Nasa has given its fullest explanation yet of exactly what it was that exploded over Russia two weeks ago.
The meteorite, which impacted Chelyabinsk, close to the Ural Mountains, injured more than 1,000 people.
Since the impact huge amounts of frenzied research have told us exactly where it came from, how fast it was going and why it struck where it did.
Now Nasa has released a handy video to go over the finer points of what it was made from, why it hit and how likely it is that it will happen again (tip: very).
Take a look, above.