An Introduction to Dwarf Planets

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The International Astronomical Union delivers useful and helpful information about the local solar system. There is a difference between a dwarf planet and a planet. Planets make clear paths around the sun, while dwarf planets only orbit in zones around the sun, and other objects can cross their path. Researchers believe that there are more than a hundred dwarf planets waiting to be recognized, discovered, named and studied. The first five dwarf planets that have been recognized are Ceres, Pluto, Eris, Makemake and Haumea.

Dwarf planets are not moons as some people think they are. A dwarf planet is just a celestial body that makes an orbit around the sun, but has not cleared the neighborhood around the orbit like a regular planet does. Dwarf planets gain enough mass to almost take on a round shape. Some of the dwarf planets have more gravitational pull than the Earth. Their size is smaller than the planet Mercury. Dwarf planets are really so small that about 30,000 of them could fit inside the Earth.

It was in 2006 that Pluto was demoted to a dwarf planet, after all this time being known as the smallest planet. Eris is the largest of the dwarf planets. Eris was discovered in 2003 and it is just a little larger than Pluto. Eris has one moon that is known by the name of Dysnomia. Pluto was discovered in 1930 and was part of the eight regular planets. Pluto has five moons; two of them are so newly discovered that they have not been given names yet. Charon, Nix and Hydra are Pluto's moons that have been named. Haumea is a dwarf planet that was discovered in 2003, and it has two moons called Hi'iaka and Namaka. Ceres was discovered in 1801 as a regular planet, but was later classified as an asteroid. Ceres became known as a dwarf planet in 2006. Ceres has no moons that have been discovered yet. Makemake is the dwarf planet discovered in 2005 and it also has no moons.

This solar system is a complicated one, and it becomes more confusing to those who were taught that there were only nine planets. New discoveries are being made. Although it may be complicated, it is a really exciting and educational experience to learn about the new dwarf planets and their moons and other things in the solar system that share their orbits. In fact, for three-quarters of a century all school kids were taught that there were nine planets. Now things in this solar system are bringing about new changes to the world. Dwarf planets were at one time called subplanets or planetoids. In the local solar system, there are three distinct categories: planets, dwarf planets and all other objects.

Comets and asteroids also orbit the sun, but there is a difference, as comets are made up of frozen ammonia, methane, water and rock material. Sometimes comets are called dirty snowballs. An asteroid is composed of rock or metal.

More about this author: Shannon Farlouis

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