Astronomers say Pluto should be a planet based on new research

More than a decade after its reduction, the debate over whether Pluto is a planet has been revived by a new study.

A new study from the University of Central Florida in Orlando claims that the reason why Pluto lost its planet status is "invalid".

In 2006, the International Astronomical Union, a global group of astronomical experts, defined the planet as requiring it to "clear" its orbit or, in other words, the greatest gravitational force in its world. Orbit, the Daily Mail.

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, the new study reviewed the scientific literature of the last 200 years and found a single publication – from 1802 – that used the requirement of orbiting to classify planets and relied on unfounded reasoning .

"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 Philip Metzger, planet specialist at the University of Florida. Space Institute.

"And that would leave out the second most complex and interesting planet in our solar system."

Metzger 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.

"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 IAU, but they do so because it is useful on the planet. functional plan. "

"It's a neglected definition

"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."

According to Metzger, the literature review showed that the true division between planets and other celestial bodies, such as asteroids, took place in the early 1950s, when Gerard Kuiper published an article making the distinction.

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

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 that the definition of a planet should be based on its intrinsic properties, rather than those that can change, such as the dynamics of the orbit of a planet.

"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," Metzger said.

"This is an important step in the evolution of a planetary body, because apparently, when it occurs, it triggers an active geology in 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."

Last year, astronomers proposed a new way of defining planets based on "the same world physics", citing technical flaws in the definition adopted by the International Astronomical Union in 2006 as the reason for the possible revision.

If accepted, the geophysical definition would essentially classify all "round objects in space that are smaller than stars" as planets, including Pluto, other dwarf planets, and even moons.

Scientists from NASA's New Horizon mission will make their proposal at the lunar and global scientific conference in March.

The team argues that the definition of IAU is imperfect in many ways, especially in that it recognizes only as planets those that revolve around our sun.

This leaves out objects in orbit around other stars or those that gravitate freely around the galaxy.

Along with that, they say that there are parameters that even the planets of our solar system can not satisfy.

According to them, the new definition would meet the needs of scientific classification and "the intuition of peoples".

By the proposed geophysical definition: "A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to take a spheroidal shape properly described by a triaxial ellipsoid regardless of its orbital parameters. "

Or, simply, "round objects in space that are smaller than the stars".

This definition holds the physics of the planet more important than the physics of its interactions with other objects, explain the researchers.

Adopting this definition would see about 110 solar system objects classified as "full-fledged" planets, including dwarf planets and lunar planets such as Ceres, Pluto, Charon and our own moon.

According to the proposal, the new definition would be better for scientists, educators and students because it is more intuitive and emphasizes the intrinsic physical properties of a planetary body.

And this concerns a practice already used.

"In keeping with the intrinsic properties, our geophysical definition is directly based on the physics of the world itself rather than on the physics of its interactions with external objects," explain the authors.

"Our definition captures the current usage already present in the planetary science community.

"In peer-reviewed publications and discussions on planetary sciences, the world" planet "often substitutes for the name of the world, even if the world is a moon or a dwarf planet."