Water Found in Sunlight and Shadow on the Moon

For most of the space age, the moon has been considered a waterless world. In recent years, however, a steady drip-drip of discovery has shown that at least some parts of the moon—such as the large, permanently shadowed craters at its poles—contain significant deposits of water. This week, two new studies published in Nature Astronomy turn on the tap a bit more to the prospect of an unexpectedly watery moon.

The timing is good for NASA and other space agencies now planning ambitious human missions of lunar exploration and even...