The point of my definition, though, is to make determining whether an object is a planet actually useful for our understanding of the formation of the solar system, rather than merely a stamp-collecting exercise.
As to your example, if I found a rocky, Mercury-sized object in the Oort cloud (which I think is what you meant, as Kuiper belt objects are thought to have formed in the proplyd), I'd have to conclude that it wasn't a comet, just the same as if I found a brown dwarf in the Oort cloud I'd have to conclude that it wasn't a comet.
I don't mean to claim that mine is the only such definition. Maybe a definition like "any astronomical object with a metallic core surrounded by other material" would better match our current expectations.
to make determining whether an object is a planet actually useful for our understanding of the formation of the solar system My father (http://www.ociw.edu/research/sshectman/) pointed out to me that this definition will have zero effect on what science professional astronomers do. The only actual scientific effect it might have is on how much PR, and thus funding, they get, and so the best definition is the one that will get the most headlines going forward. Be too permissive and planet discoveries aren't news. Too strict and they don't happen often enough. The rounded bodies definition is probably about the right balance.
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momijizukamori
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Date: 2006-08-18 02:12 pm (UTC)As to your example, if I found a rocky, Mercury-sized object in the Oort cloud (which I think is what you meant, as Kuiper belt objects are thought to have formed in the proplyd), I'd have to conclude that it wasn't a comet, just the same as if I found a brown dwarf in the Oort cloud I'd have to conclude that it wasn't a comet.
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Date: 2006-08-18 03:09 pm (UTC)I don't mean to claim that mine is the only such definition. Maybe a definition like "any astronomical object with a metallic core surrounded by other material" would better match our current expectations.
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Date: 2006-08-22 05:30 am (UTC)My father (http://www.ociw.edu/research/sshectman/) pointed out to me that this definition will have zero effect on what science professional astronomers do. The only actual scientific effect it might have is on how much PR, and thus funding, they get, and so the best definition is the one that will get the most headlines going forward. Be too permissive and planet discoveries aren't news. Too strict and they don't happen often enough. The rounded bodies definition is probably about the right balance.