August 30, 2006

From T.R. Stone:

Re: Pluto no longer a planet (Aug. 24): I’m in complete agreement with Hal Weaver of Johns Hopkins University on this issue: the caveat about “clearing the neigh­bour­hood around its or­bit” is pointless and arbitrary. First of all, that should technically mean that a “planet” can’t have a moon. Secondly, one could ask: “clearing the neigh­bour­hood” to what degree? Will the concentration of smaller objects in the space which makes up the planet’s so-called “neighborhood” have to have a predefined maximum value of so many bodies per unit volume to qualify? This whole “definition” flap is a prime example of how foolish even people with PhDs can be.

Just go with something simple, eggheads: “A planet shall be considered to be any non-self-luminous/non-incandescent body in orbit around a star, said body having sufficient size to gravitationally assume a spherical shape, said shape being considered spherical if it presents an ellipsoid having an eccentricity not exceeding (such-and-so a value).”

Fix the eccentricity limits right, and you cover bodies that go from perfectly spherical (eccentricity = 0) to noticably ellipsoidal (like Saturn), while excluding the obvious potato-shaped monstrosities like alot of the asteroids. And there you have it; a definition which doesn’t entail nebulous concepts like “clearing the neigh­bour­hood around its or­bit of smaller objects”.

Now, how hard was that? ;-)

T.R. Stone
Omaha, NE


Post a Comment

<< Home