The International Astronomical Union (IAU) meeting in Prague this week has defined “planet” as nine through eight, ending Pluto’s membership. Nearly 2,500 scientists who participated in the meeting have come to this conclusion.
The size of Pluto, discovered in 1976 and shrunk ever since, has generated controversy for decades. It is now 2,300 kilometers wide. The discoverer, Clyde Tombaugh (1906-1997), who first discovered it 76 years ago, is still considered the father of the planet.
While the Earth has a circumference of 12,750 kilometers and a volume of 3,480 kilometers, and 2003-UB313 (about 3,000 kilometers) is much farther from Earth, Pluto is only about 12,750 kilometers high and a volume of only 3,480 kilometers.
“A celestial body in orbit around the Sun is said to have sufficient mass to have self-gravity to overcome the rigid forces of a body so that it assumes a balanced hydrostatic shape, that is, round, and has been cleared of its immediate shape. “. neighborhood of its orbit.
“A dwarf planet is a celestial body in orbit around the Sun that has sufficient mass to have self-gravity to overcome rigid-body forces so that it can assume a balanced hydrostatic shape; it has not cleared the neighborhood of its orbit and is not al satelite.
“All other objects orbiting the Sun are collectively considered ‘small Solar System bodies’.”
It is incorrect to say that Pluto’s orbit is unusual in that it is not parallel to that of Earth and the seven other planets in the Solar System.
A planet is a celestial body that is larger than a solar system body but not as large as an exoplanet.
Now, according to this definition, the planets of the Solar System are now eight, instead of nine: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune (ordered by their proximity to the Sun, from smallest to largest). .
In 1930, Pluto was discovered to be a planet and thus loses its planet status and continues to be part of the Solar System as a “dwarf planet”.
There are two options.
When nine experts adopted a common position in 2001, the alternative was to downgrade Pluto to a “dwarf planet” or expand the number to twelve by adding Ceres, Charon and 2003-UBS313 to the list.
As the sessions progressed, the experts who chose to remove Pluto’s ‘status’ from Mars became increasingly influential.
It is also likely that the 2003-UB313 election will be postponed until the XXVII IAU General Assembly, to be held in Rio de Janeiro in 2009.