Pluto No Longer a Planet
Why is Pluto no longer a planet?
Yes, Haylee, there is a planet named Pluto. However, a group of
people at the "International Astronomical Union" voted to define
the solar system differently from what it was. Now there are 8
regular planets-- Mercury, Venus, Earth, Mars, Jupiter, Saturn,
Uranus, and Neptune. There is now a new class of worlds called
"dwarf planets". That includes our friend Pluto, and -- here is
the good news-- it also includes the asteroid Ceres, the biggest asteroid.
planet?" Lots of them say no, but I disagree. Did you know that
our Sun is a dwarf star? And it is of course a star. So I am
going to keep on calling Pluto a dwarf planet, until someone tells
me I cannot.
Haylee, with me, your question is very personal. I knew Clyde
Tombaugh, the man who found Pluto, very well. In fact I wrote his
biography Clyde Tombaugh: Discoverer of Planet Pluto. He is no
longer living but his wife and family is. So I thank you for
asking your question.
David H. Levy
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Update: June 2012