There's even more water on the moon than we previously thought, according to new analysis of tiny glass beads left over from ancient volcanic eruptions.

The naturally occurring beads were collected in the 1970s as part of the Apollo 15 and 17 missions, which landed near zones of volcanic activity. The beads formed when magma bursting onto the surface crystallized in such a way that water became trapped inside.

However, scientists couldn’t be sure if the Apollo samples are unique or if other volcanic flows on the moon are filled with water-bearing glass. (Find out how flying oceans of magma help demystify the moon's creation.)

In a new study published today in Nature Geoscience, scientists reexamined the Apollo samples and used