How strong is Aerogel? Could it be used instead of carbon fiber, or metal?

Answer 1

You should look up the wikipedia article on aerogel (I already have). It is great and has tonnes of info. But if you want the gist of aerogels, I can tell you that it is resistant to very high temperatures. I doubt it will ever replace carbon fiber or metals because as the guy before me stated, it is very brittle due to its jelly-like structure (it is actually mostly composed of air). It is also the least dense solid known to man I believe.

Answer 2

Aerogel is very strong but it also happens to be very brittle too. It might support a great load but if you hit it with an hammer you will get a pile of dust.