# 8557 bylucioc@... on July 20, 2006, 2:09 p.m.
Member since 2021-10-03
http://www.space.com/searchforlife/seti_thursday_060720.html
What the people mentioning the Fermi paradox say is that, if the
galaxy is swarming with hundreds of thousands of alien civilizations
as the Drake Equation says, then it would be highly unlikely that at
least one of those civilization's would't be able to develop sublight
interstellar travel and colonize the whole galaxy in an "eyeblink" -
just a few million years at most. So the parallel of the author is
invalid: looking for an specific species - elephants - in the parking
lot is akin to looking for a specific sentient alien species (say,
Vulcans or Kryptonians ;-) in SETI. Then, since we are looking for
*any* sentient alien species, the correct parking lot analogy would be
to look for *any* living species in the parking lot. And I am sure
that at any time that he checks the parking lot he can see birds,
insects and perhaps even stray cats and dogs, and therefore correctly
infer that there are other living species around...
# 8558 bymikecombs@... on July 20, 2006, 2:43 p.m.
Member since 2021-10-03
You are of course spot on. The best analogy is to claim that the fact we can find no bacteria in the parking lot doesn't mean there aren't bacteria elsewhere. But the reality is that bacteria quickly spread to fill every available ecological niche; and there just aren't that many spots on earth which don't qualify as an ecological niche for them. The inevitable consequence of the combination of self-replication and a rich growth media is massive colonization.
Regards,
Mike Combs
From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com] On Behalf Of Lucio de Souza Coelho
Sent: Thursday, July 20, 2006 9:08 AM
To: spacesettlers@yahoogroups.com
Subject: [spacesettlers] SETI again
http://www.space.com/searchforlife/seti_thursday_060720.html
Actually, in item #2 the author is using the fallacy of undue analogy.
What the people mentioning the Fermi paradox say is that, if the galaxy is swarming with hundreds of thousands of alien civilizations as the Drake Equation says, then it would be highly unlikely that at least one of those civilization's would't be able to develop sublight interstellar travel and colonize the whole galaxy in an "eyeblink" - just a few million years at most. So the parallel of the author is
invalid: looking for an specific species - elephants - in the parking lot is akin to looking for a specific sentient alien species (say, Vulcans or Kryptonians ;-) in SETI. Then, since we are looking for
*any* sentient alien species, the correct parking lot analogy would be to look for *any* living species in the parking lot. And I am sure that at any time that he checks the parking lot he can see birds, insects and perhaps even stray cats and dogs, and therefore correctly infer that there are other living species around...
# 8559 byjoe@... on July 20, 2006, 4:48 p.m.
Member since 2021-10-03
On Jul 20, 2006, at 14:08 UTC, Lucio_de_Souza_Coelho wrote:
>
> Actually, in item #2 the author is using the fallacy of undue analogy.
> What the people mentioning the Fermi paradox say is that, if the
> galaxy is swarming with hundreds of thousands of alien civilizations
> as the Drake Equation says, then it would be highly unlikely that at
> least one of those civilization's would't be able to develop sublight
> interstellar travel and colonize the whole galaxy in an "eyeblink" -
> just a few million years at most.
Right. Because interstellar travel is possible, the Drake equation is complete and utter nonsense. This is not surprising, since Drake was an astronomer, not a biologist -- but any biologist (or anyone with even a passing familiarity with population dynamics, for that matter) would immediately recognize it as utter nonsense, and I'm astonished that otherwise intelligent people continue to trot it out as if it means something.
The reason it's nonsense is that it is a static equation. But population dynamics are not static; they are, er, dynamic. You hit the nail on the head above: as soon as a civilization develops interstellar travel, it has available to it an enormous new niche (i.e. the rest of the galaxy). New niches do NOT stay uncolonized once they become available; population grows exponentially until the limit is mostly filled and resources again start to become scarce.
To describe this algebraically would require a differential equation (or if you prefer, a function of time).
> So the parallel of the author is
> invalid: looking for an specific species - elephants - in the parking
> lot is akin to looking for a specific sentient alien species (say,
> Vulcans or Kryptonians ;-) in SETI. Then, since we are looking for
> *any* sentient alien species, the correct parking lot analogy would be
> to look for *any* living species in the parking lot. And I am sure
> that at any time that he checks the parking lot he can see birds,
> insects and perhaps even stray cats and dogs, and therefore correctly
> infer that there are other living species around...
Yes, you're quite right on that point too. We don't care what alien life we find; but if any spacefaring civilizations are out there at all, then they should be pretty much *everywhere*, just as life is everywhere on Earth, even though a particular species may not be.
Best,
- Joe
Joe Strout -- joe@...
# 8560 byxenophile2002@... on July 20, 2006, 9:05 p.m.
Member since 2021-10-03
Hi. I'm an Australian Aborigine in the year 1500. And I can't help
but wonder: If there are people beyond Australia, where are they?
# 8561 byhetrevillion@... on July 20, 2006, 9:45 p.m.
Member since 2021-10-03
They are at Alpha Centauri.
Xenophile wrote: Hi. I'm an Australian Aborigine in the year 1500. And I can't help
but wonder: If there are people beyond Australia, where are they?
# 8562 bylucioc@... on July 20, 2006, 9:50 p.m.
Member since 2021-10-03
On 7/20/06, Xenophile wrote:
(...)
> Hi. I'm an Australian Aborigine in the year 1500. And I can't help
> but wonder: If there are people beyond Australia, where are they?
(...)
bug-eyed aliens entering the Solar System next Tuesday is a
possibility, and *then* we will finally have ground-truth evidence as
the Australians had after some time ;-). (Or, who knows, perhaps the
aliens are already here, as Mike suggests in his story Eyes, Shining
Back from the Dark - http://members.aol.com/howiecombs/eyeshine.htm .)
Or, extending the Australian analogy, the aliens in fact will be
the... Refugees from the 12 Colonies running away from Cylons! ;-)
Pre-contact Australians, on the other hand, probably did not have a
very accurate notion of continent-scale Australian geography. It is
likely that they didn't even know that they were in a big piece of
land surrounded by ocean.
However, Old Worlders knew since pre-Christian times that Earth was a
really big ball, and the mapped surface that they had at hand at the
time was just a fraction of the total surface of this sphere. This
lead them to hypothesize that there were other lands with strange
peoples out there in those unknown regions - that is what Swift did in
Gulliver's adventures and Thomas More in The Utopia. Both authors also
concluded - correctly, as time would show - that if there were other
peoples out they had not show up yet, then those peoples necessarily
had no long-range navigation technology.
Now, in terms of cosmic colonization, will we be in the colonizer or
in the coloniz*ed* side?
# 8563 bydehammer@... on July 20, 2006, 10:35 p.m.
Member since 2021-10-03
im afraid you might be a little off on your time scale. Galileo and
his compatriots were demonized by the church for saying the earth was
round and that it was not the center of the universe. all of this was
well after christ.
wrote:
>
> On 7/20/06, Xenophile wrote:
> (...)
> > Hi. I'm an Australian Aborigine in the year 1500. And I can't
help
> > but wonder: If there are people beyond Australia, where are they?
> (...)
>
> Nobody is denying that a habitat packed with godless communist
> bug-eyed aliens entering the Solar System next Tuesday is a
> possibility, and *then* we will finally have ground-truth evidence
as
> the Australians had after some time ;-). (Or, who knows, perhaps the
> aliens are already here, as Mike suggests in his story Eyes, Shining
> Back from the Dark -
http://members.aol.com/howiecombs/eyeshine.htm .)
> Or, extending the Australian analogy, the aliens in fact will be
> the... Refugees from the 12 Colonies running away from Cylons! ;-)
>
> Pre-contact Australians, on the other hand, probably did not have a
> very accurate notion of continent-scale Australian geography. It is
> likely that they didn't even know that they were in a big piece of
> land surrounded by ocean.
>
> However, Old Worlders knew since pre-Christian times that Earth was
a
> really big ball, and the mapped surface that they had at hand at the
> time was just a fraction of the total surface of this sphere. This
> lead them to hypothesize that there were other lands with strange
> peoples out there in those unknown regions - that is what Swift did
in
> Gulliver's adventures and Thomas More in The Utopia. Both authors
also
# 8564 bydehammer@... on July 20, 2006, 10:32 p.m.
Member since 2021-10-03
we cant find evidence of them, they must not exist.
# 8565 bylucioc@... on July 20, 2006, 11:32 p.m.
Member since 2021-10-03
On 7/20/06, Robert wrote:
(...)
> im afraid you might be a little off on your time scale. Galileo and
> his compatriots were demonized by the church for saying the earth was
> round and that it was not the center of the universe. all of this was
> well after christ.
(...)
The accusations (it never got to demonization) against Galileo
concerned his heliocentric model, not the fact that the Earth is
round. As for time scales, the first person in recorded history to
compute Earth's circumference was Eratosthenes, who lived during the
third and second centuries *before* Christ
(http://en.wikipedia.org/wiki/Eratosthenes). And a century before him
Aristotle gathered qualitative evidence (like different stars visible
from different places far enough) to support the spherical Earth
theory. Anyhow, apparently the hypothesis was first proposed by
Pythagoras three centuries before Aristotle, although he formulated it
based on purely aesthetic grounds.
However, it is true that during most of History only highly educated
people (including Galileo and the High Clergy) knew about the
sphericity of the Earth; the largest part of the population believed
on a flat earth. And nowadays I find that *even* many "highly educated
people" have difficult to understand how Earth can be spherical and
have no edge from where people fall in space. 8-(
# 8566 bydougmay@... on July 21, 2006, 12:15 a.m.
Member since 2021-10-03
On Jul 20, 2006, at 5:35 PM, Robert wrote:
> his compatriots were demonized by the church for saying the earth was
> round and that it was not the center of the universe. all of this was
> well after christ.
The Ancient Greeks figured out the Earth was spherical based on the
fact that ships sink as they cross the horizon, instead of shrink to
a dot, and that the Earth always cast a round shadow on the moon
during an eclipse, no matter the angle. That idea was not seriously
challenged by scholars, except an occasional weirdo, although most
people (common and royal) of course were not scholars and believed
in all kinds of weird things, including flat Earths. Many stories
like the Odyssey and others talk of strange lands and creatures that
obviously must be out there somewhere.
Galileo was charged with heresy for claiming the Earth was not the
center of the universe, which somehow, according to the Church,
denied the power of God.
As "enlightened" as we are today, it is frightening how many people
want roll back all these truths we have discovered and return us to
an age where a powerful Church gets to define God and His creation by
spinning lies any which way they want. We are perilously close to
another dark age right now, I fear, and I am VERY anxious to get self-
sufficient, reproducible space colonies out there before this "do as
I say God says" crowd saps the light right out of us. Then it might
take a few hundred years to get the ball rolling again.
doug "the occasional pessimist"
# 8567 bydehammer@... on July 21, 2006, 1:07 a.m.
Member since 2021-10-03
ok some believed it, but just look at how much trouble Columbus had
in conviencing anyone in the 1400's that the world was round.
everyone still said you fell off the earth if you went to far away
from land.
>
> On Jul 20, 2006, at 5:35 PM, Robert wrote:
>
> > im afraid you might be a little off on your time scale. Galileo
and
> > his compatriots were demonized by the church for saying the earth
was
> > round and that it was not the center of the universe. all of this
was
> > well after christ.
>
> The Ancient Greeks figured out the Earth was spherical based on
the
> fact that ships sink as they cross the horizon, instead of shrink
to
> a dot, and that the Earth always cast a round shadow on the moon
> during an eclipse, no matter the angle. That idea was not
seriously
> challenged by scholars, except an occasional weirdo, although most
> people (common and royal) of course were not scholars and
believed
> in all kinds of weird things, including flat Earths. Many stories
> like the Odyssey and others talk of strange lands and creatures
that
> obviously must be out there somewhere.
>
> Galileo was charged with heresy for claiming the Earth was not the
> center of the universe, which somehow, according to the Church,
> denied the power of God.
>
> As "enlightened" as we are today, it is frightening how many
people
> want roll back all these truths we have discovered and return us
to
> an age where a powerful Church gets to define God and His creation
by
> spinning lies any which way they want. We are perilously close to
> another dark age right now, I fear, and I am VERY anxious to get
self-
> sufficient, reproducible space colonies out there before this "do
as
> I say God says" crowd saps the light right out of us. Then it
might
# 8568 bylucioc@... on July 21, 2006, 3:14 a.m.
Member since 2021-10-03
On 7/20/06, Robert wrote:
(...)
> ok some believed it, but just look at how much trouble Columbus had
> in conviencing anyone in the 1400's that the world was round.
cartoon were a comical Columbus is portrayed trying to convince the
Spanish king), Earth sphericity was not the problem in Columbus
theories.
The problem was that Columbus used calculations from an ancient
Phoenician from the 1st century before Christ, Marinus of Tyre, which
postulated that landmasses occupied two-thirds of Earth circumference,
and also misconverted measurements of Earth circumference from the
writings of a Persian astronomer from the 9th Century AD, Al-Farghani.
As a result, the Earth imagined by Columbus was 25,000 Km in
circumference, almost half of the actual size of Earth (more
Mars-sized than Earth sized) and mostly covered by land instead of
oceans. However, most of the geographers and astronomers of the time
agreed upon a circumference close to the real value of 40,000 Km and
(taking apart fictional works like the Divine Comedy) assumed that
there was nothing else but water in the rest of the world. In such a
situation, trying to cross an ocean that big seemed a temerity, and it
was simply natural to find that Columbus was a lunatic sloppy with his
calculations - and yes, that was precisely what he was ;-).
In fact, even the Spanish crown probably saw Columbus as a demented
navigator, but they were hopeful that he would find some unknown
islands during his folly. (After all, the Portuguese had discovered
many new islands in the 15th Century.) It turns out that they were
lucky and Columbus found another group of continents. (Even though he
died thinking that the Americas were in fact Asia.)
> everyone still said you fell off the earth if you went to far away
> from land.
(...)
Actually, the prevalent theory of gravity (again developed by ancient
Greeks, and in parallel by ancient Hindus) among educated people at
the time said that objects have a tendency to fall towards the ground.
if Earth is spherical, then the ground is also curved and what is "up"
in some point of Earth maybe "down" from some other point. An example
of this notion among educated people is in the aforementioned Dante's
Divine Comedy. In the book Dante travels through the center of Earth
(yes, Jules Verne was not that innovative ;-) and emerges in the
antipode, in the then-unknown Southern Hemisphere, were he finds the
Purgatory, which was an island inhabited by the ghosts of the
recently deceased. However, the Purgatory is not described as "upside
down" and the ocean stays were it should be, over the ground (or,
saying better, over the ocean floor). As a side note, Dante probably
imagined the shortcut through the center of the Earth because Saint
Augustine wrote in the 4th or 5th century that it would be
"impossible" to cross any vastness of sea that separated the known
lands from any hypothetical unknown land that might exist in the
Antipodes.
# 8569 bydehammer@... on July 21, 2006, 5:21 a.m.
Member since 2021-10-03
actually i was going with what was taught it school, and that was
that they believe the earth was flat and there were demons and
monsters and such that would kill and eat any crew that strayed too
far from land. of course, it would not be the first time that schools
teach the wrong thing. In America, they did once upon a time teach
that there was no evolution and a'white men were men and black men
were animals'. both fallacies have long since stopped being taught
and the beliefs of the europeans could have been fixed since i went
to school. I always had something of a problem with it.
wrote:
>
> On 7/20/06, Robert wrote:
> (...)
> > ok some believed it, but just look at how much trouble Columbus
had
> > in conviencing anyone in the 1400's that the world was round.
>
> Although popular belief holds that (perhaps due to that Bugs Bunny
> cartoon were a comical Columbus is portrayed trying to convince the
> Spanish king), Earth sphericity was not the problem in Columbus
> theories.
>
> The problem was that Columbus used calculations from an ancient
> Phoenician from the 1st century before Christ, Marinus of Tyre,
which
> postulated that landmasses occupied two-thirds of Earth
circumference,
> and also misconverted measurements of Earth circumference from the
> writings of a Persian astronomer from the 9th Century AD, Al-
Farghani.
> As a result, the Earth imagined by Columbus was 25,000 Km in
> circumference, almost half of the actual size of Earth (more
> Mars-sized than Earth sized) and mostly covered by land instead of
> oceans. However, most of the geographers and astronomers of the time
> agreed upon a circumference close to the real value of 40,000 Km and
> (taking apart fictional works like the Divine Comedy) assumed that
> there was nothing else but water in the rest of the world. In such a
> situation, trying to cross an ocean that big seemed a temerity, and
it
> was simply natural to find that Columbus was a lunatic sloppy with
his
> calculations - and yes, that was precisely what he was ;-).
>
> In fact, even the Spanish crown probably saw Columbus as a demented
> navigator, but they were hopeful that he would find some unknown
> islands during his folly. (After all, the Portuguese had discovered
> many new islands in the 15th Century.) It turns out that they were
> lucky and Columbus found another group of continents. (Even though
he
> died thinking that the Americas were in fact Asia.)
>
> > everyone still said you fell off the earth if you went to far
away
> > from land.
> (...)
>
> Actually, the prevalent theory of gravity (again developed by
ancient
> Greeks, and in parallel by ancient Hindus) among educated people at
> the time said that objects have a tendency to fall towards the
ground.
> if Earth is spherical, then the ground is also curved and what
is "up"
> in some point of Earth maybe "down" from some other point. An
example
> of this notion among educated people is in the aforementioned
Dante's
> Divine Comedy. In the book Dante travels through the center of Earth
> (yes, Jules Verne was not that innovative ;-) and emerges in the
> antipode, in the then-unknown Southern Hemisphere, were he finds the
> Purgatory, which was an island inhabited by the ghosts of the
> recently deceased. However, the Purgatory is not described
as "upside
# 8570 bymikecombs@... on July 21, 2006, 1:02 p.m.
Member since 2021-10-03
From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Xenophile
> And I can't help but wonder: If there are people
> beyond Australia, where are they?
But to make your analogy work, you had to be specific with regard to
year, placing it at a very early era in oceanic exploration. The
problem is that there's no particular reason to assume that every other
civilization in the galaxy is at a very early era in interstellar
exploration. We can't rule out civilizations which have had
interstellar travel for the last million years.
Regards,
Mike Combs
# 8571 bylucioc@... on July 21, 2006, 2:08 p.m.
Member since 2021-10-03
On 7/21/06, Robert wrote:
(...)
> actually i was going with what was taught it school, and that was
> that they believe the earth was flat and there were demons and
> monsters and such that would kill and eat any crew that strayed too
> far from land. of course, it would not be the first time that schools
> teach the wrong thing. In America, they did once upon a time teach
> that there was no evolution and a'white men were men and black men
> were animals'. both fallacies have long since stopped being taught
> and the beliefs of the europeans could have been fixed since i went
> to school. I always had something of a problem with it.
(...)
world were there are lazy teachers that like to oversimplify
everything or are simply ignorant and really don't know what they
"teach". I remember a Geography teacher when I was 15 yo who made the
astounding statement that the movements of the planets had "no known
explanation to Science". I think that he believed that the planets
were maintained in their orbits by magic or God's will. And that 300
years after Newton! 8-.
# 8572 byjoe@... on July 21, 2006, 2:58 p.m.
Member since 2021-10-03
On Jul 20, 2006, at 21:05 UTC, Xenophile wrote:
> but wonder: If there are people beyond Australia, where are they?
That's an invalid analogy, because all people got started at the same time. Sure, if all civilizations in the galaxy got started at the same time, then it would be quite reasonable to imagine that we're all at a pretty close level of development, and there would be thousands of civilizations out there who had not yet colonized the whole galaxy -- just like Star Trek.
But real life is not like Star Trek. Any natural process involving lots of random-ish variables ends up following a normal distribution. We know it took us about 4 billion years to appear on Earth, so we're talking about a distribution with a mean measured in billions of years. Unless the standard deviation is ridiculously, unbelievably small, that means that the first civilizations arose billions of years before the average. And as I'm sure you know, it only takes a few hundred million years for the first civilization to colonize the galaxy. (And this is ignoring the fact that some stars are much older than ours, which would make the argument even stronger.)
The closest your analogy could get to accuracy would be: I'm an Australian aborigine in the year 4000. Am I still wondering about life outside of Australia?
Best,
- Joe
>
Joe Strout -- joe@...
# 8573 byjoe@... on July 21, 2006, 3:01 p.m.
Member since 2021-10-03
On Jul 20, 2006, at 22:32 UTC, Robert wrote:
No, it's: if they existed, some of them would be much older than us, and would have colonized the entire galaxy long ago, in which case either (a) they would be patently obvious, or (b) they would be hiding from us. Since we can't find evidence of them, (a) is clearly not the case. So either they don't exist, or they are purposely hiding themselves. (Either way, SETI will continue to fail.)
Best,
- Joe
Joe Strout -- joe@...
# 8574 byjoe@... on July 21, 2006, 3:11 p.m.
Member since 2021-10-03
On Jul 21, 2006, at 05:20 UTC, Robert wrote:
> that they believe the earth was flat and there were demons and
> monsters and such that would kill and eat any crew that strayed too
> far from land. of course, it would not be the first time that schools
> teach the wrong thing.
Yes, I'm afraid you were done a disservice. All the educated (including the royalty) knew perfectly well the Earth was round, and how big it was. It was Columbus who was wrong: he thought it was much smaller than it really was, and that he could make it all the way to Asia by sailing west. He managed to convince the Spanish to let him try, because they were desperate to get an edge over the Portugese. Fortunately for Columbus, he got lucky and ran into the Americas just before he ran out of provisions. Had there been nothing but open ocean between Europe and Asia, as they had believed, Columbus and his crew would indeed have been lost.
Not that this has much to do with space settlement, but...
Best,
- Joe
Joe Strout -- joe@...
# 8575 bydehammer@... on July 21, 2006, 3:34 p.m.
Member since 2021-10-03
someone has to be the first race. we cant rule out that we are the
first. also we cant rule out that if there is one faster, that it is
so far away the evidence of it will not reach us for a million years.
>
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Xenophile
>
> > Hi. I'm an Australian Aborigine in the year 1500.
> > And I can't help but wonder: If there are people
> > beyond Australia, where are they?
>
> But to make your analogy work, you had to be specific with regard to
> year, placing it at a very early era in oceanic exploration. The
> problem is that there's no particular reason to assume that every
other
# 8576 bydehammer@... on July 21, 2006, 3:41 p.m.
Member since 2021-10-03
that was something my teacher never was willing to discuss. there was
a story of a greek that looked down two wells at the same time of day
and came up with a compairatively accuract size of the earth, then
several hundred years later, they are suppose to believe the earth is
flat? it never made since to me. does now though. thanks.
then tie it to the ground because it would make electicity that
way!!! lol.
--- In spacesettlers@yahoogroups.com, joe@... wrote:
>
> On Jul 21, 2006, at 05:20 UTC, Robert wrote:
>
> > actually i was going with what was taught it school, and that was
> > that they believe the earth was flat and there were demons and
> > monsters and such that would kill and eat any crew that strayed
too
> > far from land. of course, it would not be the first time that
schools
> > teach the wrong thing.
>
> Yes, I'm afraid you were done a disservice. All the educated
(including the royalty) knew perfectly well the Earth was round, and
how big it was. It was Columbus who was wrong: he thought it was
much smaller than it really was, and that he could make it all the
way to Asia by sailing west. He managed to convince the Spanish to
let him try, because they were desperate to get an edge over the
Portugese. Fortunately for Columbus, he got lucky and ran into the
Americas just before he ran out of provisions. Had there been
nothing but open ocean between Europe and Asia, as they had believed,
Columbus and his crew would indeed have been lost.
# 8577 bydougmay@... on July 21, 2006, 4:57 p.m.
Member since 2021-10-03
On Jul 21, 2006, at 10:33 AM, Robert wrote:
> first. also we cant rule out that if there is one faster, that it is
> so far away the evidence of it will not reach us for a million years.
My completely unfounded theory (guess) is this:
1. The first few billion years there were not enough heavy elements
and there was too much cosmic radiation, so life didn't stand a
chance until 4 or 5 billion years ago, so there are likely to be few
or no civilizations billions of years older than ours, though there
still could be some millions of years older.
2. Our sun is much warmer and more radioactive than most. Hotter
stars don't last long enough for life to develop. Smaller, cooler
( I.E. most) stars would require planets to be much closer to their
sun for water to exist as liquid. An average star's habitable zone is
well within the solar flare zone, and also deep within the stars
gravity well, causing the planet to be tidally locked (like our moon
is to us) and moonless. (I suspect they will be moonless because the
immense gravity of the sun at that close distance would pull all
would be moons in). These conditions would not preclude life on these
star systems, but it makes complex evolution occur more slowly. In
our system, by contrast, where our habitable zone is a safer distance
from our star, we are protected by a strong magnetic field that not
all planets possess. Without that magnetic field, Life would have
been ripped to shreds by our powerful sun's radiation. Again, this
wouldn't preclude life from forming, but probably would have
prevented large, complex organisms from evolving. So we are lucky to
next to a powerful star with a planet that protects us from it.
Astronomers may soon be able to start taking inventories of
extrasolar planets and confirm or refute this theory (guess) of mine.
3. People often measure a civilization's beginning from the time they
learned to write or even the time they learned space flight, but in
galactic terms, I think it is more useful to measure a civilization's
beginning from the moment of their first identifiable ancestor, which
makes our civ about 3 or 4 billion years old. We are, each of us,
the very first organism on Earth. We've just been subdividing,
mutating, and swapping genetic information for billions of years, but
we're all the same creature. How many times did our civ sit here for
millions of years at a time with no major evolutionary changes? Most
of the time. In fact, there has been surprisingly little change in
the last 500 million years. Individual species come and go, and most
of the megafauna disappeared around 10,000 years ago, but nearly
every species on Earth today had a equivalent around back then, with
"intelligent" man being a noteworthy exception. Evolution is driven
by isolation and crisis, not by a calendar. It should come as no
surprise that other civilizations are sitting out there at lesser
stages of development, awaiting some crisis to drive their evolution
onward.
There are, I believe, millions of civilizations out there, at various
stages of development. Life on Earth has been just dangerous enough
to drive our evolution at a blindingly fast rate, but not dangerous
enough to destroy us. yet. Despite the long odds, I would not be
surprised at all to someday encounter a spacefaring civilization at
approximately the same level of advancement as us. Except, since they
don't have NASA, they likely will not have Tang and velcro.
doug "4 billion years old and counting"
# 8578 byxenophile2002@... on July 21, 2006, 5:09 p.m.
Member since 2021-10-03
Columbus found land on the exact day that he predicted that he would.
He had good relations with the Vatican, and the Vatican knew about
Vinland. Columbus visited Ireland and learned of the legend of Saint
Brendan. And so on.
and assumed it was Asia, which meant that the Earth must be smaller
than the experts thought, which meant...
# 8579 byjoe@... on July 21, 2006, 7:36 p.m.
Member since 2021-10-03
On Jul 21, 2006, at 15:33 UTC, Robert wrote:
> first.
Of course. That boils down to the "there's nobody else out there" answer, and makes sense only if the evolution of technological life is exceedingly rare and difficult.
In my opinion, that is one of only two reasonable possibilities (the other being that we're in some sort of nature preserve, and our keepers will clearly introduce themselves when they're good and ready).
> also we cant rule out that if there is one faster, that it is
> so far away the evidence of it will not reach us for a million years.
We pretty much can. If we're not the first, then probably whoever was first was at least millions of years ahead of us -- more likely billions. They would have had plenty of time to colonize the whole galaxy by now.
I did some detailed calculations on this a while back and found that, under certain generous assumptions, it was just possible for 2 or 3 civilizations (of billions that would eventually evolve) to achieve spaceflight before the first one filled up the galaxy. But it was unlikely; far more common is for the first one to be considerably ahead of civ #2. This is because at the tail ends of a normal distribution, individuals tend to be quite far apart.
Best,
- Joe
Joe Strout -- joe@...
# 8580 byjoe@... on July 21, 2006, 7:45 p.m.
Member since 2021-10-03
On Jul 21, 2006, at 16:57 UTC, Douglas May wrote:
> and there was too much cosmic radiation, so life didn't stand a
> chance until 4 or 5 billion years ago, so there are likely to be few
> or no civilizations billions of years older than ours, though there
> still could be some millions of years older.
Even if you assume nobody can get started until, say, 4 billion years ago -- which seems unlikely to me -- this argument still doesn't hold, if we assume (as we should, in the absence of contrary evidence) that our history is average. In that case, a normal distribution with a mean of 4 billion years, and a reasonable standard deviation of say a billion years (or even half a billion), would in a population as big as our Galaxy result in quite a few outliers developing 2 billion years ago or more.
> 2. Our sun is much warmer and more radioactive than most...
There are lots of reasons why our planet may be uniquely conducive to life. See the book "Rare Earth".
> 3. People often measure a civilization's beginning from the time they
> learned to write or even the time they learned space flight, but in
> galactic terms, I think it is more useful to measure a civilization's
> beginning from the moment of their first identifiable ancestor, which
> makes our civ about 3 or 4 billion years old.
I think you need a different word for "civilization" for it then. How about "proto-civilization." Civilization didn't start on Earth until something like 40,000 years ago. The dinosaurs ruled for many millions of years but never developed any civilization at all, as far as we can tell.
> It should come as no surprise that other civilizations are sitting
> out there at lesser stages of development, awaiting some crisis to
> drive their evolution onward.
Those are not civilizations, as everyone else in this topic uses the word. Those would be planets with life, and I agree, there may be many of them. But none of them have reached the point where cultural evolution outstrips genetic evolution, since once they do (i.e., once a civilization forms), they'll either die out or colonize the galaxy relatively quickly.
> Despite the long odds, I would not be
> surprised at all to someday encounter a spacefaring civilization at
> approximately the same level of advancement as us.
Then I think you haven't really contemplated how long the odds are. I would be astonished, since if you do the math, you find that such a situation is nearly impossible. (Except of course for all the average civilizations, all of whom would find themselves in a galaxy long since settled by old-timers billions of years ago.)
Best,
- Joe
Joe Strout -- joe@...
# 8581 bymikecombs@... on July 21, 2006, 8:07 p.m.
Member since 2021-10-03
From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of joe@...
>
> > Despite the long odds, I would not be surprised at all to someday
> > encounter a spacefaring civilization at approximately the same level
> > of advancement as us.
>
> Then I think you haven't really contemplated how long the odds are.
> I would be astonished, since if you do the math, you find that such
> a situation is nearly impossible.
A good analogy here might be that one might walk into a room of 20
people, and, against the odds, find somebody else as old as you. But
the odds of them also being born on the same day as you are much, much
smaller.
By extension, the odds of finding a civilization with only a 1 million
year head start on us might not be terribly long. But the odds of
finding one with only a thousand year head start on us are vanishingly
small. And I daresay a technology even a millennia more advanced than
ours would probably have the run of the galaxy.
Regards,
Mike Combs