Pluto is not suitable

Poor Pluto. His days as one of the nine planets of our solar system may be numbered. Two groups of researchers at the International Astronomical Union are considering redefining the minor planet

June 2008 – The past Neptunian dwarf planets will be Plutoids

Poor Pluto. His days as one of the nine planets of our solar system may be numbered. Two groups of researchers at the International Astronomical Union are considering redefining the minor planet.

"It's been clear for 20 years that Pluto is not suitable," says astronomer Mike Ahern of the University of Maryland, head of a department in the Astronomical Union. The diameter of Pluto, the farthest planet from the Sun, is only 2,304 km. Even smaller than the moon. What's more: while the orbits of the other planets are circular, Pluto's orbit is elliptical and at times it comes even closer to the Sun than Neptune, the eighth planet from the Sun. Aharon seeks to create a new classification of celestial bodies that move beyond Neptune: trans-Neptunes. Pluto will be trans-Neptune number 1. On the other hand, Brian Marsden from the Union's Asteroid Center, prefers to classify Pluto as an asteroid, which will probably receive the coveted serial number 10,000. "This is not a demotion", says Marsden, "It is an honor".
Astronomer Alan Hale, one of the discoverers of Comet Hale-Bopp, claims that the argument is rather silly. There is no clear definition of a planet, he says. "A hypothetical inhabitant of Jupiter would laugh at the fact that we call Earth a 'planet'."