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by zdragnar 830 days ago
Silicon has only superficial similarities to carbon. Even at high temperatures, water and oxygen prevent silicon from substituting for carbon in any of what we are familiar with as organic molecules.

Your linked paper points out that the only viable solvent that supports a large variety of silicon chemistry is sulphuric acid, and even then it would need to be very poor in oxygen since silicon-oxygen bonds are so strong it ends up being much more strongly preferred over si-si bonds.

It makes for an interesting conversation, but I can't imagine spending an entire class going over what amounts to a massive distraction from the lesson plan.

All that's left is going to amount to an effectively dismissive answer, I suppose (though I agree that teachers who are intentionally dismissive are doing it wrong).

1 comments

Wouldn’t an environment that has a significant sulfuric acid content naturally also a relatively limited free oxygen?

I’m thinking of Venus. That sort of environment would satisfy all criteria and would also start to get into the temperature ranges that would make Si-Si bonds possible.

That would at-least bracket the types of planets and their history to a useful extent.

Sulphuric acid actually has a lot of oxygen and hydrogen in it, and the presence of any metal or even high enough temperature will cause it to break up.

In a lab, it makes for a good solvent, but any place that has sulphuric acid will have both water and oxygen.

Venus, notably, has little to none of both. What free oxygen that does exist is from CO2 and CO breaking down in the atmosphere from the intense and extended venusian day. Most of the sulphur on Venus is sulphur dioxide (a tiny percentage of the atmosphere), and water vapor is a measly 20ppm.

Even if all of that water was sulphuric acid (which it may well be), there's simply not enough of it staying still long enough to form the repeating patterns of chemistry that might reasonably be called life.