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Moon and Saturn

May 13, 2011

More than 10,000 geysers, mud pots, and steaming pools bubble across the Yellowstone region of the American west. They're powered by the heat from molten rock far below the surface.

But Old Faithful and Yellowstone's other natural wonders are puny compared to a land of geysers on Enceladus, one of the moons of Saturn. Its geysers shoot water and ice dozens of miles into space, adding fresh material to one of Saturn's rings. And their power source is more than twice as strong as Yellowstone's.

The geysers come from long, wide cracks around the moon's south pole. A recent analysis showed that the total amount of heat from the region is the equivalent of more than 15 gigawatts -- as much power as a dozen nuclear reactors.

That's more than planetary scientists had expected, and it's left them a little puzzled about the source of so much heat. The interior of Enceladus is probably heated by a gravitational tug of war between Saturn and one of the planet's other moons. But models of how that works suggest that it should provide only a fraction as much heat.

That much heat increases the odds that an ocean of liquid water could lie beneath the moon's icy crust -- providing plenty of material for its powerful geysers.

Saturn is in good view near our own moon tonight. It looks like a bright golden star a little to the upper left of the Moon at nightfall. The true star Spica is to their lower left. More about this lineup tomorrow.


Script by Damond Benningfield, Copyright 2011


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