Want Pluto Back? That Means 100 More Planets in Our Solar System

Added: 2026-05-25

[00:00:00]But the next idea from astronomer Alan Stern has appeal also. Alan said that he wants little Pluto. He's been saying this for years. He wants Pluto to be restored as the ninth planet. And when I say little, I mean Pluto and Eris are much much less massive than our Earth and Moon, which are in turn much less massive than our solar system's gas giant worlds, Jupiter, Saturn, Uranus, and Neptune. If you put Earth on a scale, you'd need about 450 planet Pluto's to balance it out. Still, Pluto has enough mass to have enough self-gravity to pull itself into the shape of a ball. And this idea that planets are the round things is called the geophysical planet definition. If we adopt the geophysical definition and call Pluto a planet, we'll have to use the word planet for many other objects in our solar system. So, in addition to the eight classical planets, we'd be using the word planet for these currently identified dwarf planets, including Pluto.

[00:01:17]And plus, there are many other newly discovered objects out beyond Neptune in the Kuiper Belt, uh believed to be round. They'd all be planets, too.

[00:01:30]And ultimately, our solar system, our neighborhood of space, would have at least several dozen planets, possibly 100 planets, uh according to the geophysical planet definition.