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What Silicon-Based Life Might Be Like
Nancy_A writes "While the world as we know it runs on carbon, science fiction's long flirtation with silicon-based life has spawned a familiar catchphrase: 'It's life, but not as we know it.' Although non-carbon based life is a very long shot, this Q&A with one of the U.S.'s top astrochemists — Max Bernstein, the Research Lead of the Science Mission Directorate at NASA headquarters in Washington,D.C. — discusses what silicon life might be like."
There's more ways to form a complex compound than just Si-Si-Si-Si... chains (which, as you note, tend to oxidize into crystaline silicon dioxide). As a random example as proof, look at silica gel. Si-O-Si-O-Si-O... etc. Chain it pretty much as long as you want, functionalize the side chains, etc.
When it comes to LNAWKI (Life Not As We Know It), I think a lot of people lack creativity to a tremendous degree -- envisioning the situation as altering only one parameter (say, substituting silicon for carbon but otherwise keeping the chemical structures roughly the same).
"You see, Government is a system that is based on weapons." -- Timster
OK, I would concede the general point that it somewhat depends on how one defines "life", but I would still argue that the grandparent posts are largely correct:
As noted above, the fact remains that Si - Si bonding is much weaker than C - C bonding due to the relative positions of these elements in the periodic table, which means that any kinds of polymerized molecular species that you might want to try to kick off life with still probably wouldn't last as long in a primordial environment as their carbon-based counterparts. They're more susceptible to being broken up into shorter-chained fragments by UV radiation, cosmic rays, etc.
Things like repeated Si-O chains simply require more factors to be favorable: both elements in the same place, physical conditions that favor sufficiently large quantities of specific silicon oxidation over any other process, etc. Not saying it's impossible, but it just seems significantly less likely to be the dominant chemistry than comparatively strong organic polymerization processes, particularly given the cosmic elemental abundance distributions (i.e. where you get silicon & oxygen in sufficient quantities, you probably get enough carbon as well).
What's funny about attempts to visualize other types of life forms is, we tend to visualize those life forms in our own environmental terms. That is, we tend to assume some basic atmospheric conditions, pressure ranges, and temperature ranges. We "assume" certain basic conditions that resemble our own conditions.
Silicone? How about we break the cycle by trying to visualize silicone under hundreds of thousands of tons of pressure, and thousands of degrees, with and atmosphere of ammonia? Or, alternatively, in a vacuum at tens of thousands of degrees? Partial pressure atmospheres at near 0 degrees kelvin?
Of course, the question arises then, how and why are mankind interacting with such creatures under such conditions?
Of course, I was enamored with the idea of "living rock" as I child. Some story I read mentioned it, and I had the idea that some rock was really alive. Of course, it isn't - or IS IT?!?!? Nothing says that we are smart enough to recognize alien life when we see it. Geologic time and man's time are so different, that we might not even recognize that a rock actually breathes, or moves, or reproduces. Again, let's step outside our own familiar conditions. Assuming that time might be entirely different for some other life form in conditions that are inimical to us, why would we hang around long enough to collect the data necessary to determine that this or that rock really is alive?
I certainly don't have any answers about the existence of life outside our own experience. But, it amuses me to see the almost idiotic assumptions that people make when considering and debating the possibility. “It’s life, but not as we know it” How about the possibility that a face to face meeting with another life form might be fatal to one or both of the participants in the meeting? His environment is a poisonous atmosphere (to me) and my own body radiating heat might be fatal to him!
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
How about we break the cycle by trying to visualize silicone under hundreds of thousands of tons of pressure, and thousands of degrees, with and atmosphere of ammonia? Or, alternatively, in a vacuum at tens of thousands of degrees? Partial pressure atmospheres at near 0 degrees kelvin?
Max Bernstein mentions something very similar to that in TFA.
Dorminey â" DO YOU THINK THAT SILICON-BASED LIFE MIGHT EXIST SOMEWHERE OUT THERE?
Bernstein â" Maybe deep below the surface of a planet in some very hot hydrogen-rich, Oxygen-poor environment, you would have this complex silane chemistry. There, maybe silanes would form reversible silicon bonds with selenium or tellurium.
How about the possibility that a face to face meeting with another life form might be fatal to one or both of the participants in the meeting? His environment is a poisonous atmosphere (to me) and my own body radiating heat might be fatal to him!
A biochemist's vision of such an encounter, for your listening pleasure.
Mit der Dummheit kämpfen Götter selbst vergebens