Neptune's largest moon has an unusual orbit that suggests it formed elsewhere before being captured by the outermost planet's gravity. Triton is the only large moon in the Solar System that moves in the opposite direction to its planet's rotation.
In 1989 the Voyager 2 probe showed scientists close-up views of Triton's ice-covered, relatively crater-free surface.
The English amateur astronomer William Lassell discovered Triton in 1846.
Photo: Triton taken by the Voyager probe (NASA)
In one hundred million years it is predicted that Saturn's rings will disappear. In one billion years, Neptune may develop its own rings when its moon Triton spirals from orbit and disintegrates into countless fragments.
The Voyager 2 probe, launched in 1977, flew by Triton in 1989. The moon's unexpected, miles-high nitrogen geysers proved that geologic activity is possible in the coldest outer reaches of the Solar System.
Triton is the largest moon of the planet Neptune, discovered on October 10, 1846, by English astronomer William Lassell. It is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet's rotation. At 2,700 km in diameter, it is the seventh-largest moon in the Solar System. Because of its retrograde orbit and composition similar to Pluto's, Triton is thought to have been captured from the Kuiper belt. Triton has a surface of mostly frozen nitrogen, a mostly water ice crust, an icy mantle and a substantial core of rock and metal. The core makes up two-thirds of its total mass. Triton has a mean density of 2.061 grams per cubic centimetre (0.0745 lb/cu in) and is composed of approximately 15–35% water ice.
Triton is one of the few moons in the Solar System known to be geologically active. As a consequence, its surface is relatively young, with a complex geological history revealed in intricate and mysterious cryovolcanic and tectonic terrains. Part of its crust is dotted with geysers thought to erupt nitrogen. Triton has a tenuous nitrogen atmosphere less than 1/70 000 the pressure of Earth's atmosphere at sea level.
This entry is from Wikipedia, the user-contributed encyclopedia. If you find the content in the 'About' section factually incorrect, defamatory or highly offensive you can edit this article at Wikipedia.
BBC © 2012 The BBC is not responsible for the content of external sites. Read more.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.
