One of the most frequent questions I'm asked is "are they radioactive?" The good news is that meteorites are far less radioactive than your computer monitor screen, and are quite safe to handle.
Another popular myth is that meteorites always glow white hot all the way to the ground, producing a shower of sparks as they explode on impact, making a big crater. Well, it's true that meteors are travelling at fantastic speeds of around 20 miles per second when they first hit the upper atmosphere, but all of that energy is quickly converted to heat and light as the meteor meets air resistance and slows down, producing a short but very impressive fireball with loud explosions. Hitting the atmosphere at 20 miles per second has an effect similar to slamming into concrete– the meteor explodes into several pieces and slows down rapidly, until all of its energy is spent. The remaining pieces fall to the ground in complete darkness and silence, at no greater speed than if they had been dropped from an aeroplane.
The very rare exceptions to this rule are the truly massive meteors, but we're talking BIG here! An incoming meteor would have to be the size of a family garage for the atmosphere not to slow it down appreciably, and it would be travelling so fast that you probably wouldn't even see it coming.
Luckily for us, the vast majority of meteors are somewhat smaller! The 44 kilograms of assorted meteorites, which fell on the town of Barwell, Leicestershire on Christmas Eve 1965 were originally a single chunk of space rock no larger than the desk that you're probably sitting at while reading this. Barwell is a good example of a multiple fall of meteorites, where the incoming meteor exploded into many pieces as it hit the atmosphere – most incoming meteors explode, often producing a meteorite shower.
A one kilo chunk of the Barwell meteorite, which has spent the last 30 years in a museum collection.
Pieces found in Barwell today will be heavily stained a deep rusty-brown colour.
Many meteorites were scattered over Barwell, with stones ranging in size from that of a pea, up to the size of a small melon. I've heard reports that roof repairers still find fragments of the Barwell meteorite in rain guttering. Meteorite hunters know that when one meteorite has been found, there's probably tens, hundreds or maybe even thousands more in the same area, just lying there waiting to be picked up by a budding meteorite hunter.
Not all meteorites are large – most of them are smaller than an orange. I found several of these tiny meteorites in the Arizona desert; they fell to Earth in 1912, but the dry desert environment has been very kind to them.