Leah Siegelman While just studying the swirling waters of the Southern Ocean around Antarctica, she came across a poster image of a cyclone around Jupiter’s north pole, taken by NASA. Juno Spaceship“I looked at it and I was shocked: ‘Wow, this looks like turbulence in the ocean,'” she said.
So Siegelman, a researcher at the Scripps Institution of Oceanography in San Diego, turned to the latest details picture alien planet. She and her team have demonstrated for the first time that a type of convection seen on Earth explains the physical forces and energy sources that create cyclones on Jupiter. (Since air and water are both “fluids,” from a physics standpoint, the same principles apply to the gas giant’s atmosphere and our oceans.) They published their findings today in the journal physical physics.
Jupiter, the 4 trillion-pound elephant in our solar system, creates giant cyclones, large storms that revolve around regions of low pressure. Some are thousands of miles across—as big as the continental United States—with gusts of up to 250 miles per hour. Eight of the largest have been found in Earth’s North Pole and five in the South Pole. Scientists have speculated about their origins for years, but by mapping these storms and measuring their wind speeds and temperatures, Siegelman and her colleagues showed how they actually formed. Small whirling eddies—not so different from the ocean eddies Siegelman was familiar with—appeared everywhere in the turbulent clouds—and then they began to merge with each other. Cyclones grow by constantly eating smaller clouds and drawing energy from them, so they continue to spin, she said.
It’s a clever way to study extreme weather on a planet more than 500 million miles away. “The authors clearly come from the disciplines of meteorology and oceanography. These are the people who are taking this rich literature and applying it in complex ways to planets that are almost inaccessible to us,” said Morgan O’Neill, an atmospheric scientist at Stanford University, who writes for Earth of hurricanes and tornadoes, and applied her work to Saturn.
In particular, O’Neill said, the team of scientists showed how Jupiter’s cyclones, like thunderstorms on Earth, form with a vulgar-sounding name: “moist convection.” Warm, less dense air deep within the planet’s atmosphere gradually rises, while cooler, denser air near the cold vacuum of space drifts downward. This creates turbulence, which can be seen in Jupiter’s swirling, moisture-laden clouds of ammonia.