<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by thebobgy</i>
<br />do you have a better definition of what constitutes a planet?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The distinction between planets and asteroids is entirely man-made because nature hasn't yet given us one. As a first cut, I might use "hydrostatic equilibrium" (spherical shape) as a sufficient condition to be a planet. Yet, according to fission theory, bodies big and small start out as hot balls of gas that necessarily become quite round before they cool and solidify. And that would happen for bodies of any size. So the present definition depends on the composition of the planet and the strength of those materials in ways we do not yet fully understand.
Then there's the problem that, according to Meta Science, Mercury, Mars, and Pluto are former moons that fissioned from planets, not planets that fissioned from the Sun. Yet I think the public isn't ready to start decommissioning traditional planets just to satisfy some theoretical constraints.
So ultimately, I liked the compromise proposal that the IAU's committee recommended: The traditional nine planets plus Ceres, Charon, and Eris (formerly Xena), plus anything else bigger than Pluto. That keeps the number of planets small enough for school children to learn, and keeps hope alive for future would-be planet discoverers. I'd argue we can't do better until we're a lot smarter about the origins and evolutions of all kinds of solar system bodies.
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">given you are good with facts, can you invoke emotion or sentiment?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I've gone to great lengths to suppress any emotional investment in my ideas or anyone else's. Biases interfere with progress. So I'm not a good candidate for leading a charge that requires evoking emotion or sentiment.
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">if not, do you have or know a good PR person?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Yes, but not one without baggage. But maybe, for a purely public appeal, baggage is not so important.
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The sentiment in question is not about Pluto but Earth; if Earth is not a planet by definition then what are we “space debris”?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The IAU says that everything below planet level is a "small solar system body". Carl Sagan once said that our solar system consisted of one star, four planets, and a lot of debris. In that view, we live on a piece of debris.
But that's what this issue is about -- where to draw the line. -|Tom|-
