A space oddity
Pluto was named after the
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Roman God of the Underworld. Venetia Burney, aged 11, came up with the name.
It was discovered on
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February 18, 1930, by Clyde Tombaugh, above, at the Lowell Observatory in Arizona. For the 76 years between Pluto being discovered and the time it was reclassified as a dwarf planet in 2006, it completed under a third of its orbit around the Sun.
Pluto was downgraded from
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“planet” to “dwarf planet” by The International Astronomical Union, who said it did not meet all the criteria for it to be an actual planet.
This led to a slang phrase “to
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Pluto”, meaning to demote or remove something altogether from a prestigious group or list.
The planet is smaller than a
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number of the Solar System’s moons, including our own. It has 66% of the diameter of our moon and 18% of its mass.
Pluto is orbited by five
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moons – Charon, Styx, Nix, Kerberos and Hydra.
The dwarf planet is 30% water.
7 It also has several mountain ranges, light and dark regions and some craters on its surface.
It also has a heartshaped
8 feature, discovered in 2015. Called Tombaugh Regio, it’s named after Pluto’s discoverer and is a large, bright plain on the surface. Pluto’s heart makes its winds blow.
Pluto has an erratic and
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inclined orbit, the reason for which remains a mystery. It can cross Neptune’s orbit and sometimes be closer to the Sun than its bigger neighbour. This was the case between 1979 and 1999. Because it’s so far from the
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sun, Pluto is one of the coldest places in the solar system. It’s surface temperatures are usually around -225°C.
If you lived
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there, it would take 248 Earth years to celebrate your first birthday in Pluto years. And
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if you weighed 100lbs on Earth, you’d weigh just 7lbs on Pluto.
Pluto has only been visited
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by one spacecraft, New Horizons, which flew by on July 14, 2015, taking a series of images so scientists could study the mysterious world further.
The planet occasionally has
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an atmosphere. When closer to the sun, Pluto’s surface ice thaws and forms a thin atmosphere of nitrogen, methane, and carbon monoxide. But when it travels away from the sun this freezes back into its solid state.
Pluto has featured in many
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science fiction novels, TV shows and films, including Doctor Who, Star Trek and Mork & Mindy. It’s also thought Walt Disney named his cartoon dog and pet of Mickey Mouse, Pluto, in 1930 to cash in on the newly discovered planet.