One day,experts agree, a large rock from space (an asteroid) will hit the earth it might happen tomorrow.Or it might not happen for another 5,000 years.It's difficult to say.We do know,though, that one of these space rocks -Asteroid1950DA- will travel very close to our plannet on 16 march 2880. Scientists first discovered the asteroid in 1950. Two weeks later,they lost it.When they found it again in 1999,it was moving closer.Destination:Earth.