Hundred-year storms? That's how long they last on Saturn

[Kamaji]

Hundred-year storms?  That's how long they last on Saturn

Megastorms leave marks on Saturn's atmosphere for centuries

Date:  August 11, 2023
Source:  University of California - Berkeley
Summary:  Megastorms regularly appear on Saturn, marring the relatively bland surface before disappearing. But radio observations show that the storms have long-lasting effects deeper in the atmosphere, in particular in the distribution of ammonia. Using NRAO's Very Large Array, astronomers see such impacts from storms that happened hundreds of years ago. The findings will help explain the differences between storms on the gas giants Saturn and Jupiter.

The largest storm in the solar system, a 10,000-mile-wide anticyclone called the Great Red Spot, has decorated Jupiter's surface for hundreds of years.

A new study now shows that Saturn -- though much blander and less colorful than Jupiter -- also has long-lasting megastorms with impacts deep in the atmosphere that persist for centuries.

The study was conducted by astronomers from the University of California, Berkeley, and the University of Michigan, Ann Arbor, who looked at radio emissions from the planet, which come from below the surface, and found long-term disruptions in the distribution of ammonia gas.

The study was published today (Aug. 11) in the journal Science Advances.

Megastorms occur approximately every 20 to 30 years on Saturn and are similar to hurricanes on Earth, although significantly larger. But unlike Earth's hurricanes, no one knows what causes megastorms in Saturn's atmosphere, which is composed mainly of hydrogen and helium with traces of methane, water and ammonia.

"Understanding the mechanisms of the largest storms in the solar system puts the theory of hurricanes into a broader cosmic context, challenging our current knowledge and pushing the boundaries of terrestrial meteorology," said lead author Cheng Li, a former 51 Peg b Fellow at UC Berkeley who is now an assistant professor at the University of Michigan.

Imke de Pater, a UC Berkeley professor emerita of astronomy and of earth and planetary sciences, has been studying gas giants for over four decades to better understand their composition and what makes them unique, employing the Karl G. Jansky Very Large Array in New Mexico to probe the radio emissions from deep inside the planet.

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Source:  https://www.sciencedaily.com/releases/2023/08/230811172145.htm