Pluto: Planet or Dwarf Planet?
Percival Lowell, an American astronomer, discovered Pluto 83 years ago and the tiny, frozen world became the 9th planet of our solar system. In 2005 astronomers spotted an object beyond Pluto's orbit that was actually bigger! Was this our 10th planet? But wait, there were more objects orbiting the sun that were as big as, or bigger than Pluto
