Lick that!

摘要

What, prithee, is awash with seas but hath no water? The answer, of course, is the moon. From the Ocean of Storms to the Bay of Rainbows, it is covered with features that are aqueous in name but not in nature. These lava plains, the result of meteoritic bombardment around 4 billion years ago, are all as dry as dust. Yet the hope remains that perhaps the riddle is not quite right, and that a little water (or, at least ice) might exist on the Earth's neighbour-perhaps enough to sustain a permanently manned moonbase, should anyone ever decide to build one.rnThat hope is focused at the moment on craters near the moon's poles, particularly one called Shackleton which has the south lunar pole within it. The location of these craters means that parts of their floors never see direct sunlight. So, if comets have landed there (and, given the craters' ages, the odds are that several will have), some of the ice carried by such dirty celestial snowballs might be preserved in the permanent shadow cast by the craters' walls.