Astronomers spot cyclones at Uranus' pole for first time

Astronomers spot cyclones at Uranus’ pole for the first time

Even at almost 2 billion miles away from the sun, Uranus is still affected by changing seasons and weather just like Earth. On Uranus, though, each season is an epic 21 years long because of its distance from the sun. That makes it an intriguing place to study weather conditions, and recent research by NASA has observed a polar cyclone there.

As the planet is tipped over on its side, its poles aren’t always facing in the right direction to be seen from Earth. But since 2015, astronomers have been able to observe the poles, and to peer into the atmosphere to see what is happening there.

NASA scientists used microwave observations to spot the first polar cyclone on Uranus, seen here as a light-colored dot to the right of center in each image of the planet. The images use wavelength bands K, Ka, and Q, from left. To highlight cyclone features, a different color map was used for each. — NASA scientists used microwave observations to spot the first polar cyclone on Uranus, seen here as a light-colored dot to the right of center in each image of the planet. From left, the images use wavelength bands K, Ka, and Q. To highlight cyclone features, a different color map was used for each. NASA/JPL-Caltech/VLA

While Uranus is usually portrayed as a generally featureless blue ball, when seen using radio telescopes, the pole reveals a swirling cyclone. “These observations tell us a lot more about the story of Uranus. It’s a much more dynamic world than you might think,” said lead author Alex Akins of NASA’s Jet Propulsion Laboratory in a statement. “It isn’t just a plain blue ball of gas. There’s a lot happening under the hood.”

To study the planet, the researchers used the Very Large Array, which is a group of ground-based dishes that work together to act like one large telescope. Using observations from 2015, 2021, and 2022, the researchers were able to see how the atmosphere changed over time. The cyclone occurs due to the movement of warm gas through the atmosphere, which can start to rotate and form a swirl that moves in the same direction as the rotation of the planet.

Researchers saw spinning of the methane clouds at Uranus’ southern pole after the Voyager 2 mission passed by there in the 1980s. But they aren’t sure whether the newly observed cyclone with its core of warm air is the same phenomenon.

“Does the warm core we observed represent the same high-speed circulation seen by Voyager?” Akins asked. “Or are there stacked cyclones in Uranus’ atmosphere? The fact that we’re still finding out such simple things about how Uranus’ atmosphere works really gets me excited to find out more about this mysterious planet.”

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