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That's the problem with not having a formal and mesurable definition of planet. Although it sounds like things are about more confusing, not less. I heard a piece on the radio this morning that implied that there are 40+ more known things out there that could qualify as a planet under the new definition, including some asteroids made of ice.
the most salient thing about a moon, I would have thought, is that it primarily orbits a planet, and the system formed by planet + moon(s) then orbits the star... thus, an asteroid that doesn't orbit anything else except the star can be a planet if it's big enough, but a moon can't.
sounds like it's all a lot more complicated than I thought.
I saw Mike Brown speak in June. He's funny and quite self-deprecating. He said, "So I guess I'm here today because I've discovered the 10th planet. Or maybe I've eliminated Pluto as a planet. We're, ah, not too sure about that yet." I did not realize he'd called the object Xena!
photo by splunge
photo by TheophileEscargot
photo by Kronos_to_Earth
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