NASA observes a polar cyclone on Uranus for the first time

For the first time, NASA scientists have strong evidence of a polar cyclone on Uranus. By examining radio waves emitted from the ice giant, they detected the phenomenon at the planet’s north pole. 

The findings confirm a broad truth about all planets with substantial atmospheres in our solar system: Whether the planets are composed mainly of rock or gas, their atmospheres show signs of a swirling vortex at the poles.

Scientists have long known that Uranus’ south pole has a swirling feature. NASA’s Voyager 2 imaging of methane cloud tops there showed winds at the polar center spinning faster than over the rest of the pole.

Voyager’s infrared measurements observed no temperature changes, but the new findings, published in Geophysical Research Letters, do.

Using huge radio antenna dishes of the Very Large Array in New Mexico, they peered below the ice giant’s clouds, determining that the circulating air at the north pole seems to be warmer and drier the hallmarks of a strong cyclone. 

Collected in 2015, 2021, and 2022, the observations went deeper into Uranus’ atmosphere than any before.

Uranus is showing off more these days, thanks to the planet’s position in orbit. It’s a long haul around the solar system for this outer planet, taking 84 years to complete a full lap, and for the last few decades the poles weren’t pointed toward Earth.

Since about 2015, scientists have had a better view and have been able to look deeper into the polar atmosphere.

The cyclone on Uranus, compactly shaped with warm and dry air at its core, is much like those spotted by NASA’s Cassini at Saturn. 

With the new findings, cyclones (which rotate in the same direction their planet rotates) or anti-cyclones (which rotate in the opposite direction) have now been identified at the poles on every planet in our solar system except for Mercury, which has no substantial atmosphere.