08/24/2026
On this day 20 years ago, August 24th 2006, Pluto was reclassified as a dwarf planet following the discovery of other similar bodies that shared similar orbital and mass properties.
These days, we say a planet is classified via the following criteria:
1. The Sun is the center of its orbit ✅
2. Enough gravity to form a roughly spherical shape ✅
3. Enough gravity to clear its orbit of other objects ❌
While Pluto meets the first two criteria just fine, it does not have enough mass to collect the debris around it, or fling that debris elsewhere through the solar system.
Think of vacuum cleaners: the major 8 planets are Dysons, powerful suction grabbing every chunk of dirt and dust they gets close to on the first try. Pluto, on the other hand, is a handheld dirt devil that has to run over the same spot multiple times to clean the rug.
While I love Pluto (I mean come on, outside Saturn, I think it LOOKS the coolest), these criteria are valid and internationally agreed upon standards. It's still a planet, and always will be.
But it's a dwarf planet.
