NASA chief, Jim Bridenstine, in his recent speech at the FIRST Robotics Event in Oklahoma, declared Pluto to be a planet again, contradicting the decision of the International Astronomical Union (IAU) deeming it as Dwarf planet in 2006.
Cory Reppenhagen, a journalist at 9NEWS, shared a 15-minute video clip on Twitter, where the NASA chief is seen saying: “Just so you know, in my view, Pluto is a planet, and you can write that the NASA administrator declared Pluto a planet once again.”
“I’m sticking by that. It’s the way I learned it, and I’m committed to it,” he added.
“Pluto’s status as a planet has sparked the human imagination for decades. Now is not the time to downgrade Pluto’s status,” Jim Bridenstine said.
The International Astronomical Union had categorized the solar system bodies into three categories — planets, dwarf planets, and small solar system bodies.
IAU stripped Pluto of its planetary status and classified it as a dwarf planet on grounds that it did not fulfill the requirements to be a planet as per the definition of the term by IAU.
The requirements to be defined as a planet, as stated by IAU, said that a celestial body needs to “clear” its own orbit. This means that the body needs to be the largest gravitational force in its own orbit.
However, Pluto did not fulfill this criterion as Kuiper belt objects and frozen gases share its orbit. Besides, the gravitational force of its neighbouring planet, Neptune, also affected Pluto’s orbit.
Moreover, icy Pluto is not bigger than a lot of other objects that currently exist in the Galaxy. If Pluto continues as a planet, three more with similar features – Pluto’s moon, Charon recognized as a twin planet, Ceres and Eris, have to be added to the solar system which would increase the number of planets in the Sun’s orbit from nine to 12.
Therefore, after much debate, Pluto was deprived of its planet status. The then president of planetary systems science Prof Iwan Williams said, “By the end of the decade, we would have had 100 planets, and I think people would have said ‘my goodness, what a mess they made back in 2006’.”
However, even after more than a decade, the debate regarding whether Pluto is a planet or not continues as the decision for it being classified not a planet was taken by just 5% of the total astronomers around the world.
In 2018, a planetary scientist from the University of Central Florida, Philip Metzger, argued that Pluto qualifies for the title. He argued that planets should be classified based not on their size, but if they are big enough to create a gravity field that allows them to be spherical.