Scientists probe \'hot spots\' on Jupiter

Scientists say they have new clues about a phenomenon on Jupiter dubbed "hot spots," cloudless patches providing a window deep into the planet's atmosphere. Data from the Cassini spacecraft orbiting the giant planet is providing data helping astronomers understand exactly how these clearings form and why they're only found near the planet's equator, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Thursday. The findings suggest the hot spots in Jupiter's atmosphere are created by a phenomenon known as a Rossby wave, a pattern also seen in Earth's atmosphere and oceans. The wave responsible for the hot spots glides up and down through layers of the atmosphere like a carousel horse on a merry-go-round, the researchers said. On Earth, Rossby waves play a major role in weather, such as when a blast of frigid Arctic air suddenly dips down and freezes Florida's crops. That happens when a Rossby wave is interacting with the polar jet stream and sending it off its typical course, the researchers said. "This is the first time anybody has closely tracked the shape of multiple hot spots over a period of time, which is the best way to appreciate the dynamic nature of these features," David Choi at NASA's Goddard Space Flight Center in Greenbelt, Md., said. The researchers used Cassini to examine the daily and weekly changes in the sizes and shapes of the Jupiter hot spots, each of which covers more area than North America on average. The wave responsible for the hot spots circles the planet west to east, gliding up and down in the atmosphere to occasionally create the deep, clear windows into a normally unseen layer of Jupiter's atmosphere, they said.