Soon after the discovery of the planet, controversy among astronomers arose. Is Pluto qualified to be a planet? For an object to be a planet it has to meet three requirements defined by the IAU (International Astronomical Union). It needs to be in orbit around the Sun, it needs to have already “cleared the neighborhood” of its orbit, and it needs to have gravitational pull strong enough to pull itself into a sphere. Pluto doesn’t apply to the second rule. “Cleared its neighborhood” basically means that as planets form, they become the dominant gravitational body in their orbit. So when they interact with smaller objects, they consume them or sling them away with their gravity. Pluto’s mass is only 0.07 times the mass of other objects in its orbit. Comparatively, the Earth has 1.7 million times the mass of other objects in its orbit. So any object that does not meet the 2nd rule is considered a dwarf
Soon after the discovery of the planet, controversy among astronomers arose. Is Pluto qualified to be a planet? For an object to be a planet it has to meet three requirements defined by the IAU (International Astronomical Union). It needs to be in orbit around the Sun, it needs to have already “cleared the neighborhood” of its orbit, and it needs to have gravitational pull strong enough to pull itself into a sphere. Pluto doesn’t apply to the second rule. “Cleared its neighborhood” basically means that as planets form, they become the dominant gravitational body in their orbit. So when they interact with smaller objects, they consume them or sling them away with their gravity. Pluto’s mass is only 0.07 times the mass of other objects in its orbit. Comparatively, the Earth has 1.7 million times the mass of other objects in its orbit. So any object that does not meet the 2nd rule is considered a dwarf