Our Solar System consists of the Sun, the nine planets, and
various moons, asteroids and comets. The Sun is a giant sphere,
composed mostly
of hydrogen gas that is held together by its own gravity. It weighs
about 2x1030 kilograms, and is about
1.4x109 meters
in diameter. Many of the nine planets that orbit the Sun have
moons orbiting them; with almost 40, Jupiter has the largest number of
moons in the Solar System. Asteroids are
similar to planets, but smaller in size and with different
chemical compositions. Comets are made up of dust and ice (frozen water
and gas) that orbit the Sun in highly eccentric orbits. When they
approach the Sun, their long dusty tails become visible, which can be
almost 10 million kilometers long. Beyond the orbit of Pluto is
a population of many icy planetesimals. Some of these objects may, from
time to time, become dislodged, traveling to the inner Solar System to
become comets.
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that image. Visit
non-NRAO website for more information on the Solar System.
