Silicon-Based Life?
One favorite of science fiction writers is life based on the chemistry of
silicon rather than carbon, because silicon is probably the element most
similar in chemical properties to carbon. However, even though silicon is
the most similar, it is not very similar; carbon chemistry is still much richer than
that of silicon. And we have the observation that even though
silicon is more than a hundred times more abundant than carbon, we know of no
silicon-based life forms walking around on our planet.