New study from the University of Central Florida in Orlando indicates that
the rationale for why Pluto lost its planet designation is invalid.
A global organization of astronomers known as the International
Astronomical Union adopted a definition of a planet in 2006 that demanded it
"clear" its orbit, or to put it another way, be the object with the
strongest gravitational pull inside its orbit.
Pluto was no longer considered a planet because of how Neptune's gravity
affects it, as well as the fact that Pluto orbits objects in the Kuiper belt
and frozen gases.However, planetary scientist Philip Metzger from UCF's
Florida Space Institute stated that this threshold for classifying planets
is not supported in the academic literature in a new study that was
published online on Wednesday in the journal Icarus.
Metzger, the study's primary author, searched scientific literature from
the previous 200 years and discovered just one piece—from 1802—that utilized
the clearing-orbit criteria to categorize planets. However, this piece was
founded on logic that has since been disproved.
He said that since Galileo, moons like Jupiter's Europa and Saturn's Titan
have frequently been referred to be planets by planetary scientists.
"The IAU definition would say that the fundamental object of planetary
science, the planet, is supposed to be defined on the basis of a concept
that nobody uses in their research," stated Metzger. The second-most
intricate and fascinating planet in our solar system would also be
excluded."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," the scientist
claimed.The IAU definition, according to Metzger, is "sloppy." "They failed
to clarify what they meant by clearing their orbit. If you take that
literally, there are no planets since none of them are able to complete
their orbits.
According to the planetary scientist, the early 1950s saw the publication
of a study by Gerard Kuiper that established a difference between planets
and other celestial bodies, such as asteroids, depending on how they were
produced.
According to Metzger, even this justification is no longer taken into
consideration when determining whether a celestial body is a planet.
The literature review revealed that clearing orbit is not a standard that
is used to distinguish asteroids from planets, as the IAU claimed when
creating the 2006 definition of planets, according to study co-author Kirby
Runyon of the Johns Hopkins University Applied Physics Laboratory in Laurel,
Maryland. As a result, clearing orbit is not a way to tell apart asteroids
from planets, according to Runyon.
Runyon asserted, "We demonstrated that this is a bogus historical
assertion. Therefore, he concluded, "it is fallacious to apply the same
reasoning to Pluto."According to Metzger, a planet should be defined based
on its inherent characteristics rather than those that are subject to
change, such as the dynamics of an orbit.According to Metzger, dynamics are
not stable; they are always changing. Therefore, they are only the
occupation of a body during the time in question and not the essential
description of a body.
Instead, Metzger suggests categorizing planets according to whether or not
they are massive enough to have a spherical form due to gravity.
And that's not simply a make-believe definition, according to Metzger. It
turns out that this is a significant turning point in the history of a
planetary body since it seems to start active geology when it occurs.
For instance, he pointed out that Pluto possesses a subsurface ocean, a
layered atmosphere, organic molecules, signs of old lakes, and many
moons.
More vibrant and lively than Mars, according to Metzger. The Earth is the
only planet with a more intricate geology.
