WHERE there's water, there's life. Among astrobiologists it is almost a mantra. On Earth, they point out, we have found life flourishing in searing heat and shattering cold, bright light and pitch darkness. As long as there's liquid water, living things will find a way. And what's true here could very well be true elsewhere in the Universe. You want alien life? Then look for alien water.
That's why astronomers around the world are straining to pick up even the faintest cosmic traces of the precious liquid. Perhaps there are miniature oases in Mars's frozen desert, warmed from below. Perhaps we'll find Earth-like planets orbiting far-off stars at just the right distance to allow water to flow (see "Alien haven").
And perhaps there is a perfectly good alien ocean right on our doorstep. One, moreover, that contains enough water to fill all of the Earth's ocean basins and then ...
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