Pluto was long considered our solar system’s ninth planet. Although small, it orbits the sun and has the spherical shape required to be considered a planet.

But today marks 13 years since Pluto received a harsh drop in status — officially dubbed Pluto Demotion Day.

Pluto was relegated in 2006 when the International Astronomical Union (IAU) created a new definition for planets and decided Pluto did not fit the bill.