Not alone in the visible universe, not even in our own galaxy

The probability that we are, I think, is lower than 1/200 billion.

With 200 billion galaxies, each with over 100 billion stars, there are
roughly 20,000 billion billion stars in the visible universe.
That is 20,000 - 000,000,000 - 000,000,000 stars.

Assume each galaxy has only one planet with intelligent life
on it (at our level of civilization or better; this is a very very
very
conservative estimate) then there are 200, 000,000,000
civilizations in the visible universe.

How many of these would be 1 million or 10 million or 100 million
years ahead of us, assuming the universe is approximately 15 billion
years old and 100 million years is only 0.66% of this timespan?
100 million years is only 0.66% of the total timespan.

It is easy to contemplate that there can be many thousands of these
civilizations anywhere from 1 to 100 million years ahead of us,
civilizations that survived, colonized other galaxies and/or are
travelling for millions of years,

Assuming some are in galaxies 1 billion light years away from
our own Milky Way, then if they travelled e.g. in cryogenic
state for over 500 million years at the speed of light, they still
would not have reached us. This assumes that speed of light is
the upper limit.

In a nutshell, the numbers are so large, even if you multiply a very
low probability factor times a huge number you will get a sizable
number. And I think that probability factor is not that
small, but much higher than one planet per galaxy of 100
billion stars. It is likely there are as many or more planets
than stars in each galaxy.

But if there is an 'advanced' Mr Galactic Darth Bushius
living closeby e.g. at the other side of our own galaxy, a galaxy with
a
diameter of over 100,000 light years, it would still take him 100,000
years to get here. Thank 'God' for the vast distances and the
billions
and billions and billions of stars, even in our own galaxy.

On Jun 7, 9:32 pm, "Carl Sagan's billions" wrote:

Assume each galaxy has only one planet with intelligent life
on it (at our level of civilization or better; this is a very very
very
conservative estimate) then there are 200, 000,000,000
civilizations in the visible universe.

Nonsense. You have no way of knowing if this is conservative or not.

Intelligent life may be extremely common, being possible over a large
range of temperatures and prevailing chemistries. But it's also
possible that it's almost impossible, requiring a precise chemistry,
range of temperatures, and even evolutionary direction.

For example, it might be all but impossible to develop intelligence
without color vision to make object boundaries pronounced. Color
vision might only provide evolutionary benefit with particular
combinations of plant life around.

Simply put, we have no idea how common or rare intelligent life is. It
may be that you could create a billion universes and never see it. It
could be that it's all over the place in almost every conceivable
universe.

But you are just pulling figures out of your ass.

DS

Last time that great scribe Carl Sagan's billions
chipped away at his/her stone these gems of wisdom for posterity ...

The probability that we are, I think, is lower than 1/200 billion.

With 200 billion galaxies, each with over 100 billion stars, there are
roughly 20,000 billion billion stars in the visible universe.
That is 20,000 - 000,000,000 - 000,000,000 stars.

Assume each galaxy has only one planet with intelligent life
on it (at our level of civilization or better; this is a very very
very
conservative estimate) then there are 200, 000,000,000
civilizations in the visible universe.

How many of these would be 1 million or 10 million or 100 million
years ahead of us, assuming the universe is approximately 15 billion
years old and 100 million years is only 0.66% of this timespan?
100 million years is only 0.66% of the total timespan.

It is easy to contemplate that there can be many thousands of these
civilizations anywhere from 1 to 100 million years ahead of us,
civilizations that survived, colonized other galaxies and/or are
travelling for millions of years,

Assuming some are in galaxies 1 billion light years away from
our own Milky Way, then if they travelled e.g. in cryogenic
state for over 500 million years at the speed of light, they still
would not have reached us. This assumes that speed of light is
the upper limit.

In a nutshell, the numbers are so large, even if you multiply a very
low probability factor times a huge number you will get a sizable
number. And I think that probability factor is not that
small, but much higher than one planet per galaxy of 100
billion stars. It is likely there are as many or more planets
than stars in each galaxy.

But if there is an 'advanced' Mr Galactic Darth Bushius
living closeby e.g. at the other side of our own galaxy, a galaxy with
a
diameter of over 100,000 light years, it would still take him 100,000
years to get here. Thank 'God' for the vast distances and the
billions
and billions and billions of stars, even in our own galaxy.

I think probably most civilisations don't last a million years. Perhaps
they come and go like flowers in the spring. Constantly.

The probability is worked out with the Drake equation. The values of the
variables is guess work because we simply do not have data to go on.

--

Remove both YOUR_SHOES before replying
apatriot #1, atheist #1417,
Chief EAC prophet
Jason Gastrich is praying for me on 8 January 2009

Apatriotism Yahoo Group
http://groups.yahoo.com/group/apatriotism

"Those who can make you believe absurdities can make
you commit atrocities." - Voltaire

On Jun 8, 1:34 am, David Schwartz wrote:
On Jun 7, 9:32 pm, "Carl Sagan's billions" wrote:

Assume each galaxy has only one planet with intelligent life
on it (at our level of civilization or better; this is a very very
very
conservative estimate) then there are 200, 000,000,000
civilizations in the visible universe.

Nonsense. You have no way of knowing if this is conservative or not.

Intelligent life may be extremely common, being possible over a large
range of temperatures and prevailing chemistries. But it's also
possible that it's almost impossible, requiring a precise chemistry,
range of temperatures, and even evolutionary direction.

For example, it might be all but impossible to develop intelligence
without color vision to make object boundaries pronounced. Color
vision might only provide evolutionary benefit with particular
combinations of plant life around.

Simply put, we have no idea how common or rare intelligent life is. It
may be that you could create a billion universes and never see it. It
could be that it's all over the place in almost every conceivable
universe.

But you are just pulling figures out of your ass.

DS

Agreed. Actually Sagan and Drake and other expositors of science
also pulled fugures out of their asses and purveyed them in popular
books. Not that there is anything wrong with speculating, but when a
scientist writes for laymen he should clearly indicate when he is
speculating wildly and when he is giving accurate numbers that can be
taken seriously. The honest answer to the question is the one given
by Arthur C. Clarke. Once when asked how common he thought
intelligent life would be in the universe he replied: "The best
scientific estimate at this point is somewhere between exactly once in
the universe and every other star." That about sums up the state of
our knowledge.

On Thu, 07 Jun 2007 21:32:27 -0700, Carl Sagan's billions wrote:

The probability that we are, I think, is lower than 1/200 billion.

With 200 billion galaxies, each with over 100 billion stars, there are
roughly 20,000 billion billion stars in the visible universe.
That is 20,000 - 000,000,000 - 000,000,000 stars.

Assume each galaxy has only one planet with intelligent life
on it (at our level of civilization or better; this is a very very
very
conservative estimate) then there are 200, 000,000,000
civilizations in the visible universe.

How many of these would be 1 million or 10 million or 100 million
years ahead of us, assuming the universe is approximately 15 billion
years old and 100 million years is only 0.66% of this timespan?
100 million years is only 0.66% of the total timespan.

It is easy to contemplate that there can be many thousands of these
civilizations anywhere from 1 to 100 million years ahead of us,
civilizations that survived, colonized other galaxies and/or are
travelling for millions of years,

Assuming some are in galaxies 1 billion light years away from
our own Milky Way, then if they travelled e.g. in cryogenic
state for over 500 million years at the speed of light, they still
would not have reached us. This assumes that speed of light is
the upper limit.

In a nutshell, the numbers are so large, even if you multiply a very
low probability factor times a huge number you will get a sizable
number. And I think that probability factor is not that
small, but much higher than one planet per galaxy of 100
billion stars. It is likely there are as many or more planets
than stars in each galaxy.

But if there is an 'advanced' Mr Galactic Darth Bushius
living closeby e.g. at the other side of our own galaxy, a galaxy with
a
diameter of over 100,000 light years, it would still take him 100,000
years to get here. Thank 'God' for the vast distances and the
billions
and billions and billions of stars, even in our own galaxy.

A more immediate problem than that of reaching us from several hundred
thousand light years away is that of *finding* us. We are a tiny needle
in a gigantic haystack. We have only been radiating artificially produced
electromagnetic waves for a few hundred years, so there is only a handful
of star systems close by that would have heard our noise.

--
MarkA
(pretend this is a clever sig line)

On Thu, 07 Jun 2007 21:32:27 -0700, "Carl Sagan's billions"
wrote:
- Refer: . com
The probability that we are, I think, is lower than 1/200 billion.

Be honest, and admit this is not a "probability" at all,
but a "guess".

--

Yes, indeed, we can only make some educated guesses
as to if there is intelligent life on other planets, or moons,
or other locations for that matter.

My guess is that it's possible, therefore it should be
of continuing exploration and examination.

I would remind people, when Gliese 581C was found
to be in a habitable zone just 22ly from earth, the odds
of habitable planets went way up past the educated
guess of the notable Drake equation.

I would also make a reminder of the fact that many of
brown dawrf suns can't even be seen just yet, and that
because of their long life duration, may also be inhabitable.

It wasn't that long ago, perhaps within your own lifetime,
that the idea of other planets orbiting suns was just
as impossible by many peoples teachings.

Poll numbers suggest that most Americans believe
that there is indeed other intelligent life out there...
and I'd just suggest, that they're probably right.

On Fri, 08 Jun 2007 19:58:18 -0700, studio wrote:
- Refer: .com
Yes, indeed, we can only make some educated guesses
as to if there is intelligent life on other planets, or moons,
or other locations for that matter.

My guess is that it's possible, therefore it should be
of continuing exploration and examination.

I would remind people, when Gliese 581C was found
to be in a habitable zone just 22ly from earth, the odds
of habitable planets went way up past the educated
guess of the notable Drake equation.

I would also make a reminder of the fact that many of
brown dawrf suns can't even be seen just yet, and that
because of their long life duration, may also be inhabitable.

It wasn't that long ago, perhaps within your own lifetime,
that the idea of other planets orbiting suns was just
as impossible by many peoples teachings.

Poll numbers suggest that most Americans believe
that there is indeed other intelligent life out there...
and I'd just suggest, that they're probably right.

Poll numbers *also* show that most "Americans" belive that the earth
was created AFTER the domestication of the dog, that Homeopathy
works(!), that Horoscopes are real, and that there is a genocidal
sky-pixie deserving of worship!

--

"The honest answer to the question is the one given
by Arthur C. Clarke. Once when asked how common he thought
intelligent life would be in the universe he replied: "The best
scientific estimate at this point is somewhere between exactly once in
the universe and every other star." That about sums up the state of
our knowledge."

I agree, but Carl Sagan understood the size of our galaxy and the
'bilions and bilions and billions and billions' of stars --- the
number is so huge that when you multiply a very low probability
times an 'astronomically' large number = what do you get?

It is speculation, 'guessing' of course, that is the point.
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars

If you repeat this line 100,000 times = 2000 pages of 50 lines,
you have not even reached the number of stars in one single
galaxy, our own Milky Way.

And there are an estimated 100 to 200 billion galaxies.
So you would need to multiply these 2000 pages, not by
10, not by a million, not by a billion, but by 100-200 billion.

Carl Sagan understood this magnitude.
Most people including most Americans are so poorly trained in
mathematics, they have 'no idea, no idea'
(to borrow Jodie Foster's words).

That's why I can contemplate and speculate and even contend:
It is very unlikely life on earth is unique in our galaxy.
It is even much more unlikely life on earth is unique in our universe.

On Jun 9, 11:14 am, "B.T.World" wrote:
"The honest answer to the question is the one given
by Arthur C. Clarke. Once when asked how common he thought
intelligent life would be in the universe he replied: "The best
scientific estimate at this point is somewhere between exactly once in
the universe and every other star." That about sums up the state of
our knowledge."

I agree, but Carl Sagan understood the size of our galaxy and the
'bilions and bilions and billions and billions' of stars --- the
number is so huge that when you multiply a very low probability
times an 'astronomically' large number = what do you get?

It is speculation, 'guessing' of course, that is the point.
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars
One million stars

If you repeat this line 100,000 times = 2000 pages of 50 lines,
you have not even reached the number of stars in one single
galaxy, our own Milky Way.

And there are an estimated 100 to 200 billion galaxies.
So you would need to multiply these 2000 pages, not by
10, not by a million, not by a billion, but by 100-200 billion.

Carl Sagan understood this magnitude.
Most people including most Americans are so poorly trained in
mathematics, they have 'no idea, no idea'
(to borrow Jodie Foster's words).

That's why I can contemplate and speculate and even contend:
It is very unlikely life on earth is unique in our galaxy.
It is even much more unlikely life on earth is unique in our universe.

I also contemplate and speculate thusly. However, I stop short of
contending. The evolutionary sequence that led from primordial slime
to you and me COULD be so astronomically improbable that it is unique
in the galaxy or even the universe. On the other hand, as Spock was
wont to say: "It's life Jim, but not as we know it". When we
consider the posibilities of radically different processes that could
also lead to intelligent life, then we are truly speculating in
ignorance. My guess (which is as worthless as anyone else's) is that
simple life should be reasonably common. Intelligent live, well, who
the hell knows.

Anyways I stand by my opinion that Sagan and other scientific
writers were irresponsible to purvey such numbers to laymen without
clearly indicating their speculative nature. I have met
mathematically and scientifically unsophisticated people who have
quoted Sagan's speculations as authoritative.