Bright Spot in Uranus’s Atmosphere

Australian amateur astronomer Anthony Wesley took these composite images of Uranus on September 19th and October 2nd, showing the dramatic appearance of a bright storm on a planet that normally displays only a diffuse bright polar region. The color is from RGB filters, but the spot appears in infrared.
Anthony Wesley

Amateur astronomers have confirmed the presence of a large, bright storm cloud on Uranus.

There have been many dull moments on our solar system’s blue-green ice giant, but these days Uranus is pretty hopping. For the past few years, astronomers have seen the Uranian weather ramp up, producing spots, scalloped edges, and other cloud features.

Recent storms have been so large that amateur astronomers are spotting them, too. When Imke de Pater (University of California, Berkeley) and her colleagues detected eight large storms in the planet’s northern hemisphere on August 5th and 6th, several amateurs also started looking.

Among the successful observers was Australian amateur Anthony Wesley, who caught the bright spot in the images at right on October 2nd. French amateur Marc Delcroix also saw it in infrared observations he took on October 3rd and 4th. (Delcroix went looking after he processed images by amateur Régis De-Bénedictis and others from September and October that revealed the storm.)

The storm clouds are likely so bright due to high reflectivity. They’re probably made of condensations of methane ice or other compounds.

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