Venus vs Titan: which is more likely to support life?

[Diche Bach]

On 9/27/2016 at 8:55 AM, Matuchkin said:

Here's a nice source.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1664683/

There are some nice planetary and lunar analogies in this article, and good explanations of conditions at the time that life began on Earth.

Great article, just needs a 'theme song' . .  .

 

ADDIT: sounds like some of you folks know your biochem pretty well: way better than me.

So I'm curious to hear you speculate: how the heck does an organic like glycine wind up on a comet!?

Edited September 30, 2016 by Diche Bach
question about glycine

[todofwar]

30 minutes ago, Diche Bach said:

Great article, just needs a 'theme song' . .  .

 

ADDIT: sounds like some of you folks know your biochem pretty well: way better than me.

So I'm curious to hear you speculate: how the heck does an organic like glycine wind up on a comet!?

It's a radiation induced process I believe. Glycine is O-C-C-N, essentially. You link carbon monoxide and cyanide, slap on a hydroxyl radical to make HO2CCN, and reduce your CN to make glycine iirc. I haven't read up on it in a while

[Diche Bach]

Interesting. So basically: got some Oxygen? got Carbon? got Nitrogen? (of course you've got Hydrogen, how could you NOT have Hydrogen!?) are these elements mixed in the soil/ice matrix in proportions that are within a certain threshold? Add "light" -> est voila! amino acids! ?

Is that pretty much what we are talking about?

What about nucleic acids?

I was aware that proteins are far more complicated, as you mentioned above, and pretty much cannot form outside fairly narrow environmental ranges. But what about peptide strands?

I guess "life" along the lines of a virus or prion might not be that surprising, but based on what you and others have said here, the mere presence of amino acids on a comet is not that suggestive of prokaryotic (much less eukaryotic) life for simple reason: proteins are a huge step "up" in complexity from amino acids and/or nucleic acids?

Edited September 30, 2016 by Diche Bach

[todofwar]

43 minutes ago, Diche Bach said:

Interesting. So basically: got some Oxygen? got Carbon? got Nitrogen? (of course you've got Hydrogen, how could you NOT have Hydrogen!?) are these elements mixed in the soil/ice matrix in proportions that are within a certain threshold? Add "light" -> est voila! amino acids! ?

Is that pretty much what we are talking about?

What about nucleic acids?

I was aware that proteins are far more complicated, as you mentioned above, and pretty much cannot form outside fairly narrow environmental ranges. But what about peptide strands?

I guess "life" along the lines of a virus or prion might not be that surprising, but based on what you and others have said here, the mere presence of amino acids on a comet is not that suggestive of prokaryotic (much less eukaryotic) life for simple reason: proteins are a huge step "up" in complexity from amino acids and/or nucleic acids?

Well, in a sense yes. Nucleic acids are much harder, don't know if those will need something like a geothermal vent to get going. And of course it's a matter of timescale. That glycine build up happened over billions of years. 

You can get peptide strands, they'll just be very rigid. As for life, it will be much more complex than that. Probably the thing that amazes and fascinates me more than any other is the transition from prebiotic to biochemistry. The machinery involved is so complex now it's hard to think back to how it might have worked.