Pluto, which was discovered in the year 1930, was the ninth planet in the solar system for over 75 years. In 2006, however, Pluto was reclassified as a dwarf planet by the International Astronomical Union (IAU).
As Space reported at the time, the vote to strip Pluto of its planet status was not without controversy. Now, more than a decade later, scientists are working on a plan that, if approved, could bring Pluto back into the planet category, according to USA Today.
Per USA Today, a team of NASA scientists recently sent a proposal to the IAU, in which it is argued that Pluto, and many other objects in space, should fall under the planet umbrella. The team is led by Alan Stern, who, as USA Today describes, has been critical of Pluto’s demotion to dwarf planet status in the past. Stern was also principal investigator of the New Horizons Pluto Mission, according to USA Today.
— The New Science (@NewScienceWrld) February 21, 2017
New Horizons arrived at Pluto in the summer of 2015 after more than nine years of traveling through space, according to the New York Times. In November of 2016, the Inquisitr reported that Pluto might be home to a slushy, subsurface ocean. The Inquisitr also later reported that NASA had compiled images collected by New Horizons to create a colorful video that simulated a landing on the dwarf planet. New Horizons has now moved beyond Pluto, and its next big stop is slated to be the mysterious Kuiper Belt object 2014 MU69, according to Space.
In the proposal, Stern and his team argue against the IAU’s current definition of a planet, calling it “technically flawed.” The proposal argues that one of the issues with the definition is the fact that it only covers planets that orbit the Sun in our solar system, excluding objects that are circling “other stars” and “rogue planets” that are “orbiting freely in the galaxy.” Other problems with the current definition are laid out by Stern and his team in the proposal as well.
“[I]t requires zone clearing, which no planet in our solar system can satisfy since new small bodies are constantly injected into planet-crossing orbits, like NEOs near Earth. Finally, and most severely, by requiring zone clearing the mathematics of the definition are distance-dependent, requiring progressively larger objects in each successive zone. For example, even an Earth sized object in the Kuiper Belt would not clear its zone.”
Stern and his team also present a new definition of what a planet should be. If it were to be adopted, it would essentially take what is now a very narrow definition of a planet and make it very broad.
“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 also offers a simpler definition, saying that “round objects in space that are smaller than stars” might be a sufficient way to describe it. According to the proposal, the new definition, if it were to be adopted, would create 110 new planets, including Pluto.
Per the proposal, the Earth’s moon would also become a planet under the proposed definition. The proposal also argues that the dwarf planet Ceres, the largest object in the asteroid belt, and Charon, the largest of Pluto’s five moons, should be classified as “full-fledged planets” as well.
After Charon, the names of Pluto’s four other moons are Styx, Nix, Kerberos, and Hydra. Pluto takes a whopping 248 years to complete a single orbit of the Sun, according to Universe Today.
— NASA (@NASA) February 18, 2017
On February 18th, it marked 87 years since the day Pluto was discovered by Clyde Tombaugh, according to Science Magazine. As Gizmodo describes, it will ultimately be up to the IAU to give the thumbs up or thumbs down as to whether or not the new definition should be adapted, so far the time being, Pluto remains a dwarf planet.
What do you think? Would you be excited to see Pluto once again become the smallest and most distant planet in the solar system, as it was for so many years, or should it remain among the dwarf planets with Ceres, Eris, MakeMake, and Haumea?
[Featured Image by Vadim Sadovski/Shutterstock]