Sayonara Pluto, Happy To See You Go

I am happy to see Pluto demoted from planet status. Pluto is not only smaller and much less massive than any other planet but it is even less than 0.2 lunar mass. It is also smaller and less massive than seven moons: Ganymede, Titan, Callisto, Io, Earth’s Moon, Europa and Triton.

If Pluto could be a planet why not our moon? At last justice has been done at a planetary scale and Pluto downgraded to its proper position, muhuhahaha.


Frankly, I couldn’t care less. I fail to see what this brouhaha is about. If it was upto me Pluto & Ceres would simply be classified as yet another celestial body like asteroids in Kuiper belt. Mass should definitely be a critera to determine planetiness (my word) of any celestial body (size does matter here). Otherwise you could throw some junk (truckloads of peticide coke perhaps?) into a planetary orbit around the sun and ask for planet status, no?

The current definition of planet is less ambiguous. The International Astronomical Union has defined planet as a celestial body that:

1. is in orbit around a star or stellar remnants;
2. has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape;
3. is not massive enough to initiate thermonuclear fusion of deuterium in its core; and,
4. has cleared the neighbourhood around its orbit.

The nomenclature of “Dwarf planet” is compromise to satisfy scientists whose ego has been seriously ruffled by this demotion. It doesn’t make much sense. On the other hand “has cleared the neighbourhood around its orbit” clause doesn’t make much sense either. In conclusion I think IAU has taken a step in the right direction.
Disclaimer: IANAA