Pluto was erstwhile classified as a planet, and the smallest planet in our solar system, until it was demoted from the classification of planets and reduced to a “dwarf planet” through a 9-8 vote in 2006 by the International Astronomical Union (IAU). Pluto was before this time taught in schools as the 9th planet in our solar system, but since the demotion to the status of a dwarf planet by the IAU, its classification and status has continued to generate international debates.
The Harvard-Smithsonian Center for Astrophysics met recently for a debate and revisited the status of Pluto, arguing whether it should be reinstated as the 9th planet in our solar system or remain at its demoted status as a dwarf planet. High-powered space authorities were present at the meeting, including Dr. Owen Gingerich, the former chairman of the IAU’s planet definition committee who was himself a part of the team that demoted the status of Pluto from a planet in 2006.
Ultimately, the IAU has been able to define a planet as a celestial body that meets three criteria: it orbits the sun; has a rounded shape with sufficient mass to sustain hydrostatic equilibrium; and has cleared the neighborhood of its orbit. Any non-satellite body that does not meet these three conditions cannot be classified as a dwarf planet.
Although the decision reached at the Harvard-Smithsonian debate is not authoritatively official and final, it could influence further debate about whether the IAU should revisit the issue and reinstate Pluto as the 9th planet in our solar system instead of just being a mere dwarf planet that is related to some asteroids. According to the argument at the debate, “even though a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster.”