A satellite the size of a bus is expected to crash back on Earth later tonight.
Scientists aren't sure where it will land, but they think the chances of it hitting someone are seriously low.
Most of the satellite is expected to burn up when it passes through the atmosphere but some big chunks may fall to earth.
So much of the planet is covered with water that it's likely it may crash into the sea.
Space agency Nasa has warned that if you do find any bits of the satellite, don't touch it, call the emergency services.