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Unformatted text preview: e compared to Pluto Large Use orbit to measure masses Use
Earth Masses 0.000210 0.000025 Moon Moon Masses Masses 0.175 0.021 HST Image 1978 Discovery Image Pluto Charon Pluto, Neptune, Triton connection? connection?
Pluto crosses Neptune’s orbit Pluto orbit Both Pluto and Neptune’s moon Triton Both moon are effectively Kuiper Belt objects Kuiper People have tried and failed to link the three together via some 3-way three way gravitational encounter gravitational Plutoids: Dwarf Planets Plutoids Dwarf wikipedia wikipedia What is a Planet? IAU 2006 What
1. Large enough to be spherical due to its own gravity - Larger than about 500 km diameter pro: depends only on properties of body (planetary scientists like it) con: dozens of moons meet this criteria including 5 larger con: than Pluto and 2 larger than Mercury (4900 km) 2. In orbit around the Sun 2. 3. Has cleared its orbit of debris Dynamical Criteria Excludes: Pluto, Ceres (largest asteroid), Moons and Kuiper Excludes: Kuiper Belt Objects (e.g. Eris/Xena) Pluto and Ceres are dwarf planets because they fail 3. Pluto because...
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