Astronomy Picture of the Day Index - Solar System: Uranus

APOD: 1997 November 15 - Uranus: The Tilted Planet
Explanation: Uranus is the third largest planet after Jupiter and Saturn. This picture was snapped by the Voyager 2 spacecraft in 1986 - the only spacecraft ever to visit Uranus. Uranus has many moons and a ring system. Uranus is composed mostly of rock and ices, but with a thick hydrogen and helium atmosphere. Uranus is peculiar in that its rotation axis is greatly tilted and sometimes points near the Sun. It remains an astronomical mystery why Uranus' axis is so tilted. Uranus and Neptune are very similar.

APOD: 1998 October 20 - Infrared Uranus
Explanation: The Sun's third largest planet usually looks quite dull. Uranus typically appears as a featureless small spot in a small telescope or a featureless large orb in a large telescope. Last August, however, the Hubble Space Telescope was able to photograph Uranus in infrared light, where the distant planet better shows its unusual clouds, rings, and moons. Recent analysis indicates that clouds seen here in orange appear to circle Uranus at speeds in excess of 500 kilometers per hour. Comparisons to earlier photographs show a slight precession shift in the brightest of Uranus' rings. Several of Uranus' numerous small moons are visible.

APOD: 1996 April 30 - Uranus' Ring System
Explanation: The rings of Uranus are thin, narrow, and dark compared to other planetary ring systems. Brightened artificially by computer, the ring particles reflect as little light as charcoal, although they are really made of ice chucks darkened by rock. This false-color, infrared picture from the Hubble Space Telescope taken in July 1995 shows the rings in conjunction to the planet. The infrared light allows one to see detail in different layers of Uranus' atmosphere, which has been digitally enhanced with false color. Three other planets in our Solar System are known to have rings: Jupiter, Saturn, and Neptune. Four of Uranus' moons are visible outside the ring plane. The rings of Uranus were discovered from ground-based observations in 1977.