I wonder if life forms on other planets might use different bases in its DNA. Or if it had DNA at all. Silicon polymerizes nicely and could form the basis for self-replicating molecules, perhaps.
I think Carl Sagan invented the term 'carbon chauvinism' in regard to this topic. Silicon does seem to be a viable alternative, doesn't it; but I consider the following:
(1) there's about 7 times more carbon than silicon in the universe *** .
(2) numerous carbon compounds have been found in space. While there's curently no evidence to indicate that such compounds in space lead to biogenesis, it does seem that those compounds form wherever it's possible, given enough time.
(3) carbon can form bonds with a greater range of elements than silicon can, giving rise to a greater number and complexity of compounds.
My guess is that on an any suitable planet with the requisite elements, it's much more likely that carbon, rather than silicon, will be the key player.
Still, as they say, 'Life' is full of surprises.
***
http://periodictable.com/Properties/A/UniverseAbundance.html_____
I hope they are sterilizing everything so we don't go seeding Earth life on these worlds before we can learn anything about them.
This refers to Mars missions:
http://mars.jpl.nasa.gov/msl/mission/technology/insituexploration/planetaryprotection/_____
I wonder where they are going to get the fuel for a hot air balloon in an atmosphere of methane? What if the atmosphere is combustible, and by lighting a hot air balloon we cause the whole atmosphere to go up in smoke? I'm sure someone has that angle covered, but it seems like a stumbling block nonetheless.
Is Titan's atmosphere really that combustible? After all, it appears to have survived meteor showers and impacts. Maybe the nitrogen content is too high. However that may be, it looks like they have it figured:
"On Mars, Montgolfieres [balloons] would be heated by the sun...On Titan, Montgolfieres would be heated from a radioisotope power source (RPS)".
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38.360/1/05-1506.pdf
Fascinating to speculate on the forms life might take on other worlds.
It sure is, especially in this age, when the search for extraterrestrial life is intensifying.
