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To: pjd

What does that mean, hasn’t cleared it’s orbit?


14 posted on 02/03/2017 5:16:00 PM PST by Mean Daddy (Every time Hillary lies, a demon gets its wings. - Windflier)
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To: Mean Daddy

https://en.wikipedia.org/wiki/IAU_definition_of_planet#Substance

The wording of the final draft of the definition has continued to be criticized, primarily in the United States. Notably, Alan Stern, the lead scientist on NASA’s robotic mission to Pluto, has contended that Earth, Mars, Jupiter, and Neptune have not fully cleared their orbital zones, just like Pluto. Earth orbits with 10,000 near-Earth asteroids. Jupiter, meanwhile, is accompanied by 100,000 Trojan asteroids on its orbital path. Stern has asserted: “If Neptune had cleared its zone, Pluto wouldn’t be there.”[43]

Some astronomers counter this opinion by saying that, far from not having cleared their orbits, the major planets completely control the orbits of the other bodies within their orbital zone. Although Jupiter does coexist with a large number of small bodies in its orbit (the Trojan asteroids), these bodies only exist in Jupiter’s orbit because they are in the sway of the planet’s huge gravity. Earth accretes or ejects near-Earth asteroids on million-year time scales, thereby clearing its orbit. Similarly, Pluto may cross the orbit of Neptune, but Neptune long ago locked Pluto and its attendant Kuiper belt objects, called plutinos, into a 3:2 resonance (i.e., they orbit the Sun twice for every three Neptune orbits). Since the orbits of these objects are entirely dictated by Neptune’s gravity, Neptune is therefore gravitationally dominant.[44]


18 posted on 02/03/2017 5:44:45 PM PST by Lonesome in Massachussets (Psephomancers for Hillary!)
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