Hubble Discovers Dark Cloud in the Atmosphere of Uranus
Just as we near the end of the hurricane season in the Atlantic Ocean, 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. The research team found the dark spot again on August 24. The inset image shows a magnified view of the spot with enhanced contrast. Uranus's north pole is near the 3 o'clock position in this image. The bright band in the southern hemisphere is at 45 degrees south.