3 questions: Ben Weiss discusses what a wet moon might mean

Sep 30, 2009
The Moon. Credit: NASA

Last week, NASA and other agencies announced results from instruments aboard three different spacecraft which all indicate that there is water present in the surface soil, or regolith, of the moon. Although the amount is very small, it is much more than had been predicted.

MIT Associate Professor of Planetary Sciences Benjamin Weiss discusses the implications of the new finding.

Q: How surprising was the detection of water on the surface of the moon, especially in daylight regions?

A: It was enormously surprising and exciting. The accepted wisdom has been that the moon is and has always been bone dry. Although water was identified in the Apollo samples, it was generally discounted as terrestrial contamination. The three studies last week, which involved spectroscopic data from three different spacecraft taken over a period of 10 years, showed that not only does the lunar soil apparently have up to 0.1 percent by weight of water in its upper layer, but that this water is forming and "exhaling" on timescales of just a lunar day. This means that much of this water was recently emplaced and is present all over the surface of the moon. Until now, it has generally been assumed that if there is any water on the moon, it would almost exclusively be in the form of ice located mainly in permanently shadowed craters at the lunar poles.

Q: Does this finding suggest that there may be amounts of water in the lunar environment that would be sufficient to be a resource for future astronauts working on the moon?

A: The spectroscopic evidence for lunar water only reflects the top few millimeters of the lunar surface. Therefore, these data do not constrain the abundance of lunar water throughout most of the lunar soil. Nevertheless, if astronauts were to harvest soil containing water with an abundance like that inferred from the spectroscopic data, then they would have to process about a ton of regolith to obtain a liter of water. Given that water was observed to leave the soil every lunar day due to solar heating up to 100 degrees Celsius, this implies that simply heating the to these relatively mild temperatures would be enough to liberate the water for use. I think this makes it a promising resource for astronauts.

Q: Does this discovery tell us anything new about the formation or evolution of the moon, or raise new questions about it?

A: It is not yet clear what is the source of this water. If much of it is indigenous, it suggests that the moon may have been far wetter than we supposed. This may have important implications for one of the leading hypotheses for the origin of the moon — that is was formed from the debris of a giant meteoroid impact on the young Earth — which predicts that the source material which formed the moon should have been extensively heated. Alternatively, if the main source of the is the solar wind or comets, then it says little about the original composition of the .

Provided by Massachusetts Institute of Technology (news : web)

Explore further: NASA asteroid defense program falls short: audit

add to favorites email to friend print save as pdf

Related Stories

Water May Not Have Formed Mars' Recent Gullies

Mar 16, 2006

If you're a scientist studying the surface of Mars, few discoveries could be more exciting than seeing recent gullies apparently formed by running water. And that's what scientists believed they saw in Mars ...

Moon's South Pole: No Evidence For Ice Sheets

Oct 18, 2006

Using the highest resolution radar-signal images ever made of the moon – images from the National Science Foundation’s (NSF) Arecibo Telescope in Arecibo, P.R., and the NSF’s Robert C. Byrd Telescope ...

NASA eyes water in Moon mission

May 21, 2009

NASA on Thursday said it was on target for a June mission to scour the Moon's surface for landing sites and water that would allow humans to work and even live on Earth's nearest neighbor.

Recommended for you

Image: Crescent Mimas

45 minutes ago

A thin sliver of Mimas is illuminated, the long shadows showing off its many craters, indicators of the moon's violent history.

India's spacecraft 'on target' to reach Mars

23 hours ago

An Indian spacecraft is on course to reach Mars, an official said Monday, following a 666-million-kilometre voyage that could see New Delhi's low-cost space programme win Asia's race to the Red Planet.

Rosetta's lander Philae will target Site J

Sep 15, 2014

(Phys.org) —Rosetta's lander Philae will target Site J, an intriguing region on Comet 67P/Churyumov–Gerasimenko that offers unique scientific potential, with hints of activity nearby, and minimum risk ...

User comments : 0