Download THE NINE PLANETS

THE PLANETS
Introduction
In addition to the eight planets, our solar system also consists of the Sun,
numerous other satellites of the planets, and many other comets and asteroids.
The eight planets are:
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Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Classification
Controversy surrounds the classification of these planetary objects.
Typically the solar system is divided into planets (heavenly bodies orbiting the
Sun), their satellites (moons orbiting the planets), asteroids (also orbits the
Sun) and comets (eccentric orbits). According to the Nine Planets web site, the
solar system has been found to be more complicated than the above description
would suggest:
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There are several small moons that are probably captured asteroids.
Comets sometimes fizzle out and become indistinguishable from asteroids.
The Kuiper Belt objects and others like Chiron don't fit this scheme well.
The Earth/Moon and Pluto/Charon systems are sometimes considered
"double planets".
DoeJohnCHSWord
1
3/10/2010
Summary
We have learned much about our solar system, but that knowledge is not
complete. We are still exploring and learning about this vast area called space.
There is still much to learn in the future:
We shall not cease from exploration, and the
end of all our exploring will be to arrive where we
started and know the place for the first time. -- T. S.
Eliot
Controversy surrounds the classification of these planetary objects.
Typically the solar system is divided into planets (heavenly bodies orbiting the
Sun), their satellites (moons orbiting the planets), asteroids (also orbits the
Sun) and comets (eccentric orbits). According to the Nine Planets web site, the
solar system has been found to be more complicated than the above description
would suggest:
Information on the planets can be found at:
http://seds.lpl.arizona.edu
DoeJohnCHSWord
2
3/10/2010