Decades-old mystery about Jupiter’s winds solved

The violent winds in Jupiter’s atmosphere have long fascinated astronomers and planetary researchers. Images from various telescopes and space probes show numerous cloud turbulences and strong east-west jet streams stretching across the planet in distinctive red and white streaks. Now an international team led by lead author Yohai Kaspi of Israel’s Weizmann Institute of Science wants to resolve a decades-old dispute. Using data from the Juno mission, scientists modeled that atmospheric winds rotate as hollow cylinders positioned inside each other at different speeds around the planet’s rotation axis. Previous hypotheses assumed that they extended radially in all directions. They present their results in the specialized journal “Nature Astronomy”.

NASA’s Juno space probe has been closely observing the violent activity in Jupiter’s atmosphere since 2016. The satellite has already orbited Jupiter a total of 55 times and has examined the atmosphere and clouds on the surface using the numerous scientific instruments on board. Astronomers will also track the probe’s radio signal using NASA’s Deep Space Network, a global network of antennas, as Juno flies past Jupiter at nearly 125,000 miles per hour. This corresponds to approximately 85 times the speed of a jet aircraft. They use it to detect small changes in speed, with an accuracy of up to 0.01 millimeters per second. These variations are caused by fluctuations in the planet’s gravitational field and can be used to learn more about the atmosphere.

“We processed the Juno data using a method originally developed for datasets from rocky planets like Earth,” explains Ryan Park, a scientist at the Jet Propulsion Laboratory in Pasadena and co-author, according to a press release. This is the first time such a technique has been applied to a gaseous planet. The authors were able to increase the resolution four times compared to previous models created using data from the two NASA spacecraft Voyager and Galileo.

The new gravitational field measurement data broadly agree with a 20-year-old theoretical prediction that strong east-west currents extend inward from areas of white and red clouds. They also support the idea that atmospheric winds are aligned cylindrically along Jupiter’s rotation axis, like the layers of a cake on a tree. The research team is certain that this means that the evaluation of the new measurement data has put an end to the debate about the nature of Jupiter’s atmosphere, a debate that began in the 1970s.

“All 40 gravity coefficients measured by Juno agree with the model’s predictions, which occur if winds penetrate inward into a cylindrical shape,” says Yohai Kaspi. “When we found that all 40 values ​​matched our calculations exactly, it was like winning the lottery.” The new gravity model not only improves the current understanding of Jupiter’s internal structure and origin, but can also be used to obtain more information in other Researchers are confident that they can obtain planetary atmospheres.