All About Pluto

Pluto was named by an 11 year old English schoolgirl named Venetia Burney. It was named after the Roman God of the underworld and until 2006 it was considered the 9th planet in the solar system.

It was discovered by 24 year old American astronomer Clyde Tombaugh at the Lowell Observatory on February 18th 1930.

By comparing photographic plates taken over separate nights, Tombaugh spotted that one point of light had moved. On closer inspection it was found to be the elusive ‘Planet X' that had been predicted for many years.

Pluto is a tiny little world; it is smaller than our Moon. It has a brownish yellow colour. But to see it you need a very large telescope indeed.

It is so far away, on average 5 trillion km from the Sun, that even the best images show nothing of the planet.

It goes around the sun once in 250 Earth years in a very elliptical orbit which sometimes brings it in closer than Neptune.

In 1978 it was discovered that Pluto had a tiny Moon Charon and then in 2005 two more satellites were discovered Nix and Hydra.

So why is Pluto no longer a Planet?

In 2006 the international astronomical union drew a series of rules that determined what a planet is and Pluto simply did not qualify; in fact there are more deserving bodies in the solar system.

A planet must be in orbit around the Sun. A planet must be big enough to pull itself into a roundish shape. And a Planet must have cleared its orbit of other bodies.

Pluto is now considered to be just a large member of the Kuiper belt, a band of space debris left over from the formation of the solar system.

These ‘minor planets' are now known as ‘Dwarf planets'.

NASA launched the new horizons mission to Pluto in 2006.

It will arrive in 2015 carrying with it, the Ashes of its discoverer Clyde Tombaugh.