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Name: Megan
Status: other
Grade: other
Location: NV
Country: N/A
Date: N/A


Question:
What does a planet have to have or need to be classified as a planet?


Replies:
In my opinion, a planet needs to be large enough to have condensed as a sphere, and that it cannot be a moon of another planet. If that definition is adopted, it would include Pluto! The IAU definition, which adds that a planet must have cleared out its neighborhood, means the Jupiter and Earth are no longer planets either!

David Levy


Megan,

Astronomers develops the definition of what constitutes a planet. The International Astronomical Union (IAU) meets to determine these definitions as they apply to astronomy. Recently (2006) the body voted to change the definition of a planet based upon information that research in astronomy has provided. Basically, a planet must;

be an object which independently orbits the Sun,

have enough mass so that gravity pulls it into a roughly speroidal shape, and

be much larger than anything else which crosses its orbit.

Science is fluid and can change the definition again if the research warants an addition change. That is how science works.

Steve Sample



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