According to the 5A resolution, a Planet is a Celestial Body that,
- is in an orbit around sun.
- has enough mass and gravity to overcome rigid forces.
- has not cleared the neighborhood.
- and is not a satellite.
- Pluto is smaller than any planet in solar system, even it is smaller than Earth's Moon.
- Pluto is dense and rocky, but different from its neighborhood planets (Jupiter, Saturn, Uranus, Neptune) which are gaseous. (so many scientist believe that it may be formed somewhere else and attracted due to Sun's gravity. /li>
- one of it's moon, Charon is almost half of its size. and this kind of systems may be considered as binary systems.
- Pluto's orbit is completely different than other planets as seen below:
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