Why are Dwarf Planets Not Planets?

Such as Pluto, and Eris

Our Theory

Pluto was once a huge planet but then an asteroid came and ba-boom! About 2/3 of Pluto was broken off and had to joined the Kuiper Belt. We also think that happened to the other dwarf planets around Pluto.

Qualities Needed to be a Planet

  • Has to orbit Sun
  • Has to be mostly round
  • Has to be able to clear other objects in its way

Facts About Pluto and other Dwarf Planets

  • Pluto met 2 of these needs being mostly round and orbiting the sun but it wasn't able to clear different space objects out of its way. Making it not able to be a planet anymore.
  • Clyde Tombaugh discovered Pluto on February 18, 1930 on search of Planet X.(Planet X was a planet that people thought was beyond Neptune.
  • Heat from the sun melts Pluto's ice into gas then since Pluto is so cold the gas freezes back into ice.
  • Pluto's atmosphere forms only when it orbits the Sun.
  • Venetia Phair, an eleven year old, was the first person to suggest the name Pluto.
  • Pluto's largest moon is about half it's size. That moon is Charon.
  • Some rejected names for Pluto are: Constance, Cronus, Lowell, Minerva, Percival, and Zeus.
  • On Pluto a 100 pound person would equal 7 pounds.
  • Pluto has 5 moons that orbit around it Charon, Nix, Hydra, Styx, and Kerberos.
  • 3.7 billion miles away from Pluto is the Sun.
  • On Pluto 6 of our Earth days are just 1 day for Pluto.

Pluto and Eris

  • In 2005 the Dwarf Planet named Eris was founded by 3 scientists Michael E. Brown, David L. Rabinowitz, and Chad Trujillo.
  • In 1978 Pluto's main moon, Charon, was founded. Part of the reason Charon surface is so rocky is because it is part of Pluto. At least that's what we think.
  • Pluto at least had 76 years to be a planet but Eris had 1 year where it was being determined if it was going to be a planet or a Dwarf Planet.
  • By 1987 Pluto had moved into a position that only occurs twice in its 248- year orbit and scientific instruments had improved.
  • Eris is considered the 10 planet.
  • Many scientist think that Pluto has a rocky core, and Aliyah thinks that is why it broke off so easily.
  • Pluto's orbit intercepts with Neptune's orbit because it goes diagonally across every other planet's orbits.
  • Pluto diameter is 1,440 miles across.
Big image


In the end we learned that many dwarf planets are that because they weren't able to meet the 3 qualities needed to be a planet. Also that many dwarf planets were put out just because they were to small and had big neighbors. But there are many other dwarf planets in the Kuiper Belt that are yet to be discovered. Also we have hope with many other people who love Dwarf Planets that Pluto and maybe some of the other Dwarf Planets will be reinstated someday.
Poor Pluto