Moon Has 100 Times More Water

Moon Has 100 Times More Water, New Study Suggests

A moon rock brought to Earth by Apollo 11, humans' first landing on the moon in July 1969, is shown as it floats aboard the International Space Station.

Part of Earth can be seen through the window. The 3.6 billion year-old lunar sample was flown to the station in honor of the July 2009 40th anniversary of the historic first moon landing.

It will be returned on shuttle mission STS-128 to be publicly displayed. Credit: NASA

The moon's interior may harbor 100 times more water than previous estimates, according to a new study that took a fresh look at samples of moon rocks collected by Apollo astronauts nearly 40 years ago.

The researchers determined that the lunar water likely originated early in the moon's formation history, suggesting that it is, in fact, native to the moon.

Scientists at the Carnegie Institution's Geophysical Laboratory, and other colleagues, said it's likely that the water was preserved from the hot magma that was present when the moon began to form – some 4.5 billion years ago.

They also think that the water, which is locked up in lunar rocks and material, is likely more widespread in the moon's interior than previous studies estimated. These findings now suggest that the lower limit for total water on the moon could be 100 times greater.

"When the rocks were first returned from the Apollo missions, it was pretty obvious that they were really dry," Francis McCubbin, lead author of the study, told SPACE.com. "A lot of people attributed the dry nature to something fundamental about how the moon formed. I think an estimate was thrown out there of less than 1 part per billion (ppb) water, because the presumption was that there was almost no water on the moon."

Tracking moon water

In 2008, research of volcanic glass beads brought attention to the fact that there might be more water in the moon's interior than scientists had previously thought. At the time, McCubbin and his colleagues were searching for water in lunar minerals, but at that point they had only models and calculations that suggested higher water content.

Since then, observations from unmanned probes from NASA and other space agencies have confirmed the presence of water in lunar material and water ice on the moon's surface.

For this new study, the researchers were able to compare their calculations to analyses of samples of Apollo moon rocks and a lunar meteorite from Africa.

"We combined the measurements with models that characterize how the material crystallized as the moon cooled," McCubbin said. "We found that the minimum water content ranged from 64 parts per billion to 5 parts per million – at least two orders of magnitude greater than previous results."