Sixth Grade
Worksheets
Whatever Happened to Pluto? Dr. Mike E. Brown, The Planet Hunter
Once upon a time our solar system contained nine planets. It consisted of the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. In 2006 Pluto was demoted to "dwarf planet" status.
One of the people responsible for Pluto's demotion was Dr. Mike E. Brown. He is presently a professor of planetary astronomy at the California Institute of Technology (Caltech). Brown is well known for his discoveries of objects at the edges of our solar system.
Astronomers call this area "trans-Neptune," which means any area in space beyond the planet Neptune. This trans-Neptunian area has been divided into three sections. They are called the Kuiper (pronounced KY per) belt, the scattered disk, and the Oort cloud. Objects found floating in this part of space are called trans-Neptunian objects, or TNOs.
