What will happen when a SpaceX rocket collides with the Moon?

The piece in question is the upper stage of the rocket, and is about the size of a five-storey building, with a weight on Earth of at least 4,000kg (8,800 lbs).Astronomer Bill Gray, who first discovered the trajectory, says the object will land near the Einstein Crater, which is on the part of the Moon that receives daylight and is visible from Earth. He predicts it will create a crater more than 17m (56ft) in diameter.Getty Images/NasaThe Moon's surface bears witness to countless other impacts over a period of millions of yearsThe impending collision - predicted to happen at about 02:35 EDT (06:35 GMT) on Wednesday - is expected to captivate astronomers, both amateur and professional."It's something really huge smashing into the Moon. It's not remotely dangerous, we can just watch the show," says Dr Matt Bothwell, public astronomer at the University of Cambridge."It's going to impact and its going to send up a huge plume of dust, maybe 50km into the air or more, and that's going to spread sideways over time," Bothwell said.Given the Moon's lack of atmosphere and far weaker gravitational pull, the moment of impact will be "more impressive than any [similar] explosion on Earth", Bothwell said. Nothing will slow the object down, like the atmosphere would do here on Earth - and nothing will prevent the estimated million kilograms in debris from rocketing up into space.