Mary Bowerman

USA TODAY Network

A group of NASA scientists has proposed a new definition of what constitutes as a planet, possibly opening the door for Pluto to return to its former status.

First discovered and classified as a planet in 1930, Pluto had its planetary status dragged out from under its cosmic feet in 2006 because there appeared to be other objects like Pluto beyond the eighth planet (Neptune.) Pluto was thus demoted to a “dwarf planet.”

The demotion of the planet is quite simply “bulls***,” Alan Stern, principal investigator of NASA’s New Horizons mission to Pluto told Business Insider in 2015.

And two years later, Stern and his colleagues are not backing down from that belief, Gizmodo reports. In a proposal sent to the International Astronomical Union (IAU) for approval, the team suggests that a new definition of a planet, that is more in line with “scientific classification and peoples’ intuition.”

“In the mind of the public, the word 'planet' carries a significance lacking in other words used to describe planetary bodies,” the proposal states. “In the decade following the supposed 'demotion' of Pluto by the International Astronomical Union, many members of the public, in our experience, assume that alleged 'non-planets' cease to be interesting enough to warrant scientific exploration.”

Wait, what? Pluto a planet again?

The scientists suggest planets should constitute as “round objects in space that are smaller than stars,” thus excluding white dwarfs, neutron stars, and black holes from the planetary status.

"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," the proposal elaborates, noting that the Earth's moon would constitute as a planet under the new definition.

Stern and his colleagues note that the IAU’s definition of a planet is too narrow and recognizes planets only as objects that orbit our sun and "requires zone clearing, which no planet in our solar system can satisfy since new small bodies are constantly injected into planet-crossing orbits."

While this isn’t the first time that researchers have spoken out against Pluto's demotion, the proposal forces the International Astronomical Union to make a decision.

Stay tuned, you may need to relearn that there are nine planets in our solar system.

Follow Mary Bowerman on Twitter: @MaryBowerman