BERLIN – A meteor exploded in the sky above Russia's Ural Mountains on Friday, causing a shockwave that blew out countless windows and injured hundreds of people with flying glass. Here's a look at those objects in the sky:

Q. What's the difference between a meteor and a meteorite?

A. Meteors are pieces of space rock, usually from larger comets or asteroids, which enter the Earth's atmosphere. Many are burned up by friction and the heat of the atmosphere, but those that survive and strike the Earth are called meteorites. They often hit the ground at tremendous speed — up to 30,000 kilometers an hour (18,650 mph) — releasing a huge amount of energy, according to the European Space Agency.