Are Non-Carbon Based Life Forms Really Possible?

[Vanadium 50]

Saying that really restricts how your mind can think.

As it's supposed to. Science is about restricting the number of things you need to look at to only relevant models - and by relevant I mean "agrees with the data".

We know that the atomic and molecular spectra are the same from stars and gas clouds in other galaxies as they are here. That's very powerful evidence that they are the same as here.

 

[Arch2008]

Well, these are the folks actually looking for exobiology:
http://astrobiology.nasa.gov/documents-and-reports/
and this is what they are hoping to find:
http://books.nap.edu/catalog.php?record_id=11919#toc

NASA is considering all possibilities and the search is no longer Earth-centric/carbon only.

 

[harvellt]

I think it falls to the fact carbon is so much more reactive than silicon that in any environment that would support silicon life it would also support carbon life. Natural processes tend to the path of least resistance the chances of silicon based life are extremely low. As for filling a niche I think we are just beginning to see the extremes that carbon based life can survive. Look at Extremophiles, carbon based organisms that not only survive at temperatures grater than 100 C but flourish, or in a environment with a PH>3, or my favorite are radio resistant bacteria organisms capable of resisting nuclear radiation.