Why is pluto is no longer belong in the nine planet?
Pluto resides in a region of the solar system called the Kuiper belt. Astronomers estimate that there are at least 70,000 icy objects, with the same composition as Pluto, that measure 100 km across or more in the Kuiper Belt. In 2005 astronomers discoved an object even larger than Pluto later named Eris. Astronomers decided that they needed to make a final decision on what consituted a planet or they were going to get thousands of them. They settled on three critera for determining planethood. It needs to be in orbit around the Sun – Yes, so maybe Pluto is a planet. It needs to have enough gravity to pull itself into a spherical shape – Pluto…check It needs to have “cleared the neighborhood” of its orbit – Uh oh. Here’s the rule breaker. According to this, Pluto is not a planet. Because Pluto is not massive enough to have absorbed the thousands of other kuiper belt objects it is classified as a dwarf planet, same as Eris.
