Uranus has Bizarre Weather

by Nancy Atkinson on October 18, 2012

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New infrared images of Uranus show details not seen before. Credit: NASA/ESA/L. A. Sromovsky/P. M. Fry/H. B. Hammel/I. de Pater/K. A. Rages

Here’s the scene: a thick, tempestuous atmosphere with winds blowing at a clip of 900 km/h (560 mph); massive storms that would engulf continents here on Earth, and temperatures in the -220 C (-360 degree F) range. Sounds like a cold Hell, but this is the picture emerging of the planet Uranus, revealed in new high-resolution infrared images from the Keck Observatory in Hawaii, exposing in incredible detail the bizarre weather of a planet that was once thought to be rather placid.

“My first reaction to these images was ‘wow’ and then my second reaction was ‘WOW,’” said Heidi Hammel, a co-investigator on the new observations. “These images reveal an astonishing amount of complexity in Uranus’ atmosphere. We knew the planet was active, but until now much of the activity was masked by noise in our data.”

Voyager 2′s view of Uranus. Credit: NASA

With its beautiful blue atmosphere, Uranus can seem rather tranquil at first glance. Even the flyby of Voyager 2 in 1986 revealed a rather “bland” blue ball. But coming into focus now with the new are large weather systems, and even though they are probably much less violent than storms on Earth, the weather on Uranus is just…bizarre.

“Some of these weather systems,” said Larry Sromovsky, from the University of Wisconsin-Madison who led the new study using the Keck II telescope, “stay at fixed latitudes and undergo large variations in activity. Others are seen to drift toward the planet’s equator while undergoing great changes in size and shape. Better measures of the wind fields that surround these massive weather systems are the key to unraveling their mysteries.”

Sromovsky, Hammel and their colleagues are using new infrared techniques to deliver some of the “most richly detailed views of Uranus yet obtained by any instrument on any observatory. No other telescope could come close to producing this result,” Sromovsky said.

What they are seeing are previously undetected, small but widely distributed weather feature, and they hope the movements of these features can help make sense of the planet’s odd pattern of winds.

They observed a scalloped band of clouds just south of Uranus’ equator and a swarm of small convective features in the north polar regions of the planet. Features like this don’t seem to be in the southern polar regions, but are similar to the types of “popcorn” –type clouds seen on Saturn. Uranus’ north pole is not visible from Earth night now, but when it does come into view, the researchers wouldn’t be surprised to see a polar vortex feature similar to what has been seen at Saturn’s south pole.

The driver of these features must be solar energy because there is no other detectable internal energy source.

“But the Sun is 900 times weaker there than on Earth because it is 30 times further from the Sun, so you don’t have the same intensity of solar energy driving the system,” said Sromovsky. “Thus the atmosphere of Uranus must operate as a very efficient machine with very little dissipation. Yet the weather variations we see seem to defy that requirement.”

One possible explanation, is that methane is pushed north by an atmospheric conveyor belt toward the pole where it wells up to form the convective features visible in the new images. The phenomena may be seasonal, the team said, but they are still working on trying to put together a clear seasonal trend in the winds of Uranus.

“Uranus is changing,” he said, “and there is certainly something different going on in the two polar regions.”

The images were released at the American Astronomical Society’s Division for Planetary Sciences meeting taking place this week.

Source: University of Wisconsin-Madison

About 

Nancy Atkinson is Universe Today's Senior Editor. She also works with Astronomy Cast, and is a NASA/JPL Solar System Ambassador.

i just October 18, 2012 at 1:05 PM

“Uranus is changing,” he said.

katesisco October 18, 2012 at 8:00 PM

If we consider that the source of the high-energy csmic rays found by J Wefel of Louisiana State U in nov 2008 is Proxima Centauri on a long orbit that breaks into the Oort cloud before leaving, it would fit the requirement that the electrons be within 1 parsec.
I theorize this occurance is periodic and recently has lost energy; prior to 20,000 y ago all planets were compressed as the energy pushed over the planets to the sun. As the energy rode over the planets in their orbits it would leave them to freely blow out their heated cores in the cold of cosmic space. The heliosphere would regain system-size when the energy lifted.
The compression now fails to reach further than to Mars. The outer gas giants are almost always expanded during this 5,000 y event of several years duration. But they would be receiving a stronger energy than the inner rocky planets.
I propose this core heating is the unknown variable in our source of planet heat.

ren00r October 19, 2012 at 6:49 AM

What? Proxima is not orbiting our sun. Nobody requires any electrons to be within 1 parsec. Do you understand the difference between solid material (like rock) and gas (like air)? What are you talking about?

SJStar October 19, 2012 at 2:04 PM

Personal theories are inadvisable here…

Jeffrey Scott Boerst October 21, 2012 at 1:51 AM

…as by definition they’re uninformed and ludicrous, thus worthless.

Rick Holcomb October 19, 2012 at 3:58 PM

C’mon people. This person is just nuts. It happens.

Tim Amato October 19, 2012 at 3:38 AM

The south pole looks like a nice place to land.

SJStar October 19, 2012 at 2:03 PM

It is being caused by climate change I’d say…

Jeffrey Scott Boerst October 20, 2012 at 10:46 AM

You’re the obvious expert on all the things that come out of Uranus so I’ll go with your lead on this one…..

pollydextrous October 19, 2012 at 6:11 PM

That’s some frightful wind around Uranus, let’s give it a minute before we launch a probe into it.

Sorry, no one had touched the puerile side yet.

Peristroika October 19, 2012 at 6:22 PM

How is this new telescope able to image Uranus’s clouds so much more effectively than it’s contemporaries and predecessors?

magnus.nyborg October 21, 2012 at 10:26 AM

Infrared imaging, possibly even narrowband infrared imaging.
Uranus is very bland at visual wavelenghts. almost uniform. But at infrared wavelengths around 10000Å (close to a prominent Methane-line) significantly more details show. Combined with adaptive optics that allow a greater resolution even through the atmosphere, Uranus have been extensively studies at Keck for more than a decade now.

Jeffrey Scott Boerst October 20, 2012 at 10:48 AM

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