NASA' s Lunar Reconnaissance Orbiter has settled into a circular 31-mile-high orbit around the moon to begin mapping the surface and looking for minerals. Scientists have been expecting to find hydrogen,  which may mean there is frozen water on the moon. But if the early results are an indication of what is to come, the mission may end up generating more questions than it answers.

For starters, LRO has indeed found hydrogen, but some of the locations where it has turned up are places that, on the surface anyway, are not cold enough for ice to exist. 

"There is hydrogen near the lunar south polar region," LRO scientist Richard Vondrak told reporters yesterday, but added that it is not confined to craters that never see sunlight. 

Scientists theorize that the hydrogen outside the craters may be coming from buried ice. "You may have had water deposited, or some other hydrogen-bearing compound like methane or ammonia, that was deposited (by) a comet or some other event and then it was promptly buried," Vondrak said. 

More information will be coming next month when LRO's companion spacecraft LCROSS hurls a 2.5-ton dead weight into one of the moon's shadowed craters so scientists can glimpse ejected material for signs of water.