Clouds circle around the south pole of Saturn in this image from the Cassini spacecraft. The vortex is a giant hurricane, with the warmest temperatures yet seen on Saturn. This image shows smaller storms popping up inside the vortex, which is as wide as Earth. Winds on its edge reach 350 miles per hour. [NASA/JPL]
Moon and Saturn
The coldest temperatures ever seen here on Earth were recorded at a research station in Antarctica, not far from the south pole. On the planet Saturn, though, the south pole is the site of the warmest temperatures yet recorded — about a hundred degrees warmer than at the equator.
That hotspot is inside the south polar vortex — a hurricane-like storm that’s as wide as Earth. It has a large central “eye,” just as hurricanes do, that’s surrounded by two walls of clouds. Clouds in the outer wall are about 20 miles high, while those in the inner wall are twice as high. And winds at the edge of the vortex reach speeds of about 350 miles per hour — twice as strong as the most powerful hurricanes on Earth.
Like hurricanes, the vortex must be powered by heat from below it. On Earth, that heat comes from the oceans. But Saturn has no oceans, so scientists are trying to pinpoint the source of the vortex’s heat. And they’re also trying to understand why the heat breaks through only at the south pole — creating a hotspot in Saturn’s cold atmosphere.
Look for Saturn quite low in the east about 45 minutes before sunrise tomorrow. It looks like a moderately bright star. It’s a bit tough to see through the glow of early dawn, but the crescent Moon is close to the right of Saturn, helping you pick out the giant planet. Brilliant Venus, the “morning star,” stands well above them, completing a beautiful tableau in the dawn sky.
Script by Damond Benningfield, Copyright 2012
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