Should Pluto be Considered a Planet… Again?

Samara Mathew (9) | STAFF REPORTER

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; these are the celestial bodies that children of this day and age have familiarized as the official eight planets of our solar system. However, before 2006, there were nine celestial bodies considered to be planets in our solar system, with the planet farthest from the sun being Pluto. Since the International Astronomical Union (the IAU) made the decision to reconsider Pluto as a planet, and then officially rebranded Pluto as a dwarf planet, the debate over whether Pluto should be a planet has been reopened numerous times. There are strong arguments coming from both sides of the table, with scientists defending and countering Pluto’s status as a planet. What do you think? Should Pluto be considered as a planet again, or should it remain a dwarf planet?

Unsettlement surrounding Pluto’s status as one of the planets in our solar system (which it has held since 1930) began in 2005 when astronomers discovered Eris; an icy plutoid located fifteen billion kilometers away from the sun at its farthest orbital point. Eris was a small celestial body with characteristics that differed from the other planets, and this made astronomers worried about finding many more similar planets in the outermost regions of our solar system. At the time of Eris’ discovery, planets were defined as any celestial body that orbited around a star. So, to avoid this dilemma, the International Astronomical Union came up with a new official definition for a planet. They defined a “planet” as a a celestial body that independently orbits the sun (is not a moon or satellite of another object), has enough mass to be roughly rounded by its own gravitational pull, and has cleared its neighbourhood of most other orbiting spatial objects. Pluto, whose gravity is affected by Neptune, has a more oval-shaped orbit than the other planets, shares an orbit with many objects from the icy Kuiper Belt, and was originally thought to be smaller than Eris, was therefore deprived of its status as a planet and categorized as a dwarf planet.

A dwarf planet has similar features as a planet but has not cleared its orbital path, which is why many people were satisfied by the demotion of Pluto. However, not everyone agrees with this, including NASA chief Jim Bridenstine. During his speech at the Washington D.C. International Astronautical Congress in October 2019, Bridenstine said “I am here to tell you, as the NASA Administrator, I believe that Pluto should be a planet”. Bridenstine believes that Pluto’s moons, complex organic compounds, and buried ocean contribute to regaining Pluto’s status as a planet back – and he isn’t alone in his claims. Many scientists and astronomers also disagree with this classification, especially after new evidence on Pluto was revealed by NASA’s New Horizons interplanetary space probe in 2015. While flying by Pluto and one of its moons, Charon, the space probe captured images of mountain ranges as high as 3,500 metres called Plutonian montes, snakeskin looking terrain, and frozen plains located in Tombaugh Regio (a light-coloured, heart shaped region). After reviewing this new information, many members of the New Horizons space probe team have brought forth arguments against the International Astronomical Union’s definition of a planet, in hopes of reinstating Pluto’s planethood. The size of the dwarf planet Eris – which was once thought to the largest body beyond Neptune’s orbit and bigger than Pluto – was also recalculated and revealed that Eris is actually slightly smaller than Pluto.

As the debate surrounding Pluto’s planetary status continues, new data continues to sprawl from both sides of the house. For now, Pluto remains classified as a dwarf planet. But as we continue to delve further into outer space, and explore the wonderful mysteries of our universe, new evidence come forth. Who knows? Perhaps Pluto will eventually regain its status as a fully-fledged planet, and your children will grow up familiarizing themselves with nine – instead of eight – official planets.