Fight for Pluto !, A Campaign to Reverse the Unjust Demotion Options

[mars loon]

Dear Friends,

Today I am extremely dissapointed that the Pluto Demoters have triumphed.

I respect their opinion, but disagree with it.

I strongly agree with Alan Stern's statement calling it "absurd" that only 424 astronomers were allowed to vote, out of some 10,000 professional astronomers around the globe.

This tiny group is clearly not at all representative by mathematics alone.

I believe we should formulate a plan to overturn this unjust decision and return Pluto to full planetary status, and as the first member of a third catagory of planets, Xena being number two. Thus a total of 10 Planets in our Solar System

Please respond if you agree that Pluto should be restored as a planet.

ken

Ken Kremer
Amateur Astronomers Association of Princeton
Program Chairman

[Greg Hullender]

What is the boundary on the ability of a planet to hold a hydrogen atmosphere? If I remember right, there's an exponential function of time in the equation, so the boundary should be fairly sharp. That seems like the most logical boundary between Terrestrial planets and Giant planets. Or is that already 10 MEarth?

As for "planetoid" meaning small, I know that was the historical meaning, but I think most people know that in general -oid just means "similar to." Lay people don't think "humanoids" are little humans, and I'm pretty sure scientists don't think spheroids are little spheres. :-) I think "planetoid" could work -- meaning that everything from Ceres to Jupiter would be a planetoid -- if the right people got behind it. That might just be you and Mike. :-)

[JRehling]

What is the boundary on the ability of a planet to hold a hydrogen atmosphere? If I remember right, there's an exponential function of time in the equation, so the boundary should be fairly sharp. That seems like the most logical boundary between Terrestrial planets and Giant planets. Or is that already 10 MEarth?

It depends upon temperature. Go out to where it's 2K, and a pebble of solid hydrogen would hold itself. Orbit just above the corona and Neptune couldn't hold it together. The latter type of world has been named "chthonian", in case we find any.

I raise an eyebrow at the idea that temperature would become such an important determining characteristic of "planet". But then I raise an eyebrow at any characteristic that is ex post facto to usage and tries to "reverse engineer" what people mean. When you find yourself needing such factors, it's time to concede that there isn't a natural category that deserves a precise definition. I don't know why people have such a hard time even addressing that point. I've heard people refer to "Nobel Prize fever" before. I think the main phenomenon we have here is "definition fever". Something big is (possibly) going to be decided and people would rather be a part of defining something than deciding not to define something. So the awkward definitions come rapid fire.