What is a Plutoid?
Last month, the IAU also reclassified Pluto, and any other dwarf planet or round object beyond Neptune, as a so-called plutoid. Like dwarf planets, plutoids must orbit the sun and be massive enough to maintain a nearly round shape. But they also must be located beyond the orbit of Neptune, which circles the sun every 165 years from a distance of about 30 astronomical units (AU). One AU is the distance from the Earth to the sun, or about 93 million miles (150 million km). It should be noted that according to the IAU, the small moons of dwarf planets or plutoids cannot themselves be considered as dwarf planets or plutoids. What’s in a name? The three designations have taken center stage in recent years as astronomers spot new objects and refine the orbits and attributes of other known, but distant, solar system bodies. There are other, even odder designations – things like plutons, plutinos, centaurs and EKOs – but when it comes to actually naming something, the IAU wins out. Take Makema
” a. Something the doctor has to surgically remove. b. A new Transformers action figure. c. A throat lozenge. d. The name for the most abundant type of planet in the solar system. If you guessed “d” you’re right. Pluto, the Rodney Dangerfield of the solar system, is now officially a “plutoid’ according to a June 11 announcement by the International Astronomical Union (IAU) Committee on Small Body Nomenclature. You’ll remember that underdog Pluto was unceremoniously demoted to a “dwarf planet” in a raucous IAU General Assembly meeting in 2006 that shrunk the solar system to eight normal planets. This triggered a public backlash with protest slogans like: “size doesn’t matter!” The General Assembly debated whether Pluto fulfilled all the definitions of a planet. It almost did, except for one sticking point. Pluto doesn’t sweep out a clean orbital path but instead lives in a cluttered neighborhood. Pluto is one of the largest know members of the Kuiper belt, an outer debris field of perha
Last month, the IAU also reclassified Pluto, and any other dwarf planet or round object beyond Neptune, as a so-called plutoid. Like dwarf planets, plutoids must orbit the sun and be massive enough to maintain a nearly round shape. But they also must be located beyond the orbit of Neptune, which circles the sun every 165 years from a distance of about 30 astronomical units (AU). One AU is the distance from the Earth to the sun, or about 93 million miles (150 million km). It should be noted that according to the IAU, the small moons of dwarf planets or plutoids cannot themselves be considered as dwarf planets or plutoids. What’s in a name? The three designations have taken center stage in recent years as astronomers spot new objects and refine the orbits and attributes of other known, but distant, solar system bodies. There are other, even odder designations – things like plutons, plutinos, centaurs and EKOs – but when it comes to actually naming something, the IAU wins out. Take Makema
A plutoid is a celestial body similar to Pluto in configuration. The term “plutoid” was chosen as a consolation nod to Pluto’s former glory as the ninth planet, although it did not resolve the controversy over the precise definition of a planet, let alone whether or not Pluto should be considered a planet. Along with Pluto’s official redefinition as a plutoid came the discovery that as many as 70 celestial bodies may qualify as plutoids, which means that Pluto is far from being alone. Several characteristics define a plutoid. Plutoids are dwarf planets, which means that while they enough mass to have become rounded and achieved a specific orbit around the Sun, they have not managed to “clear the neighborhood,” as astronomers say. In this case, clearing the neighborhood refers to a celestial body which has become gravitationally dominant, removing objects of a similar size from its orbit, or pulling large objects into orbit around it, like the Earth has done with the Moon. In other word
A plutoid is an astronomical body that is, um, like Pluto. So, Pluto is now redefined as a thing that is like Pluto. Isn’t that a bit circular, and unimaginative? The astronomers had this chance to set things right after throwing a big hissy about Pluto not, not, not being a planet. They could have done Pluto the honor of having, after its rejection from the pantheon of the Solar System, having a nice new definition to reside in. But oh, no. The astronomers decided that they would define Pluto as a plutoid, which is a thing that is like Pluto. If the astronomers were going to just make up a new name for the category of rejected planets, they could have at least been more imaginative and dramatic. They could have come up with a new name to make people stand up and take notice. They could have declared that Pluto is a zipthwat. I hereby nominate zipthwat. At least the name zipthwat is not circular. You could say, “Hey, they discovered a new zipthwat today!” Your friend would respond, “Wh
