I don't doubt the scientific definition of a planet would exclude Pluto. HOWEVER, the long history
of calling it a planet is an excellent and nostalgic reason to keep doing it. Plus there is really
no harm to calling it that. The scientists already know what it is and isn't regardless of the
common term planet so it harms nothing to keep calling it that. It can even continue to be an
excellent teaching example in kid's textbooks as they review the for and against for calling it a
planet and debate it in class. Absolutely no harm at all in continuing to call it a planet. It's
not like NASA is going to make a crucial miscalculation because some new guy gets confused about
what Pluto is.
It's actually likely that Pluto will become a planet again in the near future, along with several
other large objects in the Kuiper Belt. We're probably going to go from 9 planets to 8 planets to,
at least last I heard, 11 planets, in the next several years.
Like the fact that Pluto is just another object in the Kuiper Belt, and that there are other objects that are the same size as or bigger than Pluto? If you want to count Pluto as a planet, we're going to have a lot more. Eris is in the Kuiper Belt also, and larger than Pluto. 2005 FY9 is only slightly smaller. That's 11 planets so far. There are many more than that.
Pluto is still a planet; it's just been down graded to a dwarf planet. It's the second-largest known
dwarf planet in the Solar System. Pluto is even smaller than out moon.
Regardless of who's talking, whether it be the International Astronomical Union, astronomers in
general or laymen, Pluto fails to meet at least one criterion for a planet in every definition.
Only the loosest definitions include Pluto and would thus include Ceres, the biggest asteroid in the
belt, among many other objects.
There is no agreed definition of a planet. The most common criteria in all definitions are:
- solid
- spherical
- has enough mass to form its own gravity
- does not produce nuclear reactions
- has a regular orbit around a star
With those as criteria, Pluto is not a planet because it doesn't have the last one. If you insist
the last is true, then many comets become planets.
Without a definitive list agreed to by all, this is a Sisyphean debate.
What's all this bull about people caring whether or not Pluto is a planet? Trust me, Pluto's
feelings weren't hurt.
According to the definition of planets, Pluto isn't one of them. What's so bad about that?
Do you think the scientists had an agenda? They wanted to revoke Pluto's planethood to hurt it's
reputation? They're scientists. It's their job. And usually, they do it very well. In this case,
they did.
28 Jul 2008 16:38
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