Monday, 20 February 2023 | 17:51
Aulia Hafisa
Illustration of Pluto (Shutterstock)

TheIndonesia.id - The International Astronomical Union (IAU) demoted Pluto from its position as the ninth planet from the Sun in 2006. Why Is Pluto no longer a planet?

The 2006 event of the General Assembly of the IAU came to demote Pluto after a fierce debate on the definition of the term planet. It was once a loose word used to describe a large object within the solar system. Then, the term "planet" is specified to be celestial objects large enough to be made rounded by their gravitational orbit around the sun and to have shooed away neighboring planetary objects and debris. 

What Is Pluto now?

Now, Pluto is classified as a dwarf planet because while it is large enough to have become spherical, it is not big enough to exert its orbital dominance and clear the neighborhood surrounding its orbit. 

Facts about Pluto

Solar system illustration (Shutterstock)

Strange Ways of Orbiting

Pluto has a highly elliptical orbit that is not on the same track as the other eight planets. Pluto orbits the sun at a distance of 3.65 billion miles (5.87 billion km) and takes 248 years to go around the sun. The odd orbit means that for several years at a time, Pluto's orbit overlaps that of Neptune's. This brings Pluto closer to Earth than Neptune, the eighth planet from the sun. 

Very cold planet

Pluto is claimed to be one of the coldest planets among plants in the Solar System. Researchers call the hydrocarbon particles in Pluto's atmosphere responsible for the dwarf planet's extremely low temperatures. Quoting Space, Pluto is the only planet known to have a temperature that is driven more by haze particles than by gas molecules.

The researchers wrote about this in the online journal, Nature. Modeling work based on the composition of Pluto's atmosphere has predicted that temperatures there will hover around minus 280 degrees Fahrenheit or minus 173 degrees Celsius. But when NASA's New Horizons Pluto probe approached the planet in July 2015, temperatures there were recorded about 53 degrees Fahrenheit (30 degrees Celsius) lower than expected.

The Name "Pluto" Was Proposed by an 11 Year Old Girl

The little girl's name is Venetia Burney, a student from Oxford, England. When the discovery of this ninth planet was announced on March 13, 1930, the planet had not yet been named. Venetia, who knew that the previous Planet's name was taken from the name of a Greek God, suggested the name 'Pluto' which was the name of the Greek God of the Underworld. 

Due to the efforts of his grandfather, Falconer Madan, head librarian at the Bodleian Library at the University of Oxford in England, the name 'Pluto' which was coined by Venetia was finally chosen and is used today. 

Pluto Was a Giant

There is a theory that Pluto was once a giant. The planet Pluto was first discovered on February 18, 1930, at the Lowell Observatory in Flagstaff, Arizona, by astronomer Clyde W. Tombaugh with contributions from William H. Pickering.