Question

Pluto, discovered in 1930, was added as the farthest planet in our solar system. However, in August 2006 the International Astronomical Union downgraded the status of Pluto to that of a dwarf planet. Name three criteria that were used for the reclassification.

Answer 1

1. It is in orbit around the Sun.
2. It has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
3. It has “cleared the neighborhood” around its orbit.