Is silicon-based life a legit possibility?
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>>7790908
Not really, silicon ionizes too easily to maintain large covalent systems.
Organic (carbon) chemistry is extremely diverse. Silicon is tetravalent like carbon but doesn't produce such rich chemistry, as far as we know. This limits the complexity of any life-form expected to emerge from silicon chemistry. It might also limit the means by which chemical automata could form under moderate conditions, or abiogenesis.
The Milky Way is about 4600 ppm carbon and 650 ppm silicon, so carbon also wins in abundance. I suppose it's unlikely that the silicon fraction would often be concentrated either.
Probably possible, but unlikely and limited.
Silicon isn't anywhere near as compound-forming like Carbon is. It's been noted that over 90% of the compounds you commonly run across as a living organism, contain Carbon. Carbon's versatility in forming compounds makes it a primary organic element. Combined with Hydrogen, Oxygen and Nitrogen, you end up with a CHON biosphere, probably in all instances where biospheres form.
>>7790908
Statistically, yes, but very briefly.
>>7791664
Elaborate?
>>7790908
Wouldn't a problem be that organisms as we know them now oxidize carbon to CO2 in cellular respiration, and CO2 is a gas at temperatures and pressures suitable for life which diffuses easily out of a cell, but silicon based life would produce SiO2 which is a crystal solid at temperatures and pressures suitable for life. How would the hypothetical silicon organism excrete this respiration product?