Pluto was once known as the ninth planet in the Solar System until the International Astronomical Union (IAU) demoted it to a dwarf planet in 2006 despite many scientists not agreeing to the decision. IAU said that Pluto only met the two criteria of a planet, hence the demotion.
In a renewed protest, a group of scientists wants IAU to reclassify Pluto as a planet along with the moons in the Solar System and any other cosmic bodies that meet the definition of a planet used in the 16th century.
Pluto is A Planet: Scientists Ignore IAU Guidelines and Classify Moons in the Solar System as Planets
What is the 16th Century Definition of a Planet?
After demoting Pluto, the IAU has listed only eight planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. But a previous report of Science Times cited a recent study published in the journal Icarus claims that the IAU definition of a planet is based on folklore and not science, harming scientific research and understanding of the Solar System.
Yahoo! News reported that the researchers of the new study said that Pluto should be known as a planet under a 16th-century definition of planets, which scientists have used for many scientists. It defines planets as any cosmic bodies that are geologically active.
Researchers argue that using this definition, Pluto and other objects in space such as asteroid Ceres, moons Europa, Enceladus, and Titan are considered as planets. Study lead author Philip Metzger, a planetary physicist at the University of Central Florida, claims that there are probably 150 planets in the Solar System using the 16th-century definition.
The study came after data from the 2015 Pluto flyby of NASA's New Horizons probe showed new insights on Pluto's status in the Solar System.
Planetary Scientists Say Pluto is A Planet
Since many scientists do not accept the definition set by the IAU, they claim that they are still calling Pluto a planet in their papers and considered Titan and Triton and other moons planets, too. As better techniques and telescopes, with the James Webb Space Telescope recently launched, the definition for a planet gains more importance now.
Even former NASA Administrator Jim Bridenstine said he still believes Pluto is a planet, FOX News reported. During his talk at the University of Colorado in 2019, he expressed his views on Pluto's status and said he sticks by his belief that Pluto is a planet.
Meanwhile, IAU told FOX Television Stations in a statement that they respect all scientific opinions and welcome a debate regarding the matter. They noted that proposed resolutions should be submitted to the Resolutions Committee during the General Assembly, which happens every three years. More so, they are open to receiving unsolicited submissions from members of the community.
On the other hand, scientists said that the definition of planets in the Solar System might not be applied to other star systems because few very large planets orbited by large moons circle around their star instead of a handful of planets that orbit at large distances.
"Because of the diversity of planetary architectures that we're discovering, we think it's important to get it right at this time," Yahoo! News quoted Metzger.
RELATED ARTICLE: Pluto Demotion to Dwarf Planet Rooted in Folklore? Scientists Want to Reinstate It, Make Moons As New Planet
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