Voyager’s Visit to Uranus

The blue-green crescent of a sunlit Uranus, seen by a departing Voyager on January 25, 1986 (NASA)

Voyager 2 may have been the second of NASA’s twin exploration spacecraft but it launched first, 35 years ago today on August 20, 1977. 8 1/2 years later it became the first (and last!) spacecraft to visit the gas giant Uranus, the third largest planet in the Solar System.

Rings Around Uranus

Distant Ringed Uranus

This ghostly image was taken by a Chilean ground-based telescope in 2002. It shows the enigmatic gas giant Uranus in near-infrared light, 7 of its 27 known moons visible. (For a labeled version of this image noting the moons, click here.)

Seventh planet from the sun, Uranus’ year is 84 Earth-years long. Like the other gas giants, Uranus has rings – thirteen, at last count. What makes Uranus especially different among the planets is its unique axial tilt…the entire planet, rings and all, is tipped nearly horizontal along its orbital plane. It’s as if it were “lying down”.

More recently on August 17, 2007 the Hubble Space Telescope captured a photo of Uranus with its rings angled edge-on to Earth. This viewpoint is only possible once every 42 years.

Uranus is approximately 4 times larger than Earth in diameter.

Image: European Southern Observatory