Distant planet is blue and beautiful

The image is constructed to show methane as blue

By Dr David Whitehouse BBC News Online science editor

The Subaru Telescope on Hawaii has produced a stunning image of Uranus.

Two of planet's moons are visible, as is its remarkable dust ring.

This picture of the seventh major body from the Sun is not only visually appealing, it is helping astronomers probe the composition of the planet's atmosphere.

It is actually a composite image, combining infrared light in three different regions of the spectrum. This means that the actual appearance of the planet and its rings is not what we would normally see.

In the colour scheme, methane, the dominant component of the Uranus atmosphere, shows up as blue.

Uranus is a gas-giant world that is difficult to study from the Earth even with the largest telescopes. It has been visited by a spaceprobe only once when the Voyager craft passed it in 1986. There are no plans as yet to return to the world.

Not a comet

The new image adds to the Subaru Telescope's growing reputation for producing stunningly beautiful images of the cosmos.

Subaru: Advanced eye on the cosmos

The planet itself, its ring system, and two of its satellites, Miranda (top) and Ariel (bottom-left), were imaged by the telescope's Coronagraphic Imager as part of its programme of commissioning.

Uranus was discovered on 13 March, 1781, by William Herschel. The object, which was initially thought to be a comet, turned out to be a new planet outside Saturn's orbit.

It revolves around the Sun in approximately 84 years on an elliptic orbit whose average radius is approximately 2.8 billion kilometres (1.7 billion miles). Unlike other planets, Uranus spins on its side with respect to its orbital plane. Since 1851, more than 10 satellites and 10 rings have been found around it.

Scientists from several research institutes and universities, in addition to the National Astronomical Observatory of Japan, have been involved in the commissioning of the Subaru Telescope.