life (cosmology)

[Preston]

Just dropping by, . So you all know I have not been lurking. I have checked out the site a few times, though not much.


I have been thinking about (and did a small amount of research) the thread in which we talked about cosmology and other life.

To be clear I have read there may be anywhere from 200 billion solar systems to 500 billion solar systems in the Milky Way galaxy – and that is our galaxy alone. There are supposedly around 80 billion galaxies in the observable universe. Some much larger than the Milky Way and others much smaller – yet still unfathomable for the average human mind to comprehend.

Whether there are 200 billion or 500 billion – both are numbers which can be all too easily said but far greater to comprehend – that means (as Peter said) there would be trillions of planets, if not 10's of trillions of planets in only our galaxy. If a planet was within a reasonable distance from a sun, then it could harness natural life. If a planet can harness natural life, then it most likely (not always, I think) would have conscious beings and even more sentient beings.

One key thing to understand is that the life-sustaining planet surrounding a solar system does not have to be in exact relation to our sun and our earth. There is life that can grow and nourish, easily, in what we call extreme environments.

So one point is, to my mind it is not a question of are there other sentient beings in our galaxy and beyond, it would seem to be an impossibility that there are not many? And by many, I would say around 10 billion, if not less if not more.

[Chris]

The universe is quite vast. But that is only one half of the equation. It is balanced out by the extreme unlikeliness of life forming.

There is something called the Drake equation which is used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. The equation is:

N = R* fp ne fℓ fi fc L

where:
N = the number of civilizations in our galaxy with which communication might be possible;
and
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space.

Of course, since many of these are not known quantities, this number is nothing but a guess. And that's what all of it is - a complete guess. We cannot compute the exact probability of life forming (we don't even know HOW it happened here in the first place), and we cannot compute the exact number of chances it has to form, so we cannot compute the chances that there is any other life out there. But even if it turns out to be very likely that there is other life out there, certain physical laws and other factors make it highly unlikely that we would ever know about it. So unfortunately there is not going to be an answer to this question any time soon, if ever.

[Preston]

Given the unimaginable size of the Milky Way galaxy, it is hard for me to imagine there is not other life in the galaxy. It just does not seem practical that there would not be, and a lot of it. I agree that it is a rarer thing for life to grow and form, though when one is talking in such large numbers rare isn't exactly 10, it isn't exactly 1 million, rare is probably more like 1 billion.

Either way, scientists are saying that a telescope called ATLAST will be able to tell whether there are planets that have life. Pretty interesting actually. The telescope will not be finished for around 15 years. Though, here is a link - http://en.wikipedia.org/wiki/Advance...pace_Telescope .

All The Best,
Preston

[Chris]

It's not just the vastness of the universe, though, it's the unlikeliness of life to form. We'd need to know the ratio of those two numbers to determine how likely it is, and we don't even know what the numbers are. If the unlikeliness of life forming is the greater number by a few orders of magnitude, it would be unlikely indeed that there is any other life.

If I had to guess, I'd bet there isn't any other life out there, at least not that we'll ever find. But as it so often happens with science, the search will bring us new discoveries and inventions that we didn't expect.

[Roehre]

IMO it is much more disturbing that though the chances that life is out there are infinitisemally small, given the trillions times trillions of potential "blue planets" out there, no other signs of life, let alone intellectually developed life, have been discovered or received.

Life might be in abundance out there, but there is also the possibillity that a law of nature exists, that life destroys itself (or at least intelligent life does), as might happen with this planet's life in the nearer of further future, given the power to do so by this human race.

[Michael]

Just to lower the tone of this fascinating discussion, in the words of Monty Python, let us "hope that there's intelligent life out there in space because there's bugger all down here on earth."

I notice that most of the above postings are from across the water. I don't know if you can get the BBC online, but there is a new series starting tomorrow (Sunday) night at around 9pm (GMT). It's a follow-up to a highly-acclaimed series on the solar system (which surprised everyone by pulling in a huge viewing audience).

Some info about it here:

http://www.guardian.co.uk/theobserve...stem-interview

Don't be put off by the presenter's pop-star image. He really does seem to know his stuff.

[Peter]

Just to lower the tone of this fascinating discussion, in the words of Monty Python, let us "hope that there's intelligent life out there in space because there's bugger all down here on earth."

I notice that most of the above postings are from across the water. I don't know if you can get the BBC online, but there is a new series starting tomorrow (Sunday) night at around 9pm (GMT). It's a follow-up to a highly-acclaimed series on the solar system (which surprised everyone by pulling in a huge viewing audience).

Some info about it here:

http://www.guardian.co.uk/theobserve...stem-interview

Don't be put off by the presenter's pop-star image. He really does seem to know his stuff.

Bring back Patrick Moore! Actually of course he's still going with the longest running tv series ever - 'The Sky at Night'.

[Peter]

It's not just the vastness of the universe, though, it's the unlikeliness of life to form. We'd need to know the ratio of those two numbers to determine how likely it is, and we don't even know what the numbers are. If the unlikeliness of life forming is the greater number by a few orders of magnitude, it would be unlikely indeed that there is any other life.

If I had to guess, I'd bet there isn't any other life out there, at least not that we'll ever find. But as it so often happens with science, the search will bring us new discoveries and inventions that we didn't expect.

It would be no more remarkable that life exists elsewhere than it is that it exists here. If it can exist here then there is at least the possibility that it does elsewhere - as to us ever finding it, I'm more skeptical, but then 100 years ago people would have said the same about walking on the moon.

[Michael]

Bring back Patrick Moore! Actually of course he's still going with the longest running tv series ever - 'The Sky at Night'.

He was on last night, shortly after the Brian Cox programme - to celebrate the 700th episode of "The Sky at Night". (Brian Cox himself was on this episode.)
I remember reading Patrick Moore's books on astronomy for young people when I was .... well, a young person. He is an amazing man - and also a composer!

[Quijote]

Dear Earthlings,
With regard to this thread, we wish to inform you that we have been following your species for some time now ...

[Preston]

Dear Earthlings,
With regard to this thread, we wish to inform you that we have been following your species for some time now ...

Philip - I always thought there was something rather odd about you, . Now I understand.

All The Best,
Preston

P.S. - Will Earth be destroyed when the galactic alignment occurs around Dec. 21, 2012? I am curious to know.

[Megan]

Philip - I always thought there was something rather odd about you, . Now I understand.

All The Best,
Preston

P.S. - Will Earth be destroyed when the galactic alignment occurs around Dec. 21, 2012? I am curious to know.

Actually, I rather think that Philip is an earthbound mortal, and not given to fanciful notions. Nothing odd about Pips.

[Preston]

Actually, I rather think that Philip is an earthbound mortal, and not given to fanciful notions. Nothing odd about Pips.

Well Megan, it was meant to be something of a slapstick joke based on Philip's joke. Not the borderline truth.

[Preston]

It would be no more remarkable that life exists elsewhere than it is that it exists here. If it can exist here then there is at least the possibility that it does elsewhere - as to us ever finding it, I'm more skeptical, but then 100 years ago people would have said the same about walking on the moon.

Yes, I agree. I too am skeptical about being able to travel to another planet. One of the closest solar systems, if I remember correctly, is around 4 light years away - which means traveling at the speed of light for 4 years. I do not know if such technology can be created based on the elements of Earth. Though that is not the real point either, the point is you would have to travel far beyond light speed (really a speed where there is no limit to how fast one could go - in a sense) to make a somewhat "quick journey" to another planet.

Asides from all that, personally, when I think about it, even if we did have the ability to travel at some kind of hyper-speed I imagine it would not be best for human beings to go to other species planets. We are destroying our entire planet so why destroy another?

[Joy]

I, too, have heard of the Drake equation and there's a lot of guess-timates out there.

Tonight on NOVA, a PBS program, their program is entitled 'Hunting the Edge of Space' mainly about how the telescope evolved and how it changed our understanding of our place in the universe. Another episode follows entitled 'The Milky Way'. Should be good.