Pluto

Pluto is the nineth 'planet' from The Sun. However, Pluto is currently classed as a 'Dwarf Planet', as it is believed to be much smaller than the other eight planets and the moons. Pluto takes 247.9 Earth years to orbit The Sun, and travels at an approximate speed of 10,623 mph. Despite it's size, it still has four moons orbiting it.

Discovery
Pluto was discovered by Clyde W. Tombaugh in 1930﻿. Calculations concluded that there was a planet orbiting the sun beyond Neptune. Not knowing that this was actually an error, he performed a detailed analysis of the sky. Maybe it was just making an error at the right time- but he found Pluto. However, this was not the planet Clyde was looking for. That planet has never been found, and it is unlikely that it ever will be.

History of Pluto's Classification
In the past, due to the lack of scientific knowledge, we believed that Pluto was the biggest planet in the Solar System. But on the 24th of August 2006, scientists discovered with the use of new technology, Pluto was actually smaller than the other eight planets and their moons. It was re-classified as a 'dwarf planet'. However, as we learn more and more about Pluto, some people are starting to believe that it should infact be a proper planet. This appeal became stronger on the 20th July 2011, when a fourth moon was discovered orbiting Pluto.