[Telepathic Intruder]

In the end it's just a word, and word definitions change according to people's outlooks. Originally it meant something very specific: a star that wanders, not fixed in place like the rest. There were only 5 of them among the countless other stars, and the Earth wasn't even one of them. Then, starting with the telescope, our understanding of the universe grew. Planets were actually large bodies orbiting the sun, as was the Earth, having lost its imaginary place at the center of the universe.

As we found more and more objects in the solar system, the word 'planet' became more difficult to define. But there is a more esoteric meaning that has to do with Nebular theory of planet formation. Planets coalesce from a huge number of smaller planetesimals, each scooping out their own orbits from the random flying debris as they grow. At the end of the process you have large planets with their own individual orbits and no other objects threatening to replace them. This is how nature defines a planet. Objects such as asteroids and KBO's are formed in a different way.

So the question is, do we let the astrophysicists who understand the process define the terms, or the average person who just thinks it would be cool if Pluto is called a planet again? Or does it even matter at all?

[DoodleBob]

I’m just a dopey guy in FR. This issue is up to the experts, is DOES matter, and that was Stern’s point. He argues that the definition of a planet was altered to cap the number at 8. Stern argues that the definition should be true and if the number of planets grows to 27, then so be it. His analogy, about the Periodic Table, is compelling.