Time for a new mnemonic device, J
The prestigious international group in the Czech Republic today spelled out the basic tests a celestial body needs to pass before it can be deemed a planet: "A celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a . . . nearly round shape, and has cleared the neighborhood around its orbit."So rather than promoting three new planets, Pluto gets the boot after 76 years (astronomy geeks will recognize that amount of time as the the interval between visits of Halley's Comet). A quibble, though. If it's the third criteria that got Pluto ejected from its prime celestial classification, wouldn't it be just as easy to say that Neptune isn't a planet because it failed to remove Pluto from it's orbital path? Wasn't it an arbitrary decision to pull Pluto's status, leaving Neptune's reputation intact despite that planet also failing to meet the third criteria?
It's the last part of the definition that doomed Pluto. Its oblong orbit overlaps with Neptune's.
Pluto will now be reclassified in a new category of "dwarf planets," similar to what astronomers have long called "minor planets."
I'm calling out the International Astronomy Union on their bunk and arbitrary anti-Pluto zealotry!