New satellite data has found numerous volcanic deposits across the moon, adding to the growing body of evidence that there's a surprising amount of water beneath its barren-looking surface.

The ancient deposits are believed to consist of glass beads of water formed during explosive eruptions of magma.

The new research was published in the journal Nature Geoscience by scientists from Brown University.

For years scientists assumed the moon contained little in the way of water or other volatile compounds. That view started to change in 2008 when a research team found trace amounts of water in volcanic glass beads brought back to Earth from the Apollo 15 and 17 missions to the moon.

Then in 2011, further study of elements within those volcanic beads found that they contained similar amounts of water to some of Earth's volcanic rocks.

"The key question is whether those Apollo samples represent the bulk conditions of the lunar interior or instead represent unusual or perhaps anomalous water-rich regions within an otherwise dry mantle," said Ralph Milliken, lead author of the new research and an associate professor in Brown's Department of Earth, Environmental and Planetary Sciences in a written statement.

To detect water below the moon's surface from the significant distance of a satellite's orbit, the scientists measured the light that bounces off the moon. By looking at which wavelengths of light are absorbed or reflected by the surface, scientists can get an idea of the minerals and compounds beneath.

"The distribution of these water-rich deposits is the key thing," Milliken said. "They're spread across the surface, which tells us that the water found in the Apollo samples isn't a one-off."

The presence of water on the moon raises questions about how the moon came to be. Scientists have long believed that the moon is composed of debris leftover when an object as big as Mars collided with the Earth early in the history of our solar system. The moon was assumed to be dry because it seemed unlikely that the hydrogen needed to form water would have survived the heat of that impact.

Plus, a source of water there could be game-changing for future trips to the moon.

"Anything that helps save future lunar explorers from having to bring lots of water from home is a big step forward, and our results suggest a new alternative."