Wikijunior:Solar System/Pluto

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Pluto is a dwarf planet that was discovered by the astronomer Clyde W. Tombaugh in Arizona on February 18, 1930.[1]

Pluto twice, a smaller raw and a larger processed image combined, from the Hubble Space Telescope
Pluto twice, a smaller raw and a larger processed image combined, from the Hubble Space Telescope

en:Image:Pluto_symbol.ant.png Pluto Facts:

  • Pluto is a dwarf planet, smaller even than Earth's Moon.
  • Pluto sometimes moves closer to the sun than Neptune.

Contents

[edit] How big is Pluto?

Comparison of the sizes of Pluto, Charon, the Moon and Earth
Comparison of the sizes of Pluto, Charon, the Moon and Earth

Pluto's mass is about 12,500,000,000,000,000,000,000 kilograms.[2] While this may seem large, it's only about 1/500th of the Earth's mass. Pluto is between 2200 and 2400 kilometers across.[3] Its surface area is about 17,950,000 square kilometers (or 1/30th of the Earth's).[4] Its volume is 7,150,000,000 km3 (or 1/150th of the Earth's).[5]

The Solar System

Introduction
Our Solar System
The Sun
Mercury
Venus
Earth
Moon
Mars
Asteroid belt
Jupiter
Saturn
Uranus
Neptune
Pluto
Comets
Kuiper Belt
Oort Cloud
Glossary

[edit] What is its Surface like?

We don't really know for sure what its surface is like. No spacecraft has ever been there, and even the best telescopes can't see any detail. It is certainly very cold, at about -230 °C.[6] The surface is covered with ice.[7] Pluto also has a very thin atmosphere which freezes when Pluto moves further from the Sun.[8]

The image to the left shows Pluto's color.

[edit] What are Pluto's moons like?

To date Pluto has three known moons. The largest is called Charon. Charon is about half as wide as Pluto. Some times Charon and Pluto are considered doubled planets because they are so close to the same size.[9] Its surface is covered in water ice.[10] In Roman mythology, Charon took dead souls across the river Acheron to the land of the dead.[11] Two other moons were discovered in late 2005. They have been named Nix and Hydra.[12]

[edit] How long is a day on Pluto?

One day on Pluto is about 6.487 Earth days long. Like Uranus, Pluto also spins on its side.[13] It is about 6 days to be more precise

[edit] How long is a year on Pluto?

One year on Pluto would be about 90,613 days or 248 years on Earth![14]

[edit] What is it made of?

Scientists believe Pluto is made mostly of rock and ice,[15] but they will not be sure until more research is done. The discovery of Charon helped scientists estimate the density of Pluto. The information collected told them what Pluto was and was not made out of. If Pluto were made out of heavy solids, it would have a very high density. If it were made of gases, it would have a low density. Pluto is somewhere in between, so it is probably made of rock and ice.

[edit] How much would Pluto's gravity pull on me?

If you were on Pluto, gravity would be only 0.06 times as strong as it is on Earth. [16] This means you could do really high jumps—even more than people could on the Moon!

[edit] Who is Pluto named after?

Pluto was named after the Roman god of the underworld. In Roman mythology, he kidnapped Proserpina (Persephone) so he could marry her. This made her mother, the goddess of agriculture, very sad, causing winter. To end winter, Jupiter, his brother, sent Mercury to get her back. Pluto agreed that she could go back, assuming she had not eaten anything from the underworld. However, she had eaten six pomegranate seeds, so Jupiter decided she had to spend six months in the underworld each year. This is the Roman myth of winter. When she goes to the underworld, everything stops growing. When she comes back, her mother is happy again, and life returns. [17]

[edit] Is Pluto a planet?

The organization that names Solar System objects is called the International Astronomical Union (IAU). According to the IAU, Pluto is officially a dwarf planet, which is different than a regular planet. Pluto has been officially classified as a dwarf planet, and the tenth largest object in the solar system since 2006. In the world of astronomy, not everyone agrees.[18] However, most scientists now accept that Pluto isn't a planet.


Next Topic: Comets

[edit] References

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