Uranus' elusive rings glow in new telescope heat view

Stand back, Saturn. Uranus has some rings to show off, too.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
2 min read

This composite image shows Uranus' atmosphere, and thermal emissions from the rings, as seen by the ALMA array. The yellow spot is the north pole region of the tilted planet.

UC Berkeley/Edward Molter/Imke de Pater

Saturn may hog all the glory when it comes to rings, but humble Uranus wants in on the action. New heat images of the blue planet, the seventh from the sun, really make its rings pop out.

The thermal views come from the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Southern Observatory's Very Large Telescope (VLT) in Chile. 

Scientists were able to take the rings' temperature for the first time, which clocks in at 77 Kelvin, about -320 degrees Fahrenheit.

Enlarge Image

Uranus' ring system as seen in different wavelengths by the ALMA and VLT telescopes.

Edward Molter/Imke de Pater/Michael Roman/Leigh Fletcher

Uranus' rings are notoriously hard to spot. We didn't even know they existed until 1977, and since then the official ring count has climbed to 13.  

The new data confirms that Uranus' brightest ring, called the epsilon ring, is different from other known planetary rings. It's doesn't have the usual accumulations of smaller, dust-size particles and is instead made up of rocks the size of golf balls and larger.

"Something has been sweeping the smaller stuff out, or it's all glomming together. We just don't know," said Edward Molter, a graduate student at the University of California, Berkeley, and co-author of a paper on the rings published in The Astronomical Journal. "This is a step toward understanding their composition and whether all of the rings came from the same source material, or are different for each ring." 

There are several theories about how Uranus got its narrow, elusive rings. They could be busted-up pieces of moons, broken asteroids or even material left over from the planet's birth billions of years ago. 

With the new temperature measurement, at least one lingering Uranus ring question has now been answered.

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