Pluto is a dwarf planet. A dwarf planet travels around, or orbits, the sun just like other planets. But it is much smaller. Clyde Tombaugh discovered Pluto in 1930. He was an astronomer from the United States. An astronomer is a scientist who studies stars and other objects in space. Venetia Burney named Pluto that same year. She was an 11-year-old girl from England. Pluto is not very big. It is only half as wide as the United States. Pluto is smaller than Earth's moon. This dwarf planet takes 248 Earth years to go around the sun. If you lived...