Pluto: No Longer a Planet

Once known as the ninth planet of the solar system, Pluto is now the second-largest dwarf planet. Composed primarily of ice and rock, Pluto took part of our Solar System for 76 years. It was discovered on January 23, 1930 by Clyde Tombaugh. Tombaugh was an American astronomer who worked at the Lowell Obeservatory. Tombaugh had been working on a project when he came across a moving object in photographs he had taken of the celestial sky. After observing a lower quality picture taken of the mysterious object, it was confirmed that a new planet had been discovered. For many years Pluto was known as the farthest planet from the sun. Charon, Pluto's largest moon, is half the size of Pluto. There are two more moons named Nix and Hydra. They were discovered in 2005.

Though it was discovered by Clyde Tombaugh, the right to name the new planet belonged to the Lowell Observatory. Clyde told the director of the observatory to quickly suggest a name for the planet before someone else got to it. "Pluto" was suggested by an eleven-year-old girl named Venetia Burney from Oxford, England. Burney mentioned the name to her grandfather who later sent on the suggestion to Herbert Turner. It was then that the name was suggested to colleagues in America. The new found planet was officially named "Pluto" on March 24, 1930 and announced on May 1, 1930. Venetia received five pounds as a reward for coming up with the name.

For decades Pluto was considered to be the ninth planet of the solar system. It wasn't until 2006 that people started to speculate that Pluto wasn't in fact a "planet". The debate began when the International Astronomical Union created an official definition for the word "planet". Many believe that there isn't one specific definition of a planet. It was always known when a planet was a planet. In fact, astronomers aren't even sure how to define a "planet". However, they have been able to define a "dwarf planet" which is a celestial body within the Solar System. It has to satisfy these four conditions. It can't be a satellite, hasn't cleared the neighborhood around its orbit, is in orbit around the sun and finally has sufficient mass for its self gravity to overcome rigid body forces. This term of dwarf planet was adopted in 2006. Pluto fell under the category of dwarf planet because it met the four conditions of being a dwarf planet.

...