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yks 6nnetu hing
08-21-2009, 08:05 AM
wait for it....

wait for it...





there's life on Earth! Scientifically proven! and detected from space!

http://blogs.discovermagazine.com/badastronomy/2009/08/04/lcross-detects-life-on-earth/

Zanguini
08-21-2009, 08:25 AM
Hmmm what if aliens dont breathe oxygen?
All of my aliens breathe methane.

Gilshalos Sedai
08-21-2009, 08:39 AM
Yeah... calibrating the instruments to look for oxygen consumption ... probably not the best way to look for life. I imagine a methane breathing species would scan our planet and conclude there was no life here, either.

GonzoTheGreat
08-21-2009, 09:19 AM
On the other hand, now we know that we can actually detect some life. That's better than before, when we only knew that we might fail to detect life if it was there. Of course, we still have the latter, as Zan points out, so we really haven't lost anything as a result of this. That's government money well spent, I would say.
Be honest: how often do you gain something from a government program without losing something else at the same time?

Crispin's Crispian
08-21-2009, 09:54 AM
I don't think there is just one way to search for life. Searching for free oxygen is certainly not a bad way to look for life, even if it's incomplete.

Why would we assume methane is going to be more common?

Gilshalos Sedai
08-21-2009, 10:03 AM
It was just an example.

Hopper
08-21-2009, 10:41 AM
wait for it....

wait for it...





there's life on Earth! Scientifically proven! and detected from space!

http://blogs.discovermagazine.com/badastronomy/2009/08/04/lcross-detects-life-on-earth/Yes, but the important question is whether there's intelligent life on Earth.

Gilshalos Sedai
08-21-2009, 10:50 AM
"The surest sign of intelligent life in the Universe is that none of it has tried to contact us yet." --Bill Watterston, Calvin & Hobbes.

GonzoTheGreat
08-21-2009, 10:58 AM
I don't think there is just one way to search for life. Searching for free oxygen is certainly not a bad way to look for life, even if it's incomplete.

Why would we assume methane is going to be more common?Well, there is quite a lot of the stuff on other planets. All the gas giants have quite a bit of methane on them.

Mars too has some methane in the atmosphere. There it is not known whether that is the result of geological processes or of underground life.

All in all, the detection of methane tells you that you've detected methane. Only in very special cases (Earth, possibly Mars) may it provide additional information.

Oxygen, on the other hand, is such a reactive gas that there is no known non-life-related mechanism which can produce significant quantities of it in a planetary atmosphere. It would simply react with something in a short while, and thus disappear.
For instance: if photosynthesis stopped on Earth, then in a couple of million years the oxygen concentration of the atmosphere would sink below one percent. On a lifetime of billions of years, that's rather quick.
Thus, if you do detect oxygen on a planet, then the only known explanation is that there is life.

Crispin's Crispian
08-21-2009, 11:20 AM
Well, there is quite a lot of the stuff on other planets. All the gas giants have quite a bit of methane on them.

Mars too has some methane in the atmosphere. There it is not known whether that is the result of geological processes or of underground life.

All in all, the detection of methane tells you that you've detected methane. Only in very special cases (Earth, possibly Mars) may it provide additional information.

Oxygen, on the other hand, is such a reactive gas that there is no known non-life-related mechanism which can produce significant quantities of it in a planetary atmosphere. It would simply react with something in a short while, and thus disappear.
For instance: if photosynthesis stopped on Earth, then in a couple of million years the oxygen concentration of the atmosphere would sink below one percent. On a lifetime of billions of years, that's rather quick.
Thus, if you do detect oxygen on a planet, then the only known explanation is that there is life.Sorry--that's not what I meant. I meant why would we assume methane breathers would be more common? The specific chemistry involved with oxygen and respiration seems pretty, well, specific.

GonzoTheGreat
08-21-2009, 11:53 AM
Planets with methane in their atmospheres seem a lot more common, and they are generally rather big too. Together, that means a lot of opportunity for methane breathers to live happily.
Of course, whether or not such life is actually possible is another thing, but that's a problem for biologists, not something astronomers need worry about. Apart from the astro-biologists, but that's their own fault.