Pluto Demoted Day - August 24
Sat, Aug 24, 2024

Pluto Demoted Day

Pluto Demoted Day is celebrated mainly by the scientific community on August 24th each year. This holiday is dedicated to the important astronomical fact that Pluto is not considered a classical planet, but instead is classified as a dwarf planet. This change in classification was the result of current space research.


On August 24th, 2006, the International Astronomical Union (IAU) announced that Pluto did not meet all the requirements for being classified as a classical planet. The IAU established criteria for a celestial body to be considered a planet, including that it orbits around the Sun, has enough mass to form into a sphere, and does not orbit as a satellite of another celestial body. Pluto was found to not fit these criteria and was reclassified as a dwarf planet.

Interesting facts

  • Pluto was discovered in 1930 by Clyde Tombaugh, an employee of Lowell Observatory.
  • The name “Pluto” was suggested by an 11-year-old schoolgirl named Venetia Burney who was interested in myths and thought the name suited the dark icy world.
  • Pluto is also known as the 134340th object in the catalog of minor planets.
  • The term “to pluto” has been coined meaning to demote or reclassify.

How to take part

  • Learn more about space exploration and the classification of celestial bodies.
  • Visit an observatory or stargaze with friends and family.
  • Share information about Pluto Demoted Day on social media using the hashtag #PlutoDemotedDay.

When is Pluto Demoted Day celebrated in 2024?

Pluto Demoted Day is observed on August 24 each year.


Weekday Month Day Year
Saturday August 24 2024
Sunday August 24 2025
Monday August 24 2026