Ever since man first landed on the Moon scientists have been looking for signs of life there, and now they've found an important one - water.
It's taken about a year and three space missions, but three spacecraft have found signs of a fine film of water coating particles in the lunar dirt.
There's not a lot, but experts say the water could help astronauts who want to try to live on the Moon in the future.
They're also excited as they think the soil could be used as rocket fuel.
Now for the science bit - scientists say dirt particles on the surface of the Moon contain oxygen.
Scientists are still testing the Moon soil samples to check their water theories
Solar winds from the sun contain hydrogen, which mixes with the oxygen in the dirt to make water.
It's thought you could squeeze one litre of water out of one cubic metre of Moon soil.
But don't expect to see people living on the Moon any time soon.
Scientists are still trying to make sure that the samples of lunar soil didn't get water in them when they were brought back down to Earth to be tested.