But ever since NASA’s Voyager flybys in 1979 and the flagship
1995-2003 Galileo mission to Jupiter, scientists have assembled an increasingly convincing body of evidence that beneath Europa's frozen
surface lies a massive saltwater ocean containing 2-3 times the water
in all the oceans on Earth.
Scientists suspect that Europa’s sea, which lies about 60 mi. beneath
the surface, remains liquid due to the heat of tidal flexing as
Jupiter’s gravity stretches and squeezes the moon. Europa, with a
diameter of about 1,900 mi.—slightly smaller than Earth’s Moon—circles Jupiter every 3.5 days. Like Earth’s Moon, Europa is tidally locked, resulting in one hemisphere always facing Jupiter. Tidal forces on
Europa are about 1,000 times stronger than the Moon’s effect on Earth.
Europa’s surface is young—just 40-90 million years old— but its inner ocean is believed to have existed for billions of years, long enough
for the chemistry of life to evolve. And while there is no evidence of
life on Europa, scientists suggest the moon may have environments
similar to Earth’s deep-ocean hydrothermal vents, where unique
ecosystems thrive despite extreme temperatures and pressures, toxic
minerals and no sunlight.
Observations by NASA’s Hubble Space Telescope in 2012 and 2014 also
suggest water from inside Europa may intermittently vent into space as plumes, similar to what the Cassini spacecraft has observed on
Saturn’s moon Endeladus. Astronomers estimate Europa’s plumes rise
about 125 mi. into space before raining material back down onto the
moon’s surface.
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has
existed for something like four billion years, it supports the general
idea of "random but inevitable"Â theories of Abiogenesis.
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
On Fri, 28 Jun 2024 03:22:04 +0200, "Carlos E.R."
<robin_listas@es.invalid> wrote:
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Our sun is friendly. The universe is deadly.
It's a miracle that Earth is shielded.
Carlos E.R. <robin_listas@es.invalid> wrote:
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Jupiter’s magnetosphere. See e.g. <https://www.science.org/doi/10.1126/sciadv.abd1204>
Carlos E.R. <robin_listas@es.invalid> wrote:
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Jupiter’s magnetosphere. See e.g. ><https://www.science.org/doi/10.1126/sciadv.abd1204>
On 6/28/24 09:01, Jeff Layman wrote:
On 28/06/2024 02:41, john larkin wrote:
On Fri, 28 Jun 2024 03:22:04 +0200, "Carlos E.R."
<robin_listas@es.invalid> wrote:
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures >>>>> on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Our sun is friendly. The universe is deadly.
It's a miracle that Earth is shielded.
Indeed. It's a point often ignored by exoplanet life-seekers. It's one
thing to find suitable conditions which might create life, it's another
thing entirely to find conditions which could sustain life. Take this
very recent review on Gliese 12 b:
<https://ras.ac.uk/news-and-press/news/rare-exo-venus-earth-temperature-discovered>
Note this comment:
"..."Although we don't yet know whether it possesses an atmosphere,
we've been thinking of it as an exo-Venus, with similar size and energy
received from its star as our planetary neighbour in the solar system."
An important factor in retaining an atmosphere is the storminess of its
star. Red dwarfs tend to be magnetically active, resulting in frequent,
powerful X-ray flares.
However, analyses by both teams conclude that Gliese 12 shows no signs
of such extreme behaviour, raising hopes that Gliese 12 b's atmosphere
may still be intact."
So a red dwarf tends to have frequent powerful x-ray flares, yet the
only comment is that there were no signs of this extreme behaviour.
Firstly, how can it be "extreme" if it's frequent, and how long have
they been observing this star anyway? Secondly, did nobody consider what
an x-ray flare would do to any life which might have formed on the
planet? Never mind the planet's surface temperature and presence - or
not - of an atmosphere. A blast of x-rays and probably other radiation
isn't exactly know for its life-sustaining properties.
And that's even supposing a red dwarf would be capable of providing
"suitable" radiation levels capable of supporting an earth-like planet
in the first place. See:
<https://ras.ac.uk/news-and-press/research-highlights/earth-biospheres-other-planets-may-be-rare>
Oh well. Earth has a toxic, oxidizing atmosphere, with free oxygen and
worse, ozone. And yet life thrives.
On 28/06/2024 02:41, john larkin wrote:
On Fri, 28 Jun 2024 03:22:04 +0200, "Carlos E.R."
<robin_listas@es.invalid> wrote:
On 2024-06-27 20:39, Joe Gwinn wrote:
Excerpted from Aviation Week, June 3-16 2024, page 38:
Located more than five times farther away from the Sun than Earth,
Europa seems an unlikely place to look for life. Surface temperatures
on the ice-shrouded moon of Jupiter average |-260F, and radiation
levels are high enough to kill a human being in one day.
Being that far from the sun, where comes that radiation from?
Our sun is friendly. The universe is deadly.
It's a miracle that Earth is shielded.
Indeed. It's a point often ignored by exoplanet life-seekers. It's one
thing to find suitable conditions which might create life, it's another
thing entirely to find conditions which could sustain life. Take this
very recent review on Gliese 12 b: <https://ras.ac.uk/news-and-press/news/rare-exo-venus-earth-temperature-discovered>
Note this comment:
"..."Although we don't yet know whether it possesses an atmosphere,
we've been thinking of it as an exo-Venus, with similar size and energy received from its star as our planetary neighbour in the solar system."
An important factor in retaining an atmosphere is the storminess of its
star. Red dwarfs tend to be magnetically active, resulting in frequent, powerful X-ray flares.
However, analyses by both teams conclude that Gliese 12 shows no signs
of such extreme behaviour, raising hopes that Gliese 12 b's atmosphere
may still be intact."
So a red dwarf tends to have frequent powerful x-ray flares, yet the
only comment is that there were no signs of this extreme behaviour.
Firstly, how can it be "extreme" if it's frequent, and how long have
they been observing this star anyway? Secondly, did nobody consider what
an x-ray flare would do to any life which might have formed on the
planet? Never mind the planet's surface temperature and presence - or
not - of an atmosphere. A blast of x-rays and probably other radiation
isn't exactly know for its life-sustaining properties.
And that's even supposing a red dwarf would be capable of providing "suitable" radiation levels capable of supporting an earth-like planet
in the first place. See: <https://ras.ac.uk/news-and-press/research-highlights/earth-biospheres-other-planets-may-be-rare>
On 6/27/2024 5:17 PM, Don Y wrote:
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has
existed for something like four billion years, it supports the general
idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core.
My guess: The Universe is mammoth, the technological and energy
requirements of even short-distance interstellar travel are immense, the lifespan of technological civilizations is highly time-limited before
such a civilization destroys itself, technological civilizations are
very rare to begin with, and no technological civilization ever survives
long enough to attempt it.
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has
existed for something like four billion years, it supports the general
idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core.
On 6/27/2024 5:17 PM, Don Y wrote:
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has
existed for something like four billion years, it supports the general
idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core.
My guess: The Universe is mammoth, the technological and energy requirements of
even short-distance interstellar travel are immense, the lifespan of technological civilizations is highly time-limited before such a civilization destroys itself, technological civilizations are very rare to begin with, and no technological civilization ever survives long enough to attempt it.
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has
existed for something like four billion years, it supports the general >>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core.
My guess: The Universe is mammoth, the technological and energy requirements of
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >*detect* our presence (given that we seem to make no attempt at "hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >interesting takes on the Fermi paradox.
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>> existed for something like four billion years, it supports the general >>>>> idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at "hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >> interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>> existed for something like four billion years, it supports the general >>>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>*detect* our presence (given that we seem to make no attempt at "hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >>interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Joe Gwinn
On 6/29/2024 8:35 AM, Joe Gwinn wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>> existed for something like four billion years, it supports the
general
idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for >>>>> me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its
core.
My guess: The Universe is mammoth, the technological and energy
requirements of
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a
civilization
destroys itself, technological civilizations are very rare to begin
with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at
"hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_
gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Why does an alien race have to VISIT in order to EXIST?
*We* can't visit anything beyond lunar orbit (perhaps Mars, soon)
yet we expend considerable effort "looking".
What techniques have our deep space probes used /to prevent detection/?
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>> existed for something like four billion years, it supports the general >>>>> idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at "hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >> interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>> existed for something like four billion years, it supports the general >>>>>> idea of "random but inevitable"˙theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe.˙ It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at "hiding") >>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >>> interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Joe Gwinn
An intelligent alien lifeform is probably thousands of light-years
away. Unless they have a Warp Drive, there's no way they would want to
visit us.
A very advanced robot might.
john larkin <jlarkin_highland_tech> wrote:
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:That wouldn't explain why there are no *signs* of intelligent life.
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>>> existed for something like four billion years, it supports the general >>>>>>> idea of "random but inevitable"?ies of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole >>>>>> notion behind an "empty" universe.? a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>>
even short-distance interstellar travel are immense, the lifespan of >>>>> technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it. >>>>
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>>> *detect* our presence (given that we seem to make no attempt at "hiding") >>>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Joe Gwinn
An intelligent alien lifeform is probably thousands of light-years
away. Unless they have a Warp Drive, there's no way they would want to
visit us.
A very advanced robot might.
https://memory-alpha.fandom.com/wiki/V%27ger
Cheers
Phil Hobbs
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
On 2024-06-29 17:35, Joe Gwinn wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>> existed for something like four billion years, it supports the general >>>>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at "hiding") >>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >>> interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
But why can we not detect them, by radio or something? Surely we would
have seen them already.
It is not about visiting.
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>> existed for something like four billion years, it supports the general >>>>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for
me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>>*detect* our presence (given that we seem to make no attempt at "hiding") >>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >>>interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Joe Gwinn
An intelligent alien lifeform is probably thousands of light-years
away. Unless they have a Warp Drive, there's no way they would want to
visit us.
A very advanced robot might.
On 6/29/24 19:11, Don Y wrote:
On 6/29/2024 8:35 AM, Joe Gwinn wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:That wouldn't explain why there are no *signs* of intelligent life.
My guess: The Universe is mammoth, the technological and energyMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>>> existed for something like four billion years, it supports the general >>>>>>> idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole >>>>>> notion behind an "empty" universe. It's a tedious read (mainly for >>>>>> me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>>
requirements of
even short-distance interstellar travel are immense, the lifespan of >>>>> technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it. >>>>
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>>> *detect* our presence (given that we seem to make no attempt at "hiding") >>>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Why does an alien race have to VISIT in order to EXIST?
*We* can't visit anything beyond lunar orbit (perhaps Mars, soon)
yet we expend considerable effort "looking".
What techniques have our deep space probes used /to prevent detection/?
I think we aren't nearly as conspicuous as you think we are. The
deep space probes are tiny. There is not the slightest chance of
finding them without knowing exactly where to look. The very
presence of earth itself is barely noticeable beyond a few
lightyears.
On Sat, 29 Jun 2024 11:26:56 -0700, john larkin
<jlarkin_highland_tech> wrote:
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:That wouldn't explain why there are no *signs* of intelligent life.
My guess: The Universe is mammoth, the technological and energy requirements ofMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>>> existed for something like four billion years, it supports the general >>>>>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole >>>>>> notion behind an "empty" universe. It's a tedious read (mainly for >>>>>> me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>>
even short-distance interstellar travel are immense, the lifespan of >>>>> technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it. >>>>
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>>>*detect* our presence (given that we seem to make no attempt at "hiding") >>>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >>>>interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that >>>which they study.
Joe Gwinn
An intelligent alien lifeform is probably thousands of light-years
away. Unless they have a Warp Drive, there's no way they would want to >>visit us.
The claim being made was that because we were not seeing any
intelligent aliens, they must not exist, or are very rare. Which does
not follow.
A very advanced robot might.
Even if they do have warp drives, they may still send a robot.
But given the technological gulf between Earthlings and any
civilization possessing any warp drive, we won't detect them unless
they want us to.
Joe Gwinn
The claim being made was that because we were not seeing any
intelligent aliens, they must not exist, or are very rare. Which does
not follow.
Even if they do have warp drives, they may still send a robot.
But given the technological gulf between Earthlings and any
civilization possessing any warp drive, we won't detect them unless
they want us to.
On Sat, 29 Jun 2024 17:41:14 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 11:26:56 -0700, john larkin
<jlarkin_highland_tech> wrote:
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net> >>>wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:That wouldn't explain why there are no *signs* of intelligent life.
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>>>> existed for something like four billion years, it supports the general >>>>>>>> idea of "random but inevitable" theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole >>>>>>> notion behind an "empty" universe. It's a tedious read (mainly for >>>>>>> me coming from a non-chinese culture... just keeping track of the >>>>>>> characters is difficult) but has some good ideas to chew on at its core.
My guess: The Universe is mammoth, the technological and energy requirements of
even short-distance interstellar travel are immense, the lifespan of >>>>>> technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it. >>>>>
*We* can't (yet) travel interstellar distances in single lifetimes >>>>>but I'm sure anyone with technology comparable to ours would be able to >>>>>*detect* our presence (given that we seem to make no attempt at "hiding") >>>>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable >>>>of interstellar travel are exceedingly rare, there would be little >>>>reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that >>>>which they study.
Joe Gwinn
An intelligent alien lifeform is probably thousands of light-years
away. Unless they have a Warp Drive, there's no way they would want to >>>visit us.
The claim being made was that because we were not seeing any
intelligent aliens, they must not exist, or are very rare. Which does
not follow.
A very advanced robot might.
Even if they do have warp drives, they may still send a robot.
But given the technological gulf between Earthlings and any
civilization possessing any warp drive, we won't detect them unless
they want us to.
Joe Gwinn
I think that life on Earth is someone's high school science project.
On Sat, 29 Jun 2024 17:41:14 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 11:26:56 -0700, john larkin
<jlarkin_highland_tech> wrote:
On Sat, 29 Jun 2024 11:35:47 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
I think that life on Earth is someone's high school science project.
On 6/29/2024 8:35 AM, Joe Gwinn wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:
Most big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>> existed for something like four billion years, it supports the
general
idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole
notion behind an "empty" universe. It's a tedious read (mainly for >>>>> me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its
core.
My guess: The Universe is mammoth, the technological and energy
requirements of
even short-distance interstellar travel are immense, the lifespan of
technological civilizations is highly time-limited before such a
civilization
destroys itself, technological civilizations are very rare to begin
with, and
no technological civilization ever survives long enough to attempt it.
That wouldn't explain why there are no *signs* of intelligent life.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at
"hiding")
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_
gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Why does an alien race have to VISIT in order to EXIST?
*We* can't visit anything beyond lunar orbit (perhaps Mars, soon)
yet we expend considerable effort "looking".
What techniques have our deep space probes used /to prevent detection/?
On 29/06/2024 18:11, Don Y wrote:
On 6/29/2024 8:35 AM, Joe Gwinn wrote:
On Sat, 29 Jun 2024 04:04:11 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
On 6/28/2024 10:08 PM, bitrex wrote:
On 6/27/2024 5:17 PM, Don Y wrote:That wouldn't explain why there are no *signs* of intelligent life.
My guess: The Universe is mammoth, the technological and energyMost big librarys carry AW.
.<https://europa.nasa.gov/mission/about/>
If it turns out that there is life in the ocean of Europa, which has >>>>>>> existed for something like four billion years, it supports the general >>>>>>> idea of "random but inevitable"Â theories of Abiogenesis.
_Remembrance of Earth's Past_ has an interesting take on the whole >>>>>> notion behind an "empty" universe. It's a tedious read (mainly for >>>>>> me coming from a non-chinese culture... just keeping track of the
characters is difficult) but has some good ideas to chew on at its core. >>>>>
requirements of
even short-distance interstellar travel are immense, the lifespan of >>>>> technological civilizations is highly time-limited before such a civilization
destroys itself, technological civilizations are very rare to begin with, and
no technological civilization ever survives long enough to attempt it. >>>>
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to >>>> *detect* our presence (given that we seem to make no attempt at "hiding") >>>>
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some
interesting takes on the Fermi paradox.
That's a bit self-important.
If the universe is teaming with life, but alien civilizations capable
of interstellar travel are exceedingly rare, there would be little
reason for those spacefaring aliens to visit any but the other
advanced alien civilizations.
We might get the equivalent of an anthropologist ever few million
year, and they would do whatever needed to prevent detection by that
which they study.
Why does an alien race have to VISIT in order to EXIST?
*We* can't visit anything beyond lunar orbit (perhaps Mars, soon)
yet we expend considerable effort "looking".
What techniques have our deep space probes used /to prevent detection/?
Being small insignificant and with feeble radio transmitters. The only reason we are still in contact with the most remote ones is that ground based low noise amplifiers have improved enormously since their launch.
When it was operating and doing radar range imaging the EPR of the Arecibo dish
was phenomenal along the direction it was pointing. Anyone in the beam would see a very distinctive flash potentially with obviously digital patterns in it
if they were lucky.
There have been the odd WOW signal detected on Earth but nothing that stood up
to detailed analysis or was reproducible. The pulsar trace was originally marked LGM in the margins since it's very precise repetitive signal looked artificial at first glance.
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at "hiding")
The Fermi paradox of why aren't they here yet is somewhat tricky to explain. Our star is nothing like the oldest it could be so there are potentially technological societies that are billions of years ahead of us - plenty of time
for robotic probes to visit anywhere in the galaxy.
I suspect that unless there is some clever shortcut using physics we don't yet
know about human inter stellar travel is just a pipe dream.
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some >> interesting takes on the Fermi paradox.
One potentially very interesting way a technological civilisation may be detectable from Earth by spectroscopy is the presence of CFCs and HCFCs in their atmosphere. Once they master fluorine chemistry their discovery and utility is inevitable until they realise the damage to the ozone layer. Then they get phased out. Planets in transit across their suns are now being checked
and so far nothing unusual has been seen.
Key point here is that fluorine is so reactive and calcium so abundant that you
can't really get any fluoro-organic chemistry going without a technological civilisation. A handful of desert plants have mastered it to make monofluoracetic acid on Earth (extremely effective rodenticide).
It takes industrial scale manufacture before CFCs would be visible from afar. SF6 is another common one but it's scale height works against seeing it high in
the atmosphere (its molecule is rather heavy).
But you (we) are still constrained by your knowledge of physical sciences >(and "interstellar civilizations"). Who's to say that "they" haven't >identified some other observable (by THEM) characteristic of civilization?
There are a whole slew of questions that you have to consider before you
even worry about "how" to detect (or signal to) other civilizations.
- how much (effort/cost) do you want to detect them?
- how much do THEY want to be detected?
- how can they evade detection (assuming they actively don't want to be found)?
- how much do YOU want to be found?
- what might the consequences of such a detection be? (e.g., _Remembrance..._ >posits an extinction level consequence)
Adams's claim that "Space is big" can also be accompanied by "Time is LONG". >Do these conspire for or against discovery (or being discovered)?
On a sunny day (Mon, 1 Jul 2024 17:03:32 -0700) it happened Don Y <blockedofcourse@foo.invalid> wrote in <v5vg4n$1a4s7$1@dont-email.me>:
But you (we) are still constrained by your knowledge of physical sciences
(and "interstellar civilizations"). Who's to say that "they" haven't
identified some other observable (by THEM) characteristic of civilization? >>
There are a whole slew of questions that you have to consider before you
even worry about "how" to detect (or signal to) other civilizations.
- how much (effort/cost) do you want to detect them?
- how much do THEY want to be detected?
- how can they evade detection (assuming they actively don't want to be found)?
- how much do YOU want to be found?
- what might the consequences of such a detection be? (e.g., _Remembrance..._
posits an extinction level consequence)
And will our religious fanatic polly-tick-sians and leaders let us know IF life has been detected?
The Mars Viking lander experiment was positive for life.
http://www.gillevin.com/
I remeber the annoucement,
hours later it was plainly denied, experiment never to me mentioned again..
On 02/07/2024 06:25, Jan Panteltje wrote:
On a sunny day (Mon, 1 Jul 2024 17:03:32 -0700) it happened Don Y
<blockedofcourse@foo.invalid> wrote in <v5vg4n$1a4s7$1@dont-email.me>:
But you (we) are still constrained by your knowledge of physical sciences >>> (and "interstellar civilizations"). Who's to say that "they" haven't
identified some other observable (by THEM) characteristic of civilization? >>>
There are a whole slew of questions that you have to consider before you >>> even worry about "how" to detect (or signal to) other civilizations.
- how much (effort/cost) do you want to detect them?
- how much do THEY want to be detected?
- how can they evade detection (assuming they actively don't want to be found)?
- how much do YOU want to be found?
- what might the consequences of such a detection be? (e.g., _Remembrance..._
posits an extinction level consequence)
And will our religious fanatic polly-tick-sians and leaders let us know IF life has been detected?
The Mars Viking lander experiment was positive for life.
http://www.gillevin.com/
I remeber the annoucement,
hours later it was plainly denied, experiment never to me mentioned again..
That was because they realised pretty quickly that what they were seeing
was an inorganic reaction of peroxide and perchlorate ions in the soil
with the nutrients provided. The next generation search for life on Mars
will use stable isotopically labelled materials and stands a pretty good >chance of detecting anything that is alive or nearly so.
There are hints that just maybe something is alive on Venus (unlikely as
this sounds) phosphine has been detected in its atmosphere.
https://www.nytimes.com/2020/09/14/science/venus-life-clouds.html
PS:
This desert moss has the potential to grow on Mars
https://www.sciencedaily.com/releases/2024/06/240630153052.htm
June 30, 2024
Source:
Cell Press
Summary:
The desert moss Syntrichia caninervis is a promising candidate for Mars colonization
thanks to its extreme ability to tolerate harsh conditions lethal to most life forms.
The moss is well known for its ability to tolerate drought conditions,
but researchers now report that it can also survive freezing temperatures as low as 196 C,
high levels of gamma radiation, and simulated Martian conditions involving
these three stressors combined. In all cases, prior dehydration seemed to help the plants cope.
So no problem for plants and plant like lifeforms to grow on mars.
On 7/1/2024 8:43 AM, Martin Brown wrote:
On 29/06/2024 18:11, Don Y wrote:
Why does an alien race have to VISIT in order to EXIST?
*We* can't visit anything beyond lunar orbit (perhaps Mars, soon)
yet we expend considerable effort "looking".
What techniques have our deep space probes used /to prevent detection/?
Being small insignificant and with feeble radio transmitters. The only
reason we are still in contact with the most remote ones is that
ground based low noise amplifiers have improved enormously since their
launch.
Wouldn't you expect other civilizations to also understand the issues involved, if they were interested in searching? We spot bits of
space debris, comets, etc. and they aren't trying to signal their
presence...
When it was operating and doing radar range imaging the EPR of the
Arecibo dish was phenomenal along the direction it was pointing.
Anyone in the beam would see a very distinctive flash potentially with
obviously digital patterns in it if they were lucky.
But they don't have to see a pattern; just an unexpected "event" that attracts their attention. There's a wide field to examine so it seems
they would focus their attentions on anything "unexpected" rather than systematically trying to canvas the entire space.
Assuming "others" have the same technological limits (or abilities!)
as we do is naive.
And, assuming they abandon older technologies to concentrate on
newer ones also seems specious; if lost while hiking, I can signal
with a whistle or a mirror -- I don't have to rely on a cell phone to
get help!
Being small insignificant and with feeble radio transmitters. The only
reason we are still in contact with the most remote ones is that ground
based low noise amplifiers have improved enormously since their launch.
Wouldn't you expect other civilizations to also understand the issues
involved, if they were interested in searching? We spot bits of
space debris, comets, etc. and they aren't trying to signal their
presence...
But we only really spot them when they get near enough to the sun and warm up enough to outgas. Considerable effort now goes into trying to find any and all
Earth crossing asteroids that are big enough to matter and/or might one day be
a threat to our planet.
When it was operating and doing radar range imaging the EPR of the Arecibo >>> dish was phenomenal along the direction it was pointing. Anyone in the beam >>> would see a very distinctive flash potentially with obviously digital
patterns in it if they were lucky.
But they don't have to see a pattern; just an unexpected "event" that
attracts their attention. There's a wide field to examine so it seems
they would focus their attentions on anything "unexpected" rather than
systematically trying to canvas the entire space.
There have been more than one WOW event seen but nothing in the same place twice and most of them have plausible astrophysical signatures.
Seeing a narrow band signal at a non-natural frequency or a modulated one would
be indicative of a civilisation. Pulsars almost fitted the bill at the time they were discovered - tagged LGM in the margin.
Assuming "others" have the same technological limits (or abilities!)
as we do is naive.
They are still limited by the laws of physics as they apply in this universe unless they have found some much deeper understanding. You can put pretty good
bounds on how far away people can watch terrestrial TV from but our planet was
only non-thermal radio bright for less than a century. That is a blink of the eye in cosmological timescales.
Give or take an order of magnitude I expect most civilisations will go through
similar phases of technology to us (unless they are aquatic).
And, assuming they abandon older technologies to concentrate on
newer ones also seems specious; if lost while hiking, I can signal
with a whistle or a mirror -- I don't have to rely on a cell phone to
get help!
Technological civilisations will only be non-thermal radio bright in an easily
detectable way from after they invent AM broadcasting and before they invent spread spectrum UHF services or coax cable or fibre optics.
Interestingly the Austrian actress Hedy Lammar co-invented spread spectrum RF but is mostly remembered for her film roles.
http://www.women-inventors.com/Hedy-Lammar.asp
Somewhat more detail here - her invention helped make allied torpedoes effectively impossible for simple jamming methods to block.
https://www.aps.org/archives/publications/apsnews/201106/physicshistory.cfm
Today it is hard to find anything that isn't spread spectrum and noise like in
appearance unless you have the cryptographic key to unlock it.
Drake has a nice equation where some of the unknowns when he originally wrote it down have now become rather better hard numbers. It turns out that planets around stars are much more common than first thought.
Ones in the Goldilocks zone with all three phases of water are rarer.
On 7/1/2024 7:54 AM, Martin Brown wrote:
*We* can't (yet) travel interstellar distances in single lifetimes
but I'm sure anyone with technology comparable to ours would be able to
*detect* our presence (given that we seem to make no attempt at
"hiding")
The Fermi paradox of why aren't they here yet is somewhat tricky to
explain. Our star is nothing like the oldest it could be so there are
potentially technological societies that are billions of years ahead
of us - plenty of time for robotic probes to visit anywhere in the
galaxy.
And, probes don't ave to "pass through"; there's no reason they can't
sit and watch (if you have advanced technology, what limits might that overcome on designing durable products?)
I suspect that unless there is some clever shortcut using physics we
don't yet know about human inter stellar travel is just a pipe dream.
But you don't need to *go* somewhere to know that it exists *or* what
it is like. We've visited Mars without ever having set foot, there.
Ditto the depths of the oceans.
We can make educated assessments as to the suitability for "life"
in places that we could never expect to actually visit. Or,
discover some form of life and then set upon trying to sort out how
to communicate with same.
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_[snip]
gives some
interesting takes on the Fermi paradox.
It takes industrial scale manufacture before CFCs would be visible
from afar. SF6 is another common one but it's scale height works
against seeing it high in the atmosphere (its molecule is rather heavy).
But you (we) are still constrained by your knowledge of physical sciences (and "interstellar civilizations"). Who's to say that "they" haven't identified some other observable (by THEM) characteristic of civilization?
There are a whole slew of questions that you have to consider before you
even worry about "how" to detect (or signal to) other civilizations.
- how much (effort/cost) do you want to detect them?
- how much do THEY want to be detected?
- how can they evade detection (assuming they actively don't want to be found)?
- how much do YOU want to be found?
- what might the consequences of such a detection be? (e.g., _Remembrance..._
posits an extinction level consequence)
Adams's claim that "Space is big" can also be accompanied by "Time is
LONG".
Do these conspire for or against discovery (or being discovered)?
On 02/07/2024 01:03, Don Y wrote:
On 7/1/2024 7:54 AM, Martin Brown wrote:
*We* can't (yet) travel interstellar distances in single lifetimesThe Fermi paradox of why aren't they here yet is somewhat tricky to explain.
but I'm sure anyone with technology comparable to ours would be able to >>>> *detect* our presence (given that we seem to make no attempt at "hiding") >>>
Our star is nothing like the oldest it could be so there are potentially >>> technological societies that are billions of years ahead of us - plenty of >>> time for robotic probes to visit anywhere in the galaxy.
And, probes don't ave to "pass through"; there's no reason they can't
sit and watch (if you have advanced technology, what limits might that
overcome on designing durable products?)
It still puts quite hard limits on how small a device can observe the Earth even with diffraction limited optics. Monitoring radio traffic is much easier if the frequency is such that it escapes.
I suspect that unless there is some clever shortcut using physics we don't >>> yet know about human inter stellar travel is just a pipe dream.
But you don't need to *go* somewhere to know that it exists *or* what
it is like. We've visited Mars without ever having set foot, there.
Ditto the depths of the oceans.
Indeed and remote sensing is getting very good now. I expect that someone will
find a planet with evidence of an industrial atmosphere within the next century
or so (maybe sooner).
We can make educated assessments as to the suitability for "life"
in places that we could never expect to actually visit. Or,
discover some form of life and then set upon trying to sort out how
to communicate with same.
That can be fraught with difficulties. I expect life as reproducing photosynthetic slime is extremely common anywhere that is stable enough to allow a billion years of reactions. Aqueous environment might not be strictly necessary but most other things have solid phases that sink.
_If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?_ gives some[snip]
interesting takes on the Fermi paradox.
It takes industrial scale manufacture before CFCs would be visible from
afar. SF6 is another common one but it's scale height works against seeing >>> it high in the atmosphere (its molecule is rather heavy).
But you (we) are still constrained by your knowledge of physical sciences
(and "interstellar civilizations"). Who's to say that "they" haven't
identified some other observable (by THEM) characteristic of civilization?
They may have done but there are still hard limits on how big an antenna must be to obtain signal that is above the background noise floor.
There are a whole slew of questions that you have to consider before you
even worry about "how" to detect (or signal to) other civilizations.
- how much (effort/cost) do you want to detect them?
- how much do THEY want to be detected?
- how can they evade detection (assuming they actively don't want to be found)?
- how much do YOU want to be found?
- what might the consequences of such a detection be? (e.g., _Remembrance..._
posits an extinction level consequence)
Encounters between species with advanced technology don't usually end well for
the ones still in the iron age when they come up against automatic weapons. If
we ever meet alien space travellers we had better hope that they are friendly.
Even so their advanced technology could wreak unintentional havoc.
Adams's claim that "Space is big" can also be accompanied by "Time is LONG". >> Do these conspire for or against discovery (or being discovered)?
Space is mind bogglingly *BIG* the gaps between stars are huge.
The only place where stars are close together are in globular clusters and in environment so odd that it is probably one of the places where you can pretty much rule out life evolving. Close three body encounters happen often enough to
lob whole stars out at very high speed and leave the remaining ones ever more tightly bound. They are extremely pretty.
Arecibo's first ever deliberate message was sent to M13 it will take about 25k
years to get there and another 25k for a reply if the intended recipients happen to notice it. Chances are there is no-one there.
https://en.wikipedia.org/wiki/Arecibo_message
I reckon in 50k years +/- 500 no one on Earth will even remember that the message was sent.
https://en.wikipedia.org/wiki/Messier_13#/media/File:Messier_13.jpg
Just naked eye as a faint fuzzy blob under Hercules right shoulder - more obvious in binoculars (visible in summer).
Worth seeing first hand in a 15" scope or larger.
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 415 |
Nodes: | 16 (2 / 14) |
Uptime: | 93:13:37 |
Calls: | 8,690 |
Calls today: | 5 |
Files: | 13,250 |
Messages: | 5,947,022 |