Is Astrobiology a Legitimate Scientific Field?

[LURCH]

Comets and asteroids in the protoplanetary nebula would have been efficiently heated by Aluminium-26 decay.

But that heating should only last a few million years at most, as I understand.

 

[qraal]

But that heating should only last a few million years at most, as I understand.

According to Wickramasinghe's thermal modelling the comets of sufficient size efficiently retain heat from the initial decay spike to remain liquid for far longer. Don't forget the Sun's energy input would have been significant too. Once the comets were scattered into the Opik-Oort Cloud they would've preserved any biomolecules created, perhaps even concentrating them sufficiently for Life to begin. Biogenesis gurus Leslie Orgel & Stanley Miller independently concluded that proto-life biochemistry would have been accelerated by freezing the medium, due to the concentrating action of the way water freezes especially when full of solutes.

 

[qraal]

Here’s a very good treatment of why our favorite molecules are the ones that won the “biology lottery” and some insight into the wanta be’s:
http://books.nap.edu/catalog.php?record_id=11919#toc

A very good reference and FREE!

 

[planethunter]

Given the shear unimaginable size of the universe, the question is not whether there is intelligent life outside of earth, but instead how much life?

Look into Drake's equation for an interesting discussion of this assertion.

Given the biology of some of the known exoplanets, life similar to life on Earth is not probable. However, we are bound to find an Earth size planet in its sun's habitable zone that will give us the best change of life elsewhere in the universe.

 

[Chronos]

Agreed. Once you establish that planets are common [which has been done], the existence of extrasolar life is a certainty. Are any such life forms intelligent [as in human like intelligence] - that is unknown at present. My guess is there must be at least a half dozen human-like civilizations scattered across the galaxy at present. The real problem is traversing the vast distances of space between stars, imo. I doubt any civilization has yet mastered that feat. The energy costs are just too enormous. Perhaps a civilization a million years ahead of our own could accomplish this feat. I suspect they are too busy exploring their own neighborhoods for resources and potential relocation sites to give much thought to traveling here.

 

[LURCH]

But drake's equation is nothing but a string of complete unknowns. It does not give us any idea about the likelyhood of extrasolar life, nor do I believe Drake intended it to. It merely gives us a formalism by which that likelyhood could be calculated at some point in the future, when some of the variables can be filled in.

As for intelligent life; look into Fermi's Paradox.

 

[cosmolojosh]

Somebody found amino acid on a comet

 

[planethunter]

Somebody found amino acid on a comet

I am aware of NASA supposedly finding some kind of organic material on a martian meteorite some time ago, which according to them ended up being because it had been contaminated.

Where did you hear the story about the amino acid on a comet?

 

[cosmolojosh]

Planethunter, go to science.discoery.com. It is the website of the science channel. Go to brink. Then go to videos and watch proof of alien life.

 

[Chronos]

Find ozone in an exoplanet atmosphere and you have found the smoking gun for life. That study is already underway.

 

[cosmolojosh]

There is 2 problems with seti anyway. 1. it would take a human like species. There is also a million and 1 other explamaations for what seti is looking for.

 

[JerryClower]

Does astrobiology imply that life exists elsewhere in the Universe besides earth?

 

[qraal]

Does astrobiology imply that life exists elsewhere in the Universe besides earth?

That's what it means, though of course it might all be related to Life here by panspermia.