Astronomers recorded the first cyclone at the north pole of Uranus

Astronomers using the Carl G. Jansky Very Large Array in New Mexico have detected a bright, compact spot centered at Uranus’ north pole at several wavelengths. This feature probably indicates the presence of a polar cyclone and shows similarities to polar features observed on other giant planets in our solar system.

Scientists have long known that Uranus’ south pole has a twisted shape. NASA’s Voyager 2 imaging of the tops of methane clouds showed that the winds at the polar center rotate faster than over the rest of the pole. Voyager’s infrared measurements showed no change in temperature, but new results indicate that the circulating air at Uranus’ north pole appears warmer and drier.

Using the huge radio antenna dishes of the Very Large Array in New Mexico, Dr. Alex Akins of NASA’s Jet Propulsion Laboratory and his colleagues looked beneath the ice giant’s clouds and determined that observations collected in 2015, 2021 and 2022 penetrated Uranus’ atmosphere deeper than ever before.

“These observations tell us much more about the history of Uranus,” Dr. Akins said. – It’s a much more dynamic world than you think. It’s not just a blue gas ball. “There’s a lot going on under the hood.”

For this outer planet, it’s a long way around the solar system, taking 84 years to come full circle, and for the past few decades, the poles have not been pointing toward Earth. Since about 2015, astronomers have seen better and have been able to look deeper into the polar atmosphere.

The cyclone on Uranus is a compact shape with warm and dry air at its core, very similar to those discovered by the Cassini spacecraft on Saturn. Thanks to new discoveries, cyclones (which rotate in the same direction as their planet) or anticyclones (which rotate in the opposite direction) have now been identified at the poles of every planet in our solar system, except Mercury, which has no contained atmosphere.

But unlike terrestrial hurricanes, cyclones on Uranus and Saturn do not form over water (neither planet has liquid water), and they do not drift; they are locked at the poles.

Astronomers will keep a close eye on the development of this newly discovered Uranus cyclone in the coming years.

“Does the warm core we observe represent the same high-speed circulation that Voyager observed? – Dr. Akins said. – Or is there stacked cyclones in Uranus’ atmosphere? The fact that we’re still learning such simple things about how Uranus’ atmosphere works really inspires me to learn more about this mysterious planet.

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