Plutoids: a new class of objects beyond Neptune, Astronomy, politics or damage control |
Plutoids: a new class of objects beyond Neptune, Astronomy, politics or damage control |
Jun 12 2008, 09:44 AM
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Member Group: Members Posts: 340 Joined: 11-April 08 From: Sydney, Australia Member No.: 4093 |
Article on the BBC website: 'Non-planet' Pluto gets new class
http://news.bbc.co.uk/2/hi/science/nature/7449735.stm QUOTE Now an IAU committee, meeting in Oslo, has suggested that small, nearly spherical objects orbiting beyond Neptune should carry the "plutoid" tag. It also goes on to say that not everybody is too excited about it: QUOTE "It's just some people in a smoke-filled room who dreamed it up," he told the Associated Press. "Plutoids or haemorrhoids, whatever they call it. This is irrelevant." -------------------- |
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Jun 15 2008, 02:02 PM
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Nearly all English words are a bit fuzzy -- even scientific ones. Take "star" for example. Is a brown dwarf a star? If we agree stars have to fuse, then is a white dwarf no longer a star? How about a quasar -- is that a star? And is there a star so small that if we removed a few kilograms it would cease to be a star? Also, important distinctions like type G vs. type K are almost completely arbitrary.
Note that even the definition that says a planet is any non-fusing body that's large enough to be in hydrostatic equilibrium does have this fuzzy edge problem -- on the high and low ends both. The fact that words have fuzzy meanings doesn't mean they're useless, but it does mean you need to think carefully about what you want to get out of a definition. Also, and most germane to the "what's a planet" questions, do you have enough examples to make a useful definition? If we cast the problem as "how should we classify subtypes of non-fusing bodies in hydrostatic equilibrium," then I'd claim that since we only know of a couple dozen such bodies, it's not at all clear that we have enough data to make a proper definition. When we know of hundreds such bodies, we'll have a much better chance at knowing what's important and what's not. Until then, we're just guessing, and debate without data is almost always sterile. --Greg |
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