University of Tennessee, Knoxville, researchers have studied the existence of water on the moon and discovered its origins. 

Larry Taylor, study leader and a professor in the Department of Earth and Planetary Sciences at the University of Tennessee, Knoxville, along with a team of researchers, have found where the water on the moon originated.  

Taylor was not only able to trace the lunar water's origins, but he was the one who discovered that the moon even had water in the first place. This lunar water discovery he made last year changed all beliefs that the moon was completely dry.

Since this discovery, researchers also found that the moon has an abundance of water. So much, in fact, that humans could possibly live on the moon. Now, Taylor has found the origins of all this lunar water.  

Taylor and his team believe the water came from comets crashing into the moon shortly after it formed. They came to this conclusion after studying rocks that were retrieved from the Apollo mission. The team then measured the rocks' water signatures through the use of secondary ion mass spectrometry, which could allow researchers to tell where and when the lunar water originated.  

As it turns out, water on the moon is different from water on Earth. This discovery led to the belief that comets supplied the moon with a majority of its water back when it originally formed.  

It is believed that the moon formed when the nascent Earth and Theia collided, sending materials out into space. These materials created the moon, and according to Taylor's theory, comets were hitting both the moon and Earth. But because the Earth already had an abundance of water, it was not affected by these comet collisions and did not acquire enough of the comets water for it to be integrated into its original water system. But the moon, which was dry at this point, received a majority of its water via comet collisions.  

"This discovery forces us to go back to square one on the whole formation of the Earth and moon," said Taylor. "Before our research, we thought the Earth and moon had the same volatiles after the Giant Impact, just at greatly different quantities. Our work brings to light another component in the formation that we had not anticipated - comets." 

Taylor's new theory of how the moon formed suggests that water has been present throughout the moon's entire history. While comets supplied the moon's internal supply of water, solar winds supplied the moon's external supply of water.  

What makes the water on the moon different from water on Earth is that it contains the ingredients for water - hydrogen and oxygen - but is not yet water. If the rocks on the moon were heated up, the ingredients would turn into water.  

"This water could allow the moon to be a gas station in the sky," said Taylor. "Spaceships use up to 85 percent of their fuel getting away from Earth's gravity. This means the moon can act as a stepping stone to other planets. Missions can fuel up at the moon, with liquid hydrogen and liquid oxygen from the water, as they head into deeper space to other places such as Mars." 

This study was published in Nature Geoscience.