Life on other planets

[Kablamo]

what do you think about this?

i would have to say a definite yes, while on holiday i was reading a book which had heaps of pictures of every part of the universe. and it is huge, we live in a galaxy on one planet, which is surrounded by millions of other galaxies and if we are the only people in the universe, which has millions upon millions of planets in unknown galaxies, well, that seems far fetched now.

[PALEMOON]

well, assuming the universe is indeed infinite, that it would contain at least some form of life. how can it not?

[Kablizzy]

110%. There's even life in our solar system.

Now whether that life is intelligent, that's a bit more rare, but I'm sure there's intelligent fauna in our galaxy.

[MattKestrel]

How can we define whether life is intelligent or not? If it wasn't, it would be too simple to understand our definition; if it was, it would probably possess higher intellect than us if they manage to reach us first, and thus defy our substandard definitions.

[Kablamo]

well by intelligence, wouldnt it mean that they can think for themselves? becuase if there were other life and they could not think, but they reached us. thats not intelligence, its communism

[Izzy]

Well, it did happen on a certain pale blue dot, why shouldn't it happen elsewhere.

Which reminds me, I was abducted 3 days and 27 minutes ago.

[Kablamo]

Which reminds me, I was abducted 3 days and 27 minutes ago.

... ok

[TribulatioN]

There's no reason for it not to be possible.
The possibilities are endless. Another planet out there could have dinosaurs, whereas another one could even have humans more advanced than us.

[t̷s͢uk̕a͡t͜ư]

You'd also have to take time into consideration. We humans have only really been "civilized" for the last several thousand years, which is just a blink relative to how long the universe has been around. Even if by some crazy random happenstance there aren't any other forms of life in the universe in our same multi-millennial window, there damned well have been and will be.
Of course, in all practicality, no forms of life will ever actually encounter another in their civilized periods, either.

...and now I'm thinking how frickin' weird it is, given the tremendous amount of time humans spent effectively being about as evolved as we are now but before we were civilized, and working with the expectation that humans will last at least another good few thousand years, that I'm alive and about in this time. If you're working in ranges on the order of millions, you'd expect chance to deposit you in the order of the millions (there are 10 times as many numbers in the millions as there are in the hundreds of thousands, which themselves have 10 times the numbers of the tens of thousands, etc.), not near the maximum point of the range, give or take a few thousand.
I don't know whether to be thankful that I'm not hunting mammoth or to feel gypped because I'm alive before we've spread to other solar systems. :|

[Rose]

I definitely believe that there is life on other planets, but I don't believe there is intelligent life anywhere else but Earth. Think about it: Earth is perfectly placed to allow us to live like we do. I remember reading that if Earth was just a few thousand miles closer to the sun, we would burn up; likewise, if it was a few thousand miles farther away, we would freeze. Also, you have to take into account that it depends on the star, too. What are the chances that there's another planet perfectly placed in a solar system with a perfectly-sized star that also has never been destroyed by a meteor, supernova, etc.? I just don't believe intelligent life could survive from its most basic state anywhere but Earth.

[LittleViking]

I definitely believe that there is life on other planets, but I don't believe there is intelligent life anywhere else but Earth. Think about it: Earth is perfectly placed to allow us to live like we do. I remember reading that if Earth was just a few thousand miles closer to the sun, we would burn up; likewise, if it was a few thousand miles farther away, we would freeze. Also, you have to take into account that it depends on the star, too. What are the chances that there's another planet perfectly placed in a solar system with a perfectly-sized star that also has never been destroyed by a meteor, supernova, etc.? I just don't believe intelligent life could survive from its most basic state anywhere but Earth.

First, remember that the Earth is 93 million miles from the Sun, and its distance from the Sun varies 3 million miles every year just by of the shape of its orbit. In fact, science puts the range at which a planet's conditions could be like Earth (the habitable zone) at about 40 million miles. Now, I guess this is a relatively small window - Pluto orbits at 3.7 billion miles after all - but it's still large enough that every hundred planets probably has a few habitable zone planets around it.

Regarding our star, the Sun is actually a pretty common brand occurrance. The Sun is on the small end of the solar size scale, and smaller stars are more than abundant in our galaxy. Almost 90% of stars around us are the size of the Sun or smaller. Really, stars smaller than the Sun may be even more friendly to life because of their longer lifespans, and those stars are much more common than our own. While almost any star should be able support life as long as the planet is at the right distance, huge stars tend to die off in a matter of millions of years - not nearly enough time for life to take hold - and these small ones last billions or tens of billions.

As for meteors, well, life on Earth may have been destroyed by meteors. Several times, in fact. It's possible that early life was formed and destroyed a few times before our earliest ancestors came to be. Devastating collisions like that are something that happens constantly in the early stages of a star system's life. The Solar System likely had planets and meteors bouncing around all the time for the first billion years of its existence (as is evidenced by the surface of the Moon), but after that, collisions die down to almost nothing.



What I'm interested in at the moment is subsurface life elsewhere. Energy from a star can't be counted on when you get more than a certain distance out, but volcanic heat from the planet's core is a always a good source of energy. Volcanic heat on Earth has been known to support life below the surface. Deep sea volcanic vents, for example, too deep in the water to allow any light through, are covered in bacterial life that feeds off of the energy of the vent. There are even types of bacteria that live inside of deep subsurface rocks, powered by the heat and water at that depth. The reason this excites me is that these conditions are much more common than conditions like the surface of the Earth. Our Solar System only has one place that matches the Earth's surface, but it might have a dozen that match Earth's subsurface environment. Now, I understand this isn't intelligent life, but at this point, finding life at all outside of Earth would radically change the way people approach space science, and our place in the universe.

[capt_weasle]

I desperately wish to be alive by the time we discover something similar to what Kablizzy described, or at least other hospitable planets, regardless of whether or not intelligent live resides on them.

[LittleViking]

...at least other hospitable planets...

http://www.space.com/scienceastronomy/0 ... lanet.html

[Rikaninja]

I believe it too be true. As kablamo and some others said, there has to be something out there other than us.

[jean-luc]

If you look at it from a mathematical perspective... Given a certain period of time, there's a finite number of possible outcomes (an unfathomably immense number, but still a finite one). given that space is of infinite size... there are an infinite number of intelligent life forms.

[capt_weasle]

...at least other hospitable planets...

http://www.space.com/scienceastronomy/0 ... lanet.html

Yeah, I've read about that, but there seems to still be a lot of discussion about it's range to the sun it orbits. I suppose that should count, but I'm too picky to notice. I guess I won't be happy until we've landed something on it, and we don't get pictures of lots of rocks ;)

EDIT: Also, I had some thunks. What if at this point in time we still live in an young universe, and it just so happens we are the first intelligent life to have existed. That would mean we have to get out of here, get out to other planets. Another idea would be that we're the third planet to harbor life in our own solar system. I mean if the sun is constantly growing (slowly, but surely), that would mean the "hospitable zone" would also be slowly expanding. What if Mercury once had life similar to ours, but slowly died out because of the increasing size of the sun, until the hospitable zone reached Venus, in which the whole process started all over. That would mean we would be next. What if the possible "fossils" of bacteria found on Mars wasn't ancient life, but new life trying to get a head start, but the conditions just aren't quite enough? In a few million (billion?) years when the sun is big enough, the new hospitable zone would envelope Mars, thus being more primed for life. The frozen water in the ice caps would melt, possibly digging up some of that deep under-ground life Kablizzy had mentioned. Viola! New life. By this theory that would mean we wouldn't have much time (relatively) on Gliese 581 C, because it orbits so close to the tiny star. Could that planet one day be what Mercury is to us today?

Just some ideas, probably a little stretched, but it's fun to think!

[T3chno]

100% sure about it. I just hope they discover it in our lifetimes though, being as awesome as it could be.

[Eiturlyf]

If the universe is so immensely huge, there has to be life somewhere.

[lord_day]

Where did this idea that the universe is infinite come from?

[Darkandroid]

Good point.
Could the Big Bang really create an infinite amount of matter?
Because all matter is conserved, so there might not be as much universe as we think...

[t̷s͢uk̕a͡t͜ư]

Where did this idea that the universe is infinite come from?

It sorta makes sense to me how you could assume it. I mean, sure, matter and energy are obviously not infinite, because a finite amount of energy was sent from the big bang in all directions, so the matter and energy in the universe is expanding at most at the speed of light.
But it has to be expanding into some kind of space that's already there, and that total void is what I think of when I hear people talking about an infinite universe. It's this region of absolute nothingness, I think, that people talk about, where any form of information whatsoever hasn't traveled. And I guess if you were to be floating out there and have that wave of expanding universe hit you, you'd see the big bang in all its glory.

[otters]

Where did this idea that the universe is infinite come from?

It sorta makes sense to me how you could assume it. I mean, sure, matter and energy are obviously not infinite, because a finite amount of energy was sent from the big bang in all directions, so the matter and energy in the universe is expanding at most at the speed of light.
But it has to be expanding into some kind of space that's already there, and that total void is what I think of when I hear people talking about an infinite universe. It's this region of absolute nothingness, I think, that people talk about, where any form of information whatsoever hasn't traveled. And I guess if you were to be floating out there and have that wave of expanding universe hit you, you'd see the big bang in all its glory.

In that case, what's with the "if the universe is infinite there MUST be life somewhere" argument? It should be true only if there's an infinite amount of inhabitable planets.

[Condog]

Where did this idea that the universe is infinite come from?

It sorta makes sense to me how you could assume it. I mean, sure, matter and energy are obviously not infinite, because a finite amount of energy was sent from the big bang in all directions, so the matter and energy in the universe is expanding at most at the speed of light.
But it has to be expanding into some kind of space that's already there, and that total void is what I think of when I hear people talking about an infinite universe. It's this region of absolute nothingness, I think, that people talk about, where any form of information whatsoever hasn't traveled. And I guess if you were to be floating out there and have that wave of expanding universe hit you, you'd see the big bang in all its glory.

In that case, what's with the "if the universe is infinite there MUST be life somewhere" argument? It should be true only if there's an infinite amount of inhabitable planets.

If there are an infinite amount of space, then there would be an infinite amount of worlds. However, not all of these are inhabitable. So, there must logically be other worlds capable of supporting life.

[t̷s͢uk̕a͡t͜ư]

Where did this idea that the universe is infinite come from?

It sorta makes sense to me how you could assume it. I mean, sure, matter and energy are obviously not infinite, because a finite amount of energy was sent from the big bang in all directions, so the matter and energy in the universe is expanding at most at the speed of light.
But it has to be expanding into some kind of space that's already there, and that total void is what I think of when I hear people talking about an infinite universe. It's this region of absolute nothingness, I think, that people talk about, where any form of information whatsoever hasn't traveled. And I guess if you were to be floating out there and have that wave of expanding universe hit you, you'd see the big bang in all its glory.

In that case, what's with the "if the universe is infinite there MUST be life somewhere" argument? It should be true only if there's an infinite amount of inhabitable planets.

No one is saying that the number of planets is infinite (at the very least, I'm not). The argument relies on the fact that there is a stupidly large number of planets.
Let's say that any bunny has a 0.01% chance of being a vampire. In a room full of 20 bunnies, obviously you're not going to expect that any of them are vampires. But if you're talking about 48.3 quadrillion bunnies, it'd be silly to think that none of them are vampires, even though the number of bunnies is far from infinite.

[UnknownKirbyMan]

I do not think that there is intelligent life elsewhere in the universe.

Or that the Big Bang happened.