New research suggests that Pluto should be reclassified as a planet

In 2006, the International Astronomical Union, a global group of experts in astronomy, defined a planet that required it to "clear" its orbit or, in other words, the greatest gravitational force of its orbit.

Since Neptune's gravity influences his neighboring planet Pluto and Pluto shares his orbit with frozen gases and objects in the Kuiper belt, it meant that Pluto was off the planet. However, in a new study published online Wednesday in the journal IcarusPhilip Metzger, research scientist in planetary sciences at the University of Florida, said that this standard for the classification of planets was not taken into account in the scientific literature.

Metzger, who is the lead author of the study, reviewed the scientific literature of the last 200 years and found only one publication – from 1802 – that used the rule of orbiting to classify the planets.

He said that moons such as Saturn's Titan and Jupiter's Europa have been commonly called planets by planetary scientists since the time of Galileo.

"The definition of AIU would say that the fundamental object of planetary science, the planet, is supposed to be defined on the basis of a concept that no one uses in its research", said Metzger. "And that would leave out the second most complex and interesting planet in our solar system." "We now have a list of more than 100 recent examples of planetary scientists using the word planet in a way that violates the definition of AIU because they are functionally useful. ", he said." It's a neglected definition, "Metzger said about the definition of IAU. "They did not say what they meant by cleaning their orbit, if you take that literally, then there are no planets, because no planet is in orbit."

The planetary scientist stated that the literature review showed that the true division between planets and other celestial bodies, such as asteroids, occurred in the early 1950s, when Gerard Kuiper published a distinguishing article.

However, even this reason is no longer considered a determining factor if a celestial body is a planet, Metzger said.

The co-author of the study, Kirby Runyon, with Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland, said that the definition of IAU was flawed since the review of the literature has shown that the separation of asteroids from the planets during the development of the 2006 definition of planets.

"We showed that it was a false historical statement," Runyon said. "It is therefore misleading to apply the same reasoning to Pluto," he said. Metzger said the definition of a planet should be based on its intrinsic rather than changing properties, such as the dynamics of a planet's orbit. "The dynamics are not constant, they are constantly changing," Metzger said. "So, they are not the basic description of a body, they are only the occupation of a body at a present time."

Instead, Metzger recommends classifying a planet according to its size sufficient for its gravity to become spherical.

"And it's not just an arbitrary definition," said Metzger.It turns out that it's an important step in the evolution of a global body, because apparently when that happens, it initiates an active geology into the body. "

Pluto, for example, has an underground ocean, a multilayered atmosphere, organic compounds, evidence of ancient lakes and multiple moons, he said.

"It's more vibrant and alive than Mars," Metzger said. "The only planet that has a more complex geology is the Earth."

Explore more:
Scientists defend planet status of Pluto