There are extremophiles which are resistant to radiation as well; Deinococcus Radiodurans, which can survive life in the cooling system of a nuclear reactor;

they have specially hardened protein coats around their DNA to prevent shuffling during radiation damage.

But they too are carbon based life.

One day the anti-radiation strategy of these extremophiles will become part of the genetic armory of humanity also, thanks to inheritable genetic modification.

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Orion's Arm . The Starlark . Voices: Future Tense- Novella Contest Issue! . OA Flickr set

Silly notion, but here it is anyhow. In the very early universe, before the "waste products" C, O, and N were excreted by supernovae, might life not have evolved in some other way? We make much of the fact that Carbon is the only suitable chemical basis, but there was a long era, after the creation of Population III stars, when no chemistry at all was possible, there being no chemicals. Helium forms no compounds, hydrogen only one, the diatomic molecule. The stars themselves were different-- with no metals to drive the carbon cycle and other catalytic cycles, they had to be more massive to burn at all, using the proton-proton reaction. The planets also would have evolved differently, with no dust to stick to, it's tricky getting gas to form planets at all! Still, I wonder if, on the smallest possible such planet superconductive He might not have self-organized and developed information storage and processing. The contradiction, of course, is that the heat of formation of the planet would forbid being cool enough to superconduct. Within the larger planets, tho, pressure and temperatures prevail that force H to behave like a metal. A very lonely metal. Very small amounts of Li and even smaller amounts of Be and B to party with, but they would have been segregated toward the core by their weight. Being the only active chemicals, theirs would be the only chemistry. (Borane, borane!) The dwarf stars of that era are still around, as the universe is not old enough for them to have evolved outside their stable range, and while their planets might not be capable of the preferred chemistry, they have had a very long time in which to do something. My point (see, I did remember) is that we know very little about the chemistry of light elements at extreme high pressure, and still less about the phase behavior. For example, there are now at least twelve allotropes of water ice (different crystal forms arising at different temp/press combinations). I'm not pressing any particular point of view here, just striking a blow against Carbon Chauvinism. (Isn't it funny how, when the only tool in your box is a hammer, everything gets compared to a nail?) Oh, yeah-- the same set of arguments apply to our local, more evolved gas planets J-S-U-N-P-.... Regards, Steve

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Ignoramus et ignorabamus.-- Reymond

Wir mussen wissen. Wir werden wissen.--Hilbert

Pick one.

I know I'm a little late jumpin in here, but I think Carl Sagan covered this very nicely in "Cosmos". Yes silicone based life might be possible as well as other elements (maybe elements we have yet to discover), but carbon is plentiful in the universe and seems to be the most likely element to be used for life (err...so to speak). It's been a while since I saw that episode of Cosmos or read the book, but he covers it pretty well. On the other hand, I'm also rather biased...I really like the late Dr. Sagan's work :-) He had a unique way of putting a lot of this into perspective for those of us that aren't quite as scientifically inclined. He also would have been very proud of the work we're doing with the Mar's Rovers and with Cassini...shame he missed it.

What we may eventually find is that there is other kinds of life out there, such as silicone-based, but it might be -very- rare...it might exist, but not nearly as commonly as carbon-based.

I would like to add that just because a life form is carbon based, does not mean that it's going to look anything like us or anything we have on this planet. Life that evolves on other worlds (sentiant or not) will be adapted to that world and even on another "Earth-like" world, intelligent life could evolve much different from what we know. The diversity of life on our planet alone is astounding and if you multiply that by the possibility of other evolutions on other planets...perhaps even "billions and billions", carbon-based or not, the outcome could be truly mind-blowing!

Just my $.02
Bright Blessings All,
Jim

Here, here! I cannot agree strongly enough. My personal pet peeve is to hear someone call something a "theory" without so much as a single attempt at theoretical discovery or basis on anything known to science. I dont know enough about chemistry to add to the specifics of this particular debate, but I do think the "anything is possible" approach to these kinds of discussions comes up all too often and only serves to diminish their real value.

Well said, indeed! Thank you. B)

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<span style='color:blue'><span style='font-size:12pt;line-height:100%'><span style='font-family:Impact'>--==:: A. W. ::==--</span></span></span>

Surely if there was 'a theoretical discovery' (I am presuming you mean proof) it would cease to be a theory and become fact.

And the suggestion that silicon based life may be possible is based on science (chemistry/physics) which I only loosely understand also. But still, scientific basis nonetheless.

As for 'anything is possible' responses... I'd rather be a dreamer and an optimist than an empiricist. B)

I know lots of people like tidy answers, but sometimes I think the messy ones can be more fun (that's probably why I'm a creative and not a scientist!) :P Don't rain on my parade man!

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<span style='color:purple'>My voices don't like you!</span>