Polar Cyclone Spotted Swirling on Uranus’ North Pole

A northern vortex was discovered in Uranus. It was detected using telescopes in New Mexico.

Vortex in Uranus' North Pole

Substantial proof that a cyclone is moored at Uranus' north pole has been found by the detection of a vortex of comparatively warm air circulating beneath the planet's clouds, Space.com reported.

The discoveries strengthen the argument that Uranus is not as inert an atmosphere as it first appeared when NASA's Voyager 2 probe passed by the "ice giant" in January 1986.

The detection of heat emission in radio waves picked up by astronomers using the Very Large Array (VLA) of radio telescopes in New Mexico led to identifying a northern vortex on Uranus.

The atmospheric circulation and temperature change in this polar cap were detected during observations of Uranus by the VLA in 2015, 2021, and 2022. At 80 degrees latitude, the VLA discovered a "dark collar" encircling the planet, mirroring a brilliant collar found by Voyager 2 around the planet's southern pole, which is thought to be a denser region of the atmosphere. The VLA discovered a bright patch inside this dense collar, indicating that the vortex's core is several degrees warmer than the surrounding area, where temperatures can fall as low as minus 370 degrees Fahrenheit (minus 224 degrees Celsius). This kind of bright, warmer patch is a fairly common cyclone trait.

The leader of the observations, Alex Atkins of NASA's Jet Propulsion Laboratory in Southern California, said in a statement that these observations provide a wealth of new information on Uranus. The world is far more dynamic than you would imagine.

In contrast to cyclones on Earth, the polar vortex on Uranus is made of ices of methane, ammonia, and hydrogen sulfide. Furthermore, the storm doesn't move; instead, it stays anchored to the pole. Currently, not much else is known about it.

Polar Vortices in Uranus

Polar vortices have been previously seen on Venus, Earth, Mars, Jupiter, Saturn, Uranus (at its south pole), and Neptune. They appear to be a common feature of all planets with atmospheres, at least in our solar system. Although the specifics vary depending on the globe, high-altitude atmospheric jet streams are assumed to cause these vortices' development.

It was discovered by Voyager 2 that Uranus' south pole experiences fluctuations in wind speeds that can approach 560 mph (900 kph) and are compatible with the presence of a polar vortex. However, Voyager 2 could not observe the planet's north pole to determine whether a vortex existed. The fact that it has been challenging to observe either of Uranus' poles from Earth up until recently adds to the dearth of up-close evidence. This is due to the 97.8-degree tilt at which Uranus orbits the sun. Since it is essentially "rolling" around the sun, we were able to observe the planet's equatorial zone for a considerable amount of time.

However, since 2015, Uranus has rotated around the sun sufficiently for us to see its north pole more clearly as the planet moves into its northern spring. The Hubble Space Telescope discovered the first signs of a polar cyclone in 2018 and 2022 when it noticed a bright, hazy cap above Uranus' north pole.

A major science objective is to watch and comprehend Uranus' polar cyclones. Atkins and his colleagues intend to investigate the north polar vortex for many years to see if and how it might change over time. As northern spring has progressed, there are signs that the warm core has brightened.

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