Geometric clusters of cyclones churn over Jupiter’s poles, Juno probe finds


Geometric clusters of cyclones encircle Jupiter’s poles and its atmosphere is deeper than scientists had suspected, four international research teams reported Wednesday, based on observations by NASA’s Juno spacecraft.

One group uncovered a constellation of nine cyclones over Jupiter’s north pole and six over the south pole. The wind speeds exceed Category 5 hurricane strength in places, reaching 220 mph (350 kph).

The massive storms haven’t changed position much since observations began.

Team leader Alberto Adriani of Italy’s National Institute for Astrophysics in Rome was surprised to find such complex structures. Scientists thought they would find something similar to the six-sided cloud system spinning over Saturn’s north pole.

Instead, they found an octagonal grouping over the north pole, with eight cyclones surrounding one in the middle, and a pentagonal batch over the south pole. Each cyclone is thousands of kilometers across.

The fifth planet from the sun, Jupiter is by far the largest in our solar system. Launched in 2011, Juno has been orbiting Jupiter since 2016 and peering beneath the thick ammonia clouds. It is only the second spacecraft to circle the planet; Galileo did it from 1995 to 2003.

Another of the studies in this week’s journal Nature finds that Jupiter’s crisscrossing east-west jet streams actually penetrate far beneath the visible cloud tops. Refined measurements of Jupiter’s uneven gravity field enabled the Weizmann Institute of Science’s Yohai Kaspi in Rehovot, Israel, and his colleagues to calculate the depth of the jet streams at about 3,000 km (1,865 miles).

“The result is a surprise because this indicates that the atmosphere of Jupiter is massive and extends much deeper than we previously expected,” Kaspi said in an email.

By better understanding these strong jet streams and the gravity field, Kaspi said, scientists can better decipher the core of Jupiter. A similar situation may be occurring at other gas giants like Saturn, where the atmosphere could be even deeper than Jupiter’s, he said.

Jonathan Fortney of the University of California, Santa Cruz, who was not involved in the research, called the findings “extremely robust” and said they show that “high-precision measurements of a planet’s gravitational field can be used to answer questions of deep planetary dynamics.”

Using similar techniques, Juno could help scientists determine the depth of Jupiter’s Great Red Spot, a colossal swirling storm, Fortney said in a companion article in the journal.

NASA’s Jet Propulsion Laboratory researchers Glenn Orton and Fachreddin Tabataba-Vakili, who both took part in the cyclone study, said all these new discoveries “show Jupiter from a new perspective” unseen before Juno.

“We cannot say how many mysteries are left to uncover,” they wrote in an email. “We are already finding way more fascinating results than we ever expected!”