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Pluto: 10 Interesting Facts and Resources

Pluto is not a planet any more, but just a “dwarf planet” in our Solar System with some interesting qualities. Pluto was discovered in 1930 after much difficulty because of its small size. It also moves extremely slow, so that added to the time it took to be noticed; it takes 248 years to complete orbit around the Sun. Light from the Sun takes approximately five hours to reach Pluto, to compare, it takes eight minutes to reach the Earth. Here are ten things you may or may not know about Pluto, all thought-provoking facts for conversation.

Average Temperature

Pluto’s average temperature is a mere 44 degrees above absolute zero, the dwarf planet has an atmosphere. It is not an atmosphere as we are accustomed to or would ever wish to even live near, but it is in fact an atmosphere. Astronomers first discovered it in 1985 when they watched as Pluto passed in front of a star and they saw a dimming of the atmosphere and then Pluto blocked visibility of the star entirely. They could then determine that Pluto is surrounded by nitrogen, carbon dioxideand methane.


There are three moons, named Charon, Nix and Hydra. Charon is the largest at about half the mass of Pluto. Nix and Hydra were discovered in 2005 and named in 2006. These two moons are considerably smaller so they took a long time to see.

Is Pluto a Planet?

Although Pluto orbits the Sun and its round, it is not a planet. That’s because Pluto hasn’t cleared out its orbit of material. This was the reason that the International Astronomical Union chose to demote it from planet to dwarf planet in 2006. Just to give you an idea, if you added up the mass of all the other objects in Pluto’s orbit, Pluto’s mass would only be a tiny fraction of that total. In fact, it would only be 0.07 times as massive as everything else. For comparison, if you did the same thing with all the other material in the Earth’s orbit, our planet would be 1.5 million times as massive.

Before being ripped of its title as a planet, astronomers considered categorizing it as a binary planet system; then as a binary dwarf planet system, thinking that would help recover its lost brilliance. Pluto and Charon orbit the same point in space that is above the surface as opposed to the Earth and the Moon where the common point of orbit is inside the Earth.

Where did Pluto get its name?

Pluto is named after the Roman god of the underworld, not a dog that Disney created; and Charon is the ferryman who carries souls across the Styx river. The first name for this dwarf planet was “Planet X” before explorers decided to come up with something more stable. An 11 year old girl in Oxford, England suggested the name Pluto because she thought it was fitting for such a dim, cold realm.

Distance From Earth

Every couple hundred years Pluto is closer than Neptune. Usually it is the opposite, reaching as far as forty nine times the distance from the Earth to the Sun, however the elliptical orbit makes it come much closer at times and then it is also orbiting in the same space as Neptune.


The dwarf planet is the smallest out there, it is smaller than any other planets and seven moons. The mass of Pluto is less than 0.24% of the mass of the Earth. It is only 1485 miles in diameter. There is another dwarf planet named Eris which is bigger than Pluto.


Pluto would be considered a comet if it were any closer to the Sun. This is not a reason why it is no longer classified as a planet, but it would not last long if the distance between Pluto and the Sun were any less because it is made of rock and ice. This is comparable to other comets in the Solar System. If it were possible to bring these two closer, Pluto would become a remarkable comet with a tail and loss mass due to the solar wind attacking its structure.


Astronomers have recently discovered that many objects in the Solar System have ice geysers, including Saturn’s moon Enceladus. They have proof that geysers on Charon are dispersing water crystals and ammonia hydrates across the surface.

Traveling To Pluto

In 2005, NASA’s New Horizons spacecraft launched with Pluto as the destination. They expect to arrive there in 2015 to take images of Pluto’s surface and its moons to answer questions that are a hundred years old.

There are many other interesting things to learn about the planets in our Solar System and the qualities they each possess. Take some time out to look up and appreciate the beauty of the skies and the internet can help with some detailed pictures and other information to feed your mind.