Geometric clusters of cyclones churn over Jupiter’s poles, spacecraft shows


Fri, Mar 09, 2018 - Page 7

Jupiter’s poles are blanketed by geometric clusters of cyclones and its atmosphere is deeper than scientists suspected.

These are just some of the discoveries reported by four international research teams on Wednesday, based on observations by NASA’s Juno spacecraft circling Jupiter.

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 350kph.

The massive storms have not changed position much — or merged — since observations began.

Italian National Institute for Astrophysics team leader Alberto Adriani said he 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.

“We were wrong about it,” he said via e-mail.

Instead, they found an octagon-shaped grouping over the north pole, with eight cyclones surrounding one in the middle, and a pentagon-shaped batch over the south pole. Each cyclone measures several thousand kilometers across.

The fifth planet from the sun, gas giant Jupiter is by far the largest planet 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, published in this week’s Nature, finds that Jupiter’s crisscrossing east-west jet streams actually penetrate thousands of kilometers beneath the visible cloud tops.

Refined measurements of Jupiter’s uneven gravity field enabled the Weizmann Institute of Science researcher Yohai Kaspi in Rehovot, Israel, and his colleagues to calculate the depth of the jet streams at about 3,000km.

“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 e-mail.

By better understanding these strong jet streams and the gravity field, Kaspi said scientists can better decipher the core of Jupiter.

A similar situation might be occurring at other big gas planets like Saturn, where the atmosphere could be even deeper than Jupiter’s, he said.