry, where the dot product of eigenvector units
    with themselves is 0, and the cross-product of two different
    eigenvectors is not defined, because the eigenvectors are parallel.

    While the dot product is clearly defined for Euclidean geometry (and
    extended into inner and outer products), it can be expressed simply as
    the product of the magnitudes of the two factors with the cosine of the
    angle between them. For Newtonian physics, this reduces to the product
    of the unknown magnitude with the magnitude of the reference unit, 1,
    and the cosine of 0, also 1. In other words, WYSIWYG. For relativistic physics, this is not valid, because the angle between to moving frames
    is no longer 0. While it could be anything, experimental evidence
    confirms that the phase angle between two inertial frames that have been synchronized is not 0, despite the fact that all the axes (observable,
    that is) are parallel. It is defined by relative velocity as v/c =
    sin(phase).

    And this brings us to the core of special relativity. The phase angle
    defined this way is the gudermannian of the rapidity, the hyperbolic
    rotation angle. While it was studied extensively in the 18th century,
    its first application was much older. It is the basis of the brilliant achievement of the map-maker, Mercator. In hindsight, we can understand
    where the transform applies. Mercator, perhaps protecting his
    proprietary algorithm for map-making, did not reveal his secret. If we
    call the longitude angle Ï, and the latitude angle Ï, then the
    map-making rule is dÏ/dÏ = γ, the Lorentz factor, defined centuries
    before his birth. Ï is defined geometrically as the gudermannian of Ï.
    We can't see it or measure it, because it is the angle between
    dimensions of spacetime that are outside of the box that 4D spacetime
    traps us in. As with much of physics, they appropriated it, as the
    parametric angle used to manipulate velocity as a convenience.

    The Lorentz factor was originally an empirically determined fudge factor
    that made the predictions of Newton's law agree with experimental
    evidence. Now, they claim that it was Newton's "Law" that was wrong, and
    that the relativistic momentum is just what a moving object is supposed
    to have. What a surprise. Newton's Law is short by exactly the same
    factor as time dilation and length contraction, both shown to be
    illusions. And by giving such a circular definition, there is no need
    for the other relativistic canard, relativistic mass. But if we multiply relativistic momentum by the same projection cosine as we used for time
    and distance, we find the result to be measurable Newtonian momentum.
    The dot product triumphs again.

    So far, I haven't found any situation in which Euclidean geometry cannot
    be used. As an isomorphism of Minkowski, it does not require that the
    same operations get the same result. So, the Minkowski dot product
    yields the same results as the Euclidean cross-product, another variant
    of multiplication. In Euclidean geometry, the dot and cross-products
    form an orthogonal basis, so pseudo-Euclidean Minkowski trig rotates the
    basis 90 degrees and gets the same result. I think it is long past time
    that we critically re-evaluate the core premises of special relativity. Especially the artificial restriction to 4 real dimensions. I know that
    this describes Euclidean geometry, but eigenvector geometry is different
    from Euclidean in some important ways. In the same way that Minkowski
    could reformulate his geometry with 4 real coordinates while retaining
    the pseudo-Euclidean metric, I have found that there is an isomorphism
    between ordered sets of n-tuples of real numbers and hypercomplex
    numbers. The simplest is (a,b) â_ a+bi. This mapping extends at least to bioctonions, which are ordered pairs of biquaternions, and are
    equivalent to biquaternions of complex scalars instead of real scalars.
    The bleatings of the relativity cult that no theory has been confirmed
    more than relativity are totally irrelevant. Even Einstein agreed, "No
    amount of experimentation can ever prove me right; a single experiment
    can prove me wrong." How about a single gedanken experiment?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)