The new research document published by the University of Central Florida in Orlando declared the reason due to which Pluto lost its planet status is not acceptable.
A global group of astronomy experts, the International Astronomical Union ascertained a definition of a planet that made for the planets to “clear” its orbit or be the largest gravitational force in its orbit.
As Neptune’s gravity affects its adjacent planet Pluto, and Pluto shares its orbit with objects in the Kuiper belt and frozen gases, which meant Pluto was out of planet league.
A new study issued online on Wednesday in the journal Icarus, UCF planetary researcher Philip Metzger claimed that this criterion for classifying planets are however not valid according to the research literature.
Since the time of Galileo Jupiter’s Europa and Saturn’s Titan have been routinely called planet by the scientists, said Metzger.
He further stated, “The IAU definition would say that the fundamental object of planetary science, the planet, is supposed to be a defined based on a concept that nobody uses in their research. And it would leave out the second-most complex, interesting planet in our solar system. We now have a list of well over 100 recent examples of planetary scientists using the word planet in a way that violates the IAU definition, but they are doing it because it’s functionally useful.”
Metzger claimed IAU’s definition as “sloppy definition”. “They didn’t say what they meant by clearing their orbit. If you take that literally, then there are no planets, because no planet clears its orbit.”
The researcher further clarified that the literature revealed that the actual differentiation between other celestial bodies and planets occurred in the early 1950s when Gerard Kuiper issued a paper differentiating based on their formation.
Study co-author Kirby Runyon in coalition with Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, claimed IAU’s definition specious as the literature review hinted that clearing is not a valid standard to be used for distinguishing asteroids from planets like the IAU claimed while designing the 2006 definition of planets.
Runyon said, “We showed that this is a false historical claim. It is therefore fallacious to apply the same reasoning to Pluto”. Metzger, however, defined planet based on its intrinsic properties, instead of the dynamics of the planet’s orbit. “Dynamics are not constant, they are constantly changing. So, they are not the fundamental description of a body, they are just the occupation of a body at a current era,” said Metzger.
He instead recommends classifying a planet only if it is large enough that its gravity allows it to become spherical in shape.
Metzger said, “And that’s not just an arbitrary definition. 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.”
Pluto, for instance, has an underground ocean, a multilayer atmosphere, organic compounds, evidence of ancient lakes and multiple moons, he said.
“It’s more dynamic and alive than Mars,” Metzger said. “The only planet that has more complex geology is the Earth.”