Why Pluto is not a Planet?
Earlier, Pluto was considered as the ninth planet in our solar system. It was first discovered by American astronomer Clyde Tombaugh in 1930. It was on the list of planets until 2006, when the definition of a planet changed, it didn’t match with Pluto’s features. Thus, Pluto lost its position as a planet. It comes under the category of dwarf planets and plutoids. So, now we have only 8 planets in our solar system.
According to International Astronomical Union, a planet should have the following criteria:
- A planet must be round
- It must orbit the sun.
- It must have a clear space around its orbit without intersecting any other objects/planets.
Even though Pluto fits to the first two rules, the third rule doesn’t match with it. It has not ‘cleared the neighborhood’. It rotates the sun in an ellipse or oval shaped path, unlike the circular path like planets. Because of this orbit structure, it intersects with Neptune’s orbit. This is why Pluto is no longer considered a planet. Instead, it has been given a new position as dwarf planet. Dwarf planets are actually celestial bodies that are round orbiting the sun but do not fit into the third rule. So far, there are four dwarf planets discovered in our solar system. They are Pluto, Eris, Makemake, and Haumea.
Some interesting facts about Pluto.
- The size of Pluto is similar to the size of our Moon.
- It takes 248 Earth years for Pluto to orbit around the sun.
- Pluto was named after the Roman god of the underworld, Pluto.
- Pluto has 4 moons – Charon, Hydra, P4, and Nix.
- The orbit of Pluto is not only in ellipse shape but is tilted having an unusual orbit.