Scientists have discovered water on the moon's surface that originates from deep inside it.

The discovery is a major breakthrough in research being done on lunar water. The water — known as magmatic water — was detected using data from NASA's Moon Minerology Mapper (M3). Magmatic water is usually released to the atmosphere during a volcanic eruption.

"For many years researchers believed that the rocks from the moon were bone dry and that any water detected in the Apollo samples had to be contamination from Earth," said Rachel Klima, a planetary geologist who's a member of the NASA Lunar Science Institute's scientific and exploration potential of the lunar poles team.

"The interior of the moon is not as dry as we previously thought."

Data used was taken from the minerology mapper when the M3 was aboard the Indian Space Research Organization’s Chandrayaan-1 spacecraft in 2009. During that mission, the M3 fully imaged the crater Bullialdus on the moon.

"The exposure of these rocks [at the central peak of the crater] …enabled us to quantify the amount of internal water in these rocks," said Klima, whose findings are published in Nature Geoscience.

The internal magmatic water provides crucial information about volcanic processes on the moon and its internal composition.

"Understanding the internal composition helps us address questions about how the moon formed and how magmatic processes changed as it cooled."

In the end, more information about the moon's water will help expand understanding of where else it might exist on Earth's closest celestial neighbour. As well, finding sources of water on the moon means people could live on it without having to get water shipped from Earth.