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Uranus Events - Eclipse and Dark Spot

As summer came to a close in the Midwest, a team of researchers led by SSEC’s Larry Sromovsky used NASA’s Hubble Space Telescope to capture two previously unseen events on Uranus: an eclipse of one of the planet’s moons and the appearance of a dark spot.

Sromovsky and his team observed Ariel, one of Uranus’ moons, as it traveled between the planet and the Sun creating a shadow that scooted across the planet’s surface. This is first time an eclipse has been spotted on Uranus because the planet takes 84 years to orbit the sun and the planet is sideways with respect to its polar axis.

The team also noticed a dark spot in Uranus’ atmosphere. Frequently seen on Neptune, a planet that is similar in size and atmospheric composition, this is the first definitive image of a dark spot on Uranus. Sromovsky says that the spot likely indicates cloud circulation forming a vortex with characteristics similar to hurricanes on Earth.

The eclipse was observed on July 26. The color composite images of the eclipse were created using images take at wavelengths of 750 nanometers (assigned to blue), 770 nanometers (assigned to green) and 790 nanometers (assigned to red). The team saw the dark spot on August 23 and again on August 24. The color composite images of the dark spot Uranus are created using images taken at wavelengths of 550 nanometers (assigned to blue), 658 nm (assigned to green) and 775 nm (assigned to red). The blue image was processed to correct for darkening of the image from center to limb.

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Last Updated:
October 4, 2006
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