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Friday, 17 March 2017


Pluto is a dwarf planet orbiting the Sun, with about a sixth of the mass of the Moon and a third of its volume.


Pluto was photographed for the first time on March 19, 1915, 15 years before it was officially discovered by Clyde Tombaugh.

24-year old astronomer Clyde Tombaugh discovered Pluto while studying photographs taken at the Lowell Observatory in January 1930. News of the discovery was telegraphed to the Harvard College Observatory on March 13, 1930.

Clyde Tombaugh, discoverer of Pluto here shown with his homemade 9-inch telescope.

The name Pluto, after the god of the underworld, was proposed by Venetia Burney (1918–2009), a then eleven-year-old schoolgirl in Oxford, England, who was interested in classical mythology. She suggested it in a conversation with her grandfather Falconer Madan, former Science master at Eton, who had come up with the name for the two moons of Mars, Deimos and Phobos half a century earlier.

Pluto was originally considered to be the ninth planet from the Sun, but the International Astronomical Union came up with a new definition for planets in 2006 that excluded Pluto after many other similar icy objects were found, including Chiron and Eris.

Venetia, the young girl who suggested the name in 1930, lived to see the planet demoted to "dwarf planet" status in 2006.

In 2009, the US State of Illinois voted to continue regarding Pluto as a planet. This was mainly because Clyde Tombaugh was from Illinois.

A spacecraft visited Pluto and its moons for the first time on July 14, 2015. The New Horizons probe performed a flyby and took detailed measurements and images.

Pluto in near-true color, imaged by New Horizons
Clyde Tombaugh, the astronomer who discovered Pluto, had some of his ashes placed aboard the New Horizons space probe.


Like other Kuiper belt objects, which are generally outside Neptune's orbit, Pluto is primarily rock and ice.

The plains on Pluto's surface are composed of more than 98 percent nitrogen ice, with traces of methane and carbon monoxide.

The mountains are made of water ice.

Pluto is one of the most contrastive bodies in the Solar System, with colors varying between charcoal black, dark orange and white.

High-resolution image of Pluto in enhanced color to bring out differences in surface composition


Pluto has an elongated and highly inclined orbit that takes it from 49 astronomical units (7.4 billion km) away from the Sun down to 30, closer than Neptune.

Pluto last moved inside the orbit of Neptune in 1979. Mathematical calculations suggest that it was on July 11, 1735 when Pluto previously moved inside the orbit of Neptune.

Pluto never made a full orbit around the sun from the time it was discovered to when it was declassified as a planet. It won't complete a full orbit until March 23, 2178.


On June 22, 1978, the largest known moon of Pluto was discovered by James W Christy of the US Naval Observatory in Washington DC. He named it Charon, after the boatman of Greek mythology who ferried people’s souls to Hades, which was ruled by the god Pluto.

Charon, taken by New Horizons late on 13 July 2015. 

Charon is about half as wide as Pluto.

Pluto has five known moons: Charon, Styx, Nix, Kerberos, and Hydra..


A round trip to Pluto would be 7 billion billion miles.

Pluto is about the same area as Russia.

The mass of Pluto is less than one quarter of one per cent of that of Earth.

Light from the Sun takes about 5.5 hours to reach Pluto at its average distance.

The sky is so dark on Pluto that a person would be able to see stars during the day.

It is believed Walt Disney’s cartoon dog Pluto was named after the planet. He was created in 1930, just after Pluto was discovered.

Source Daily Express

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