Transcript Saturn

Saturn
sixth planet from the sun
In Roman mythology, Saturn is the
god of agriculture and time. Saturn
is the root of the English word
"Saturday"
They had a total of six
children, but Cronus had a bad
habit of eating his newborn
children, to prevent them from
one day overthrowing him as
king of the gods. Finally, at the
birth of her last child, Zeus,
Rhea tricked him into
swallowing a rock instead. Zeus
then beat his father, with the
help of his brothers and
sisters. The Romans adopted
Cronus as the god Saturn.
In Greek
mythology,
Cronus was the
son of Uranus
and Gaea. He lead
his brothers and
sisters, the
Titans, in a revolt
against their
father and
became the king
of the gods. He
married the Titan
Rhea.
History of Saturn Observation
The oldest
written records
documenting
Saturn are
attributed to
the Assyrians.
Around 700 B.C.,
they described
the ringed
planet as a
sparkle in the
night and named
it "Star of
Ninib."
Like the Greeks, in
Roman mythology Saturn
was also the god of
agriculture. It was in his
honor that in December
the Saturnalia festival
was celebrated, a sevenday affair that became
ancient Rome's most
popular festivity.
At first Galileo assumed
Saturn was a group of three
close-knit planets, with two
smaller ones on each side of
a bigger planet. Two years
later, he noticed that the
two smaller planets had
vanished and Saturn was now
all by itself. We know now
that the rings seem to
disappear as our view of the
ring plane shifts. A couple
of years later, Galileo's
observations became even
more confusing when the
rings reappeared, in their
places next to Saturn.
Confusion reigned until Christiaan Huygens, a
Dutch astronomer, developed the concept of a
planetary ring system in 1659. Using an
improved telescope - one that could magnify
images by 50 times -- Huygens theorized the
rings to be solid, thin and flat
In 1676, Giovanni Cassini, an
Italian astronomer who
eventually became a French
citizen, was able to see the
biggest gap within the ring
system, now known as the
Cassini Division or the Cassini
Gap. Cassini and Huygens also
discovered moons around the
ringed planet, and the known
number of satellites orbiting
Saturn has been growing ever
since.
Finding Saturn
Saturn is the sixth planet from the Sun and the second largest:
Saturn is about 74,898
miles (120,536 km) in
diameter (at the equator
at the cloud tops). This is
about 9.4 times the
diameter of the Earth.
764 Earths could fit
inside a hollowed-out
Saturn.
Each day on Saturn takes 10.2 Earth
hours. A year on Saturn takes 29.46
Earth years; it takes 29.46 Earth
years for Saturn to orbit the sun
once.
Saturn is 9.539 AU, on
average, from the sun,
about 9 and a half times as
far from the Sun as the
Earth is.
Saturn is about 97% Hydrogen gas, about
3% helium gas and about 0.05% methane,
plus ammonia.
Saturn’s Atmosphere
There are three
clouddecks on Saturn,
and each one is composed
of different molecules.
There is a clouddeck of
ammonia clouds, a
clouddeck of ammonia
hydrosulfide clouds, and
a clouddeck of water
clouds (H2O).
.
Motions in the
cloud patterns
indicate that, like
Jupiter, the basic
weather of Saturn
can be described
as a striped
pattern of winds.
The clouds of Saturn are much less
colorful than those of Jupiter. This
is because the composition of
Saturn's atmosphere includes more
sulfur. This adds to Saturn's overall
yellow appearance
Saturn is the most oblate (flattened) planet in our Solar
System. It has a equatorial diameter of 74,898 miles
(120,536 km) (at the cloud tops) and a polar diameter of
67,560 miles (108,728 km). This is a difference of about
10%. Saturn's flattened shape is probably caused by its fast
rotation and its gaseous composition.
Near the equator,
tremendous winds blow at
1,100 mph (500 meters per
second) toward the east.
The clouds in the
atmosphere are cold, thick
and uniform in shape.
Saturn is a gaseous planet with a rocky core, a
liquid metallic hydrogen layer above the core, and
a molecular hydrogen layer above that. The hot,
heavy, rocky core has a radius possibly three
times the radius of the Earth.
Saturn has a strong magnetic field (less than Jupiter's,
but still very strong). Saturn's magnetic field is probably
generated by electrical current in conductive layers near
the quickly-rotating planet's core. Because of this strong
magnetic field, there are abundant auroras on Saturn and
radios emissions from it.
Saturn radiates 79% more energy than it receives from
the Sun, probably heat from its hot core.
The mean temperature on Saturn (at the
cloud tops) is 88 K (-185° C; -290° F).
Saturn is the only planet in our Solar
System that is less dense than
water. Saturn would float if there
were a body of water large enough!
Saturn's mass is
about 5.69 x 1026
kg. Although this
is 95 times the
mass of the
Earth, the gravity
on Saturn is only
1.08 times the
gravity on Earth.
A 100 pound
person would only
weigh 108 pounds
on Saturn.
RINGS
Saturn's bright rings are made of ice chunks (and
some rocks) that range in size from the size of a
fingernail to the size of a car. Although the rings are
extremely wide (almost 185,000 miles = 300,000 km in
diameter), they are very thin (about 0.6 miles = 1 km
thick).
SPACECRAFT VISITS
Saturn has been visited by Pioneer 11 (in
1979) and by Voyager 1 and Voyager 2.
Cassini, a spacecraft named for the
divisions in Saturn's rings, is on the way
and will arrive in 2004
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