Pluto should become a planet again, scientists say again

It's the cosmic debate that just does not want to die.

Since the International Astronomical Union strengthened its definition of a planet in 2006 and demoted Pluto to dwarf planet status, some astronomers fought.

The latest flush stems from a study conducted by the University of Central Florida's planet scientist, Philip Metzger, who claims that the IAU has been deceived.

Here's how AIU defines a planet: "A celestial body that (a) is in orbit around the Sun, (b) has a mass sufficient for its self-gravity to overcome rigid body forces so that" it adopts a hydrostatic equilibrium (almost round) shape, and (c) cleared the neighborhood around its orbit. "

Pluto ticks the first two boxes, but fails the third because he lives in the Kuiper Belt, a zone of the solar system filled with icy bodies. But Metzger argues that the third requirement is not valid.

According to Metzger, research does not allow us to demand that a planet clear its orbit. He reviewed over 200 years of publications and said that he had found only one, from 1802, that used this requirement to classify a planet and that the only publication was based on reasoning now refuted.

Metzger refers to Pluto as "the second most complex and interesting planet in our solar system" and calls the definition of UAI "neglected". Rather, it suggests that planets are ranked according to their size enough that their gravity allows them to be spherical.

Metzger indicates Pluto's moons and its complex geology and atmosphere, saying "It's more vibrant and alive than Mars".

This is not the first time that scientists are questioning about the definition of IAU of a planet. NASA's New Horizons team, which guided the spacecraft in a close study of Pluto, proposed a radical new definition for planets in 2017. This proposal would reduce Pluto to planet status, but would also qualify some moons and other objects in the solar system of planets.

Lars Lindberg Christensen, IAU press secretary, tells CNET that no resolution has been proposed to review Pluto's classification. "It is nevertheless good and healthy to discuss such topics," he says.

The Metzger study, which focuses on how asteroids were classified differently from planets in the scientific literature, was published online this week in the journal Icarus.

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