Hubble Spies Tiny Moons Circling Uranus

These images, taken with the NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys (ACS), show several faint moons circling Uranus, including a newly detected moon and a rediscovered satellite. The planet's ring system can also be seen.

The arrow in the frame at right points to one of two newly discovered moons, among the smallest moons yet found around Uranus. The moon is temporarily designated as S/2003 U 1 until the International Astronomical Union (IAU) formally approves its discovery. S/2003 U 1 is orbiting 60,600 miles (97,700 km) away from the planet. If the satellite is as dark as Uranus's other moons, it is 10 miles (16 km) across, about the size of San Francisco. The Hubble telescope spotted this moon orbiting between the moons Puck, the largest satellite found by Voyager, and Miranda, the innermost of the five largest Uranian satellites. Astronomers previously thought this region was empty space. S/2003 U 1 whirls around the gas giant planet in 22 hours and 9 minutes.