Tim O'Brien, associate director of the University of Manchester's Jodrell Bank Observatory, has described the metoer which exploded in southern Russia on Friday as a "completely abnormal experience".
It made a sonic boom in the atmosphere, and that hit buildings and shattered windows. That is what seems to have caused the injuries.
It's a completely abnormal experience. This thing appeared in the distance, raced over the horizon and was followed up 30 seconds or a minute later by a huge boom as the shockwave hit the ground. I can imagine that would be very frightening.
Where did it come from? What was it made of? What can be done if we know a meteor or asteroid is going to hit Earth?
A look at some of the best video from the Russian Meteor. More than 400 people were injured after it flew over a Russian city.