This got a lot of attention recently:
LinkQUOTE
Astronomers have found a tenth planet, larger than Pluto and nearly three times farther from the Sun as Pluto is today.
Temporarily designated 2003 UB313, the new planet is the most distant object yet seen in the solar system, 97 times farther from the Sun than the Earth is. It also is the largest body yet found orbiting in the Kuiper belt, the group of icy bodies including Pluto which orbit beyond Neptune.
But is it really a planet? Both Pluto and 2003 UB313 have orbits which are much different from those of "normal" planets.
QUOTE
The discovery is sure to heat up the debate over how to define a planet. Some astronomers claim Pluto is just an overgrown Kuiper-belt object, but Brown thinks it should remain a planet. The International Astronomical Union has avoided a formal definition, but the new object may force the issue. Brown has already proposed a name, but would not disclose it.
To be debated (with, perhaps, less animosity than other debates):
1. Are Pluto and 2003 UB313 really planets?
2. What should 2003 UB313 be named, if we decide it is really a planet?Personally, I tend to think that the Pluto/Charon system and 2003 UB313 are just unusually large Kuiper Belt objects, not significantly different from the many other objects in that distant region of the solar system. Should we say that Ceres, the largest object in the Asteroid Belt, is a planet?
If the size of the object is the big thing, how come nobody says that Quaoar and 2001 KX76 are planets? They are not much smaller than Pluto.
Link to information about QuaoarLink to information about 2001 KX76If we decide that 2003 UB313 deserves a planetary name, we should stick with tradition and use the name of a major deity in the Roman pantheon. For lack of a better idea, I suppose I would suggest Minerva as the name of a new planet. Of the major Roman deities not already honored by a planet or an asteroid, Apollo is too closely associated with the Sun, and Diana is too closely associated with the Moon. Juno would be a possibility, as would Vulcan, but these both seem somehow not quite appropriate.