NASA announced yesterday there are traces of water on the moon. But before you pack your bathing suit, it's probably still too soon to start planning for a lunar outpost and swimming pools on the moon.
[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/09/25/green.nasa.art.jpg caption="James Green of NASA says the moon is still very dry despite the discovery of traces of water."]
James Green is one of the NASA officials who made the announcement yesterday. He is the director of the Planetary Science Division at NASA headquarters. Green spoke to John Roberts on CNN’s “American Morning” Friday. Below is an edited transcript of the interview.
John Roberts: Any photos we've ever seen of the lunar surface show it to be an arid and dusty place, yet this research shows maybe that doesn't tell the whole story. What did you find?
James Green: John, that's right. However we didn't find the swimming pools or even mud puddles as you point out. The water that we found is trapped in the rocks. In fact, the observations from the Moon Mineralogy Mapper over the last six months as it maps the entire moon show that this water is everywhere on the moon. And, in fact, it's variable in terms of its content.
But even with that said, the amount of water – it's drier on the moon than it is in our driest deserts. But it is a start in terms of looking more about what's going on at the moon, its origin, its evolution and we still have another big step to move where we're going to look at water that might be trapped in the permanently shadowed craters. We don’t know much about that yet.
Roberts: Well, if this is either water or a precursor to water, where does it come from? We have seen in pictures of Mars that there might be evidence that water flowed along the surface at some point. Is there similar evidence in the moon? Or does this come from somewhere else?
Green: We believe that in the early history of the moon, as it coalesced after a large impact with the Earth creating the moon 4.5 billion years ago, that the water was mostly gone, and that's what makes these results so surprising. It tells us that the moon through a variety of processes is retaining some water. It could come from comets. We know quite well that comets do have large amounts of water. However, we also know – and this is probably not well known – that even asteroids have water. So the moon, for some odd reason, is able to retain water with respect to time. There might also be several other processes that do it that we just don't know about yet.
Roberts: What I find very fascinating is that the original lunar soil samples that were brought back from the Apollo missions to the Johnson Space Center in Houston – it was originally thought that they contained some water, but it was dismissed. Why was it dismissed?
Green: Well, we didn't know really how to handle samples like we do today when we bring back things from space. We do now know that water attaches itself so quickly to material. It just forms a film on things. And so it was originally believed that the rocks, which only contain 50 parts per million in terms of the amount of water, was still contaminated. 50 parts per million – if you took all of the lunar rocks that we have, which is about 500 pounds and you extracted the water, it's still only about a tablespoon's worth. So, still very dry.
Roberts: What does that say then about the potential for establishing a moon base as the previous administration wanted to do as a launching point for going off to Mars? Could you take advantage of some of that water embedded in the rocks to try to sustain life on a more economical basis than to ferry those supplies between the Earth and the moon?
Green: That's a good question. And the scientists are really the ones that are at the forefront of this. We've just taken a major step in understanding the amounts of water that are there. How it circulates, how it might have originated. We're very far from being able to get to the point of determining if man can survive in that environment based on that amount of water. In fact, as I mentioned, what we have discovered is an elevated amount of water – about 1,000 parts per million in the polar region, which is quite large. But still ... as I mentioned, water from our drier deserts have more water in them.
Roberts: Well, it's still a fascinating discovery. We should point out too that further confirmation of this might come on October 9th when the LCROSS mission, the Lunar Crater Observation and Sensing Satellite, will slam a booster on to the moon sending up an enormous cloud of dust that the satellite will float down through to try to determine exactly what's there.