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Saturn, the sixth planet from the sun, is
the second-largest planet in the solar system,
smaller only than Jupiter. Saturn is easy
to identify because of the large, beautiful
system of rings surrounding it. Like Jupiter,
Uranus, and Neptune, Saturn is a gas giant.
It is made mostly of hydrogen and helium,
with crystals of ammonia in the upper layers
of its atmosphere, which is what gives it
its pale yellow color.
Although the outermost layers of Saturn are
made of gasses, scientists believe that if
you traveled down through the atmosphere,
you would eventually find that the hydrogen
and helium became liquid, and even farther
down, metallic, and in the center of the planet,
they believe there is a hard rocky core.
Saturn is the least dense planet in the solar
system. Although it is much larger than the
Earth - about nine times wider and 95 time
more massive - it is only about 12% as dense
as the Earth is. That means that if you were
able to find a bathtub large enough, Saturn
would float in the water!
Like Jupiter, Saturn has storms and stripes
of clouds, they are just harder to see because
of their pale color. However, winds on Saturn
are much faster than Jupiter's winds. Saturn
has the second-fastest winds in the solar
system, reaching speeds of 1800 km/h. The
only planet with winds faster than Saturn
is Neptune.
Saturn is far from the sun - about 890 million
miles or 1.4 billion kilometers away. As a
result, it takes a very, very long time to
travel around the sun - about 29 years. However,
it spins - or rotates - much more quickly
than the Earth does. Instead of rotating once
every 24 hours, Saturn's day lasts less than
11 hours.
Saturn is the farthest planet that can be
seen by humans without help from a telescope,
and so it has been known to humans for thousands
of years. The ancient Babylonians, Greeks,
Romans, Chinese and Japanese astronomers and
more all had a name for Saturn. The word 'Saturn'
comes from the name of the ancient Roman god
Saturnus, god of wealth and agriculture.
Although ancient astronomers knew about Saturn,
no one knew about its rings. The rings are
not visible without the help of a telescope,
and so it wasn't until the astronomer Galileo
used his telescope to observe Saturn in 1610
that people knew that there was anything different
about it at all. When Galileo saw Saturn's
rings, he didn't know what they could be.
He thought they might be moons, or smaller
planets set beside the main one in the center.
He even described the rings as Saturn's "ears."
It wasn't until later, when stronger telescopes
were made, that astronomers realized that
Saturn was surrounded by wide, flat rings.
Saturn's rings are about 175,000 miles or
282,000 km across, but only about 30 feet
- or 10 meters - thick. They are made of many,
many pieces of ice and rock, ranging from
the size of a grain of sand to the size of
a bus. Scientists believe that the rings may
have formed when comets, asteroids, or even
moons collided or were ripped apart by Saturn's
gravity. As time went on these pieces may
have continued colliding with each other,
smashing into smaller and smaller pieces.
In addition to its rings, many moons and satellites
orbit Saturn. It has at least 62 moons, and
perhaps 100 more smaller bodies also circling
it. Saturn's largest moon, Titan, is the second-largest
moon in the Solar System. Scientists are very
interested in Titan, because it is the only
moon in the solar system known to have a dense
atmosphere: mostly nitrogen with some methane
and hydrogen present. Titan is also the only
celestial body aside from Earth that has ever
been found to have bodies of liquid on its
surface. These liquid bodies are not made
of water, of course - the surface of Titan
is far too cold for liquid water - so the
lakes and seas of Titan are filled with ethane,
methane, and propane.
So far, only four spacecraft have flown by
Saturn. Beginning with Pioneer 11 in 1979
and quickly followed by Voyagers one and two
in the early 1980s, no other missions visited
Saturn for more than 20 years, until the Cassini
spacecraft arrived in 2004 and began orbiting
the planet. Cassini remains there to this
day, sending pictures and information about
Saturn back to Earth. There is no way to know
what new information will be revealed next!
I hope you enjoyed learning about Saturn,
the ringed planet. Goodbye till next time!
