What Silicon-Based Life Might Be Like 92
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."
Re:Why not here? (Score:5, Insightful)
vlm answered the musical question:
Why not evolve Si life here?
Thusly:>/p>
Carbon 300 ppm second to pretty much everything but vanadium and stuff like that. For all intents and purposes the earth is not the idea place for a carbon based life form.
Incorrect, I'm afraid.
If you exclusively look at the abundance of carbon in the Earth's makeup, you miss the most crucial aspect of hydrocarbon-based biochemistry: the abundance of water as a solvent for hydrocarbons, particularly here on the surface of the planet, where the incredible profusion of possible compound-producing reactions benefits tremendously from sunlight as a source of energy input to trigger the making and breaking of hydrocarbon bonds.
A world where carbon is greatly more abundant - but water is largely absent - wouldn't necessarily be more conducive to the evolution of life.
The reason why we're made out of relatively rare C instead of tremendously available Si is C chemistry is incredibly better than Si chemistry for bio, or heck, chemistry in general. The fine article didn't give it enough justice or maybe the editors edited out the chemistry rants. Lets just say that Xe biochem is not all that more unlikely or difficult than Si biochem would be (in other words, nearly totally freaking almost incomprehendibly impossible vs just merely incredibly extremely impossibly unlikely)
This, on the other hand, is a much better point ... and, IMnsHO, one deserving of an "Insightful" upmod.
Stupid rocks (Score:5, Insightful)
There should have been a question like "is there an environment that might make it more plausible for Silicon life"? What about planets that are molten or have oceans, lakes, and rivers of acid. Why would an intelligent rock walk around in place where they will become immobile? Sounds like something only dumb rocks would do.
Hmm (Score:2, Insightful)
Interesting. Though I am curious why Silicon life hasn't already evolved on the Earth.
Think about it. There isn't necessarily a reason why Silicon / Carbon / other-based lifeforms can't all evolve in the same environment. There's no law, save those of Physics / Chemistry / etc., that says that if you have one, you cannot have the other.
So, why is earth filled with only Carbon-based lifeforms (to our knowledge)? Perhaps there is something poisonous about our planet, with regards to Silicon lifeforms, such that they might evolve on other, more hospitable planets.
Re:Easy (Score:5, Insightful)
They used to say nothing could survive in the vacuum of space, the bottom of the ocean, in geysers, highly acidic conditions and so many other places. If they knew about the oceanic geothermal vents (like the black smokers) back then, they'd have sworn they would be lifeless.
Now of course, we have the entire category of Extremophiles that live in those very places and conditions.
Additionally, we have lifeforms that have copper based blood instead of iron, ones that respire sulfur instead oxygen, and diatoms build their skeletons/shells/cell walls out of silica. And now they may have found one that exchanges its phospates for deadly arsenic and lives.
All in all, there are significant portions of life on this world that was considered science fiction several decades ago. Does that mean it's possible that life in other parts of the universe can be very different than ours? Sort of. It means that our understanding of what is necessary for life is incomplete due to our exposure to only our own type of biology. There may be very strange biochemistry out there, but most of it that we might recognize as life will probably be similar to ours. (That's the biochemistry, not the form, or if intelligent, culture.)