I've been dipping into Bill Bryson's A Short History of Nearly Everything - Special Illustrated Edition (Amazon link) and finding that time just zips by. I bought it ages ago, but didn't have very high expectations for it because I generally like to have complex ideas explained to me by experts in those fields, not by humorous travel writers, but BB has done a very capable job. I've spotted one or two facts that are very slightly awry, but by and large it's packed with tidbits that I'd love to commit to memory. I thought it might be fun to share a few, so I'll post one each day until I get bored with the idea.

Today's: There are three problems with blowing up any big rocks that might be on a collision course with Earth. 1) We probably wouldn't spot them until they started to heat up in our atmosphere, which would give us less than a second to mount a space mission. 2) Blowing them up probably wouldn't work. 3) When NASA reorganised its archives a little while back it threw away the plans for the Saturn 5 rocket which is the only device humans have ever invented that could send a team even as far as the moon.