Astronomers at the W.M. Keck Observatory on Mauna Kea in Hawaii have discovered a warm polar vortex at Saturn’s South Pole. A vortex is a persistent, large-scale weather pattern. It’s the first warm polar vortex discovered in the solar system.
The images are the sharpest thermal views of Saturn ever taken from Earth’s surface. Using the Keck 1 telescope, infrared images captured a large-scale weather pattern in the upper atmosphere of Saturn that is similar to the jet stream on Earth. On Earth, the Arctic Polar Vortex is normally located over eastern North America in Canada and plunges cold arctic air southward to the northern Plains in the United States. Earth’s cold Antarctic Polar Vortex, centered over Antarctica, traps air and creates unusual chemistry, like the effects that create the hole in the ozone.
Polar vortices on Earth, Jupiter, Mars, and Venus are colder than their surroundings. On Saturn, the polar vortex is warm air. Scientists believe the heat at the South Pole may have something to do with Saturn’s Southern Hemisphere being tilted toward the sun for the last 18 years. It doesn’t explain why the heating is isolated in a compact area directly over the South Pole when all the southern latitudes face the sun and should have a gradual warming in the southern latitudes.
The warm polar cap is believed to be the highest temperatures on Saturn. Saturn’s normal temperature is about –300 degrees Fahrenheit. At its warmest spot, right at the South Pole, the temperature reaches –188 degrees. It’s a very compact spot of warmth. The temperatures do not gradually increase to the South Pole, but suddenly increase over 100 degrees. Astronomers don’t know why there isn’t a gradual warming of the atmosphere in the southern latitudes that increases toward the South Pole. The abrupt changes cannot be explained so far.