Curiosity discovers organic matter on Mars!

[FishInferno]

Basically my point is that we cannot expect any alien life to be the same as Earth life

[Bill Phil]

But there are basics and other laws that ANY life must adhere to.

[FishInferno]

But there are basics and other laws that ANY life must adhere to.

how can we determine this based on only ONE known life-bearing planet?

[Bill Phil]

how can we determine this based on only ONE known life-bearing planet?

Energy levels that allow a solvent, such as water, to be in liquid form is a requirement.

That and certain chemicals are very common and are thus likely to show up on multiple life-bearing worlds.

[Frida Space]

Ammonia. It could allow for colder climates. But it's not as good as water...

the temperature range at which ammonia is liquid is probably too low for life.

[Bill Phil]

Antarctica has been much colder...

[Frida Space]

Antarctica has been much colder...

Can you provide a source? Antarctica was once covered by trees and land, so the temperature presumably wasn't colder than today.

Icy bodies in the outer solar system usually have a surface temperature of around 100K, if not less. I can't believe temperatures in Antarctica were ever lower than that, as you state.

[78stonewobble]

Haven't they also found ... simple ... organic molecules in nebula and / or newly forming starsystems?

Comet life might be impossible, but I wouldn't completely rule it out.

[Bill Phil]

Antarctica was covered by land a very long time ago. Recently it's been very cold, although life still requires a medium it proves the life can life in very cold temperatures. This is very general information. You can look up Abtarctica's climate yourself and find many sources.

[Frida Space]

However, we don't know if life at current temperatures in Antarctica would have been able to form in the first place. If the temperatures have dropped over a long period of time, than life forms can adapt to them. And still, temperatures in Antarctica have never even come close to what Europa Triton & Co. experience everyday, so this argument really make no sense.

[Kryten]

Antarctica was covered by land a very long time ago. Recently it's been very cold, although life still requires a medium it proves the life can life in very cold temperatures. This is very general information. You can look up Abtarctica's climate yourself and find many sources.

What life? What creatures are supposed to be living in central Antarctica?

[FishInferno]

What life? What creatures are supposed to be living in central Antarctica?

I'm not sure, but it wasn't always really cold before continental drift happened.

[Newt]

I think it is important to note that really extremely little is understood about exactly what conditions life needs to first form, and then survive. While there is much reason to believe that terrestrial life arose from subocean hydrothermal vents, we do not know this to be the case, and we even less know this to be the only possible source. We have much evidence to suggest that life is extremely versatile in where it elects to live, given time to adapt (there certainly are life forms that could hibernate on comets, and given a little adaption perhaps they could awake, eat, and reproduce every perihelion, only to freeze solid again for a few decades), but again, if we do not know the conditions in which life can form, it is very difficult to predict where it will be, even if we know it can live in an area.

It is to answer these questions, among other things, that we are exploring this star system. There is strong evidence that life formed in it at least once, but an ambiguous answer to whether it formed at other times. We are unsure of exactly the conditions under which it may have formed that once. There are logical deductions which we may make about life's needs and abilities, it is evident that it needs an energy source, for instance, though the parameters for that energy source are unclear. But nothing beats evidence. Currently we are in the stage where we need several working hypotheses, and a determination to test our ideas. That is one of the reasons that we have rovers on Mars, and why we have a (dead) lander on Titan, to pursue evidence to tear our hypotheses to shreds, and, eventually, to not. Currently we see only a sliver of a very large picture, and are only sketching out what the rest might look like.