Is Pluto a Planet? This New Definition Might Say So

Solar system displays are one of the most essential and memorable projects for any elementary school student, but things changed in 2006, when Pluto was downgraded to a dwarf planet and students were no longer required to include the ninth planet. Pluto's recognition as a planet has been up for debate since it was discovered in 1930, and now, the entire definition of "planet" is in question.

At the Lunar and Planetary Science Conference in The Woodlands, TX, Kirby Runyon of Johns Hopkins University presented a new understanding of what it takes to qualify as a planet and it's incredibly more inclusive. According to Runyon, a planet is, "a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters."

Runyon's definition of a planet would not only qualify Pluto as a planet again, but it also deems more than 100 other objects in our solar system as planets, including Earth's moon. His proposal eradicates the main element of the International Astronomical Union's definition of a planet, which is what initially demoted Pluto to a dwarf planet in 2006. It stated that planets are round objects that orbit our sun and are big enough to clear the neighborhood around its orbit.

His new definition is reopening the controversial discussion about our solar system, and we're looking forward to seeing how this unfolds.