Geology Fun Fact
Myth: Pluto was stripped of planethood because people didn’t like it.
In reality, the reason Pluto got demoted is because the definition of a planet was not set until the International Astronomical Union (IAU) defined it in August 2006. In short, they stated that a planet:
- Orbits the Sun
- Is relatively round
- Has cleared its orbital neighborhood
#3 is the reason Pluto was demoted. Pluto’s moon, Charon is about half the size of Pluto and does not orbit Pluto. Essentially, they orbit the same point in space making it more of a binary system and not a lone planet. So, by definition Pluto is not a lone object orbiting the sun and therefore is not a planet.