Pansson P.

asked • 07/07/15

How many planets in our solar system

In what order are the planets from the sun

3 Answers By Expert Tutors

By:

Alan B.

There were three basic reasons Pluto was downgraded to a dwarf planet:
1)  it has very little mass and is small in size
2)  its orbit crosses that of Neptune's, as it acts almost as a satellite of Neptune
3)  Hundreds of other "planets" the same size as Pluto have been found
 
Percival Lowell first proposed that Pluto existed based on observing perturbations (wobbles) in Neptune's orbit as Pluto passed nearby.  Lowell died before finding Pluto.  His assistant, Clyde Tombaugh, eventually found Pluto, so the planet has a Greek name from the god of the underworld (as it is cold and dark so far from the sun), and honors Percival Lowell (PL) and (logic symbol U for union) and Clyde TOmbaugh (part of whose ashes were on the recent flyby spacecraft - July 2015).
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07/31/15

Michael W. answered • 07/07/15

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5.0 (345)

Experienced Biology teacher/tutor/nestor

Philip P.

tutor
Sorry about the over-post. Michael (both W. and J.).  For whatever reason, your answer and Michael J.'s did not show up this morning and the student's question was showing as unanswered.  Normally, I won't post an answer if a tutor has already posted a correct answer.
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07/08/15

Michael J. answered • 07/07/15

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Effective High School STEM Tutor & CUNY Math Peer Leader

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