Pluto’s status as the ninth planet of the solar system came into question when the International Astronomical Union (IAU) demoted it and included it in the category of dwarf planet. The reason was that Pluto did not meet the official definition of a planet as described by the IAU in 2006.
According to the definition, a celestial body which circles the sun without being some other object’s satellite is round or nearly round and has cleared its neighborhood of most other orbiting bodies is a planet. As Pluto shared the Kuiper Belt with lots of other big objects, it did not meet the third criterion. This led to Pluto’s rebranding as a dwarf planet.
Well, a new study conducted by Philip Metzger, a planetary scientist in the University of Central Florida, and his team claim that Pluto should be reclassified as a planet.
The research team claims that the rationale behind downgrading Plutos’ planet status wasn’t even valid. For the purpose of the study, the researchers scoured scientific literature from the past 200 years and found that only one study, from the early 19th century, employed the orbit-clearing standard the IAU used to downgrade Pluto.
“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 said, reported Space.com.
Metzger pointed out that standard used to classify planets changed in the 1950s after astronomer Gerard Kuiper said what really determines what is and what isn’t a planet is how a celestial body is formed. He described the IAU’s definition of a planet as sloppy.
The research team claims that a planet should be classified based on if it’s big enough that its gravity allows it to become a spherical shape.
“It turns out this is an important milestone in the evolution of a planetary body, because apparently when it happens, it initiates active geology in the body,” Metzger said.
The research study has been published in the scientific journal Icarus.