ScienceShot: Icy Europa Looking More Inviting

Scientists analyzing decades-old images with new eyes are seeing signs that Jupiter's radiation-blasted moon Europa may harbor giant under-ice "lakes" that could sustain life. Europa doesn't lack for the prime ingredient for life: liquid water. The moon has a global ocean hundreds of kilometers deep that is covered by a layer of ice perhaps 10 or 20 kilometers thick. But a team of glaciologists and planetary scientists report online today in Nature that—judging by the way erupting volcanoes on Earth disrupt their ice caps—huge pools of water must lie as little as 3 kilometers beneath the surface. On Europa, rather than a volcano, a rising plume of warmer but still solid ice would drive ice melting a few kilometers beneath the surface. And then a briny slush of ice would rise from the resulting lake and disrupt the surface to form Europa's long-known chaotic terrains of jumbled ice blocks. Direct confirmation of giant Europan lakes each holding the combined volume of North America's Great Lakes must await radar probing by a multibillion-dollar spacecraft that is still stuck on planetary scientists' wish list.

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