Since it’s downgrade from planet to dwarf planet in 2006, we can’t help but feel a bit sorry for poor Pluto. Seven decades after it’s discovery by Clyde W. Tombaugh, the International Astronomical Union (IAU) decided that the tiny sphere wasn’t a planet after all, throwing school textbooks across the world into disarray.
Despite having its own moons, the IAU claims says that Pluto only meets two of the three requirements to be a planet. Although it orbits around the sun and is big enough to be grounded by its own gravity, Pluto fails to “clear” its orbit, meaning its not the largest gravitional force in its trajectory. Pluto shares its orbit with other objects in the Kuiper Belt, and as a result lost its status as the ninth planet in our solar system.
However, new research from the University of Central Florida might return Pluto to its former glory.
Planetary scientist Philip Metzger, who helmed the project, immersed himself in scientific literature from the past few centuries. He discovered only one publication, dating from 1801, that believed “clearing” should be required for planetary status.
“The IAU definition would say that the fundamental object of planetary science, the planet, is supposed to be a defined on the basis of a concept that nobody uses in their research,” Metzger explained.
“And it would leave out the second-most complex, interesting planet in our solar system.
“We now have a list of well over 100 recent examples of planetary scientists using the word planet in a way that violates the IAU definition, but they are doing it because it’s functionally useful.”
However, Metzger has never been a fan of the IAU definition, describing it as “sloppy.”
When Pluto was declassified 12 years ago, he said: “They didn’t say what they meant by clearing their orbit. If you take that literally, then there are no planets, because no planet clears its orbit.”
Kirby Runyon, who co-authored the study, said that the literature review proved that clearing its orbit was not an historic standard for defining a planet.
“We showed that this is a false historical claim,” Runyon said. “It is therefore fallacious to apply the same reasoning to Pluto.”