Winds whirl and clouds churn 2 billion miles away in the atmosphere of Uranus, forming a dark vortex large enough to engulf two-thirds of the United States. Astronomers at the University of Wisconsin-Madison used NASA's Hubble Space Telescope to take the first definitive images of a dark spot on Uranus.
The elongated feature measures 1,100 miles by 1,900 miles (1,700 kilometers by 3,000 kilometers). This three-wavelength composite image was taken with Hubble's Advanced Camera for Surveys on August 23, 2006.
Photo : NASA ESA L. Sromovsky and P. Fry (University of Wisconsin)
and H. Hammel (Space Science Institute) and K. Rages (SETI Institute)