NASA’s Cassini Space Probe has discovered another new ocean on Saturn: the Enceladen Ocean. The name is lovely and the place is nifty, but there’s not much chance of visiting it soon. It’s located on Enceladus, one of Saturn‘s 66 known moons. While Enceladus itself has been familiar to us since the time it was first spotted in 1789, the discovery of its ocean, is a game-changer.
Enceladus has always been thought of as one of the more remarkable moons of Saturn. For one thing, it’s dazzlingly bright. The percentage of sunlight that any body in the solar system reflects back is known as its albedo. For all the silvery brilliance of a full moon on a cloudless night, the albedo of our own drab satellite is a muddy 12%, owing mostly to the gray dust that covers it. The albedo of Enceladus, on the other hand, approaches a mirrorlike 100%. What this means is that the surface is covered with ice crystals — and, what’s more, that those crystals get regularly replenished.
But the big question was always, how much water is there? A lake? A sea? A globe-girdling ocean? The more there is, and the more it churns and circulates, the likelier it is that it could cook up some life. The answer to that question finally came this week, thanks to Cassini images of stress cracks in the ice on the Enceladen surface — known as tiger stripes. Cassini scientists were particularly interested in a pair of tiger stripes in the moon’s warmer polar regions, since they are very deep and comparatively wide and seem to change over time. The new images revealed that the cracks indeed widen and narrow, and do so more than once known.
The fact that Enceladus becomes as distorted as it does is a powerful indicator of just how much water it contains. A watery world is a flexible world, and for Enceladus to be so elastic, it must contain a very large local ocean or perhaps even a globe-girdling one. Portions of that ocean may not just be bathwater warm, but outright hot.
And Enceladus is not the only moon in the solar system that is home to such a feature. Jupiter’s Europa is even more certain to contain a global ocean of its own. On both worlds, organics plus water plus warmth plus time could be more than enough to get life going. The search for life elsewhere may be closer to home than ever imagined.
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