Berlin AP
What is the difference between a meteor and a meteorite? Meteors are pieces of space rock, usually from larger comets or asteroids, that enter the Earth's atmosphere. Many are burned up by the friction and heat, but those that survive and strike the Earth are called meteorites. They often hit the ground at speeds of up to 30,000 kph, releasing a huge amount of energy, according to the European Space Agency (ESA).
How common are meteor strikes? Experts say that smaller strikes happen five to 10 times a year. Large meteors such as Friday's in Russia are rarer, but still occur roughly every five years. Most of them fall over uninhabited areas where they do not injure humans.