Download The Gas Giant Planets

The Gas Giant Planets
By Patti Hutchison
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Caption: Picture of Saturn from the
Hubble Space Telescope
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Jupiter, Saturn, Uranus, Neptune. These
are the giant gas planets. Scientists think they
are made of small, solid cores. Their interiors
are fluid. Lightweight gases such as hydrogen
and helium make up most of their mass. With
all their satellites and ring systems, they are
very interesting to observe.
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Jupiter is the largest planet. It is the fifth from the sun. The length of its year is about 4330
Earth days. This is how long it takes for Jupiter to make one revolution around the sun. It spins
very fast, however. It takes only about nine Earth hours for Jupiter to make one rotation.
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Jupiter's diameter is eleven times larger than Earth's. In fact, Jupiter is only ten times
smaller than the sun. This giant planet makes up about 70 percent of all the planetary matter in
our solar system.
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Jupiter's atmosphere is made of mostly helium and hydrogen. There are strong winds in its
upper atmosphere. These cause violent storms that rage almost all the time. The Great Red Spot
is actually a giant storm. It has been seen for over 300 years.
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Other interesting features of Jupiter are its moons and ring. Jupiter has 62 moons. Some are
almost as big as planets. One moon, called Io, is the most volcanically active body in the solar
system. Jupiter also has a ring made mostly of dust particles. It is 6400 kilometers wide.
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Saturn is the first planet known to have rings. The rings exist in a system. These rings are
made of pieces of rock and ice. Scientists believe these particles came from shattered comets,
asteroids, or moons. The particle sizes range from microscopic to as large as a house. Saturn
has thousands of rings that are the largest and brightest in the solar system. In addition to the
rings, Saturn has at least 48 moons orbiting it.
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Saturn's orbit takes over 29 Earth years to complete. Like Jupiter, however, it spins quickly
in space. It takes a little over 10 hours to complete one rotation. Also like Jupiter, Saturn's
atmosphere is made of mostly hydrogen and helium. It has violent winds, blowing at over 1100
miles per hour at the equator.
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Uranus is the seventh planet from the sun. Its year is equal to 84 Earth years. Uranus is very
large and made of gas. It has no solid surface. Its atmosphere is made up of helium and
hydrogen. It also contains methane, which gives it its bluish color. Seasons last over 20 years
on Uranus. Scientists believe this is because it is tipped on its side. Like the other gas planets,
it has eleven rings, and it has 27 moons.
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About 60 Earths could fit inside Neptune, the fourth largest planet in the solar system.
Scientists believe it is the windiest planet. Winds blow at over 1200 miles per hour. Large
storms rage above the planet. Once, Neptune had a Great Dark Spot as big as Earth. It was a
storm that blew across the surface at over 700 miles per hour. It has disappeared, but a new
spot is now visible.
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It takes Neptune 165 Earth years to complete one orbit around the sun. It takes 16 Earth
hours to make one rotation. This gas giant has six rings and 13 known moons. One of its
moons, Triton, orbits backward. Nitrogen geysers have been observed on Triton.
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Studying the giant gas planets helps us to learn much about the solar system. We can
study how the solar system was before the planets formed. Some of these planets' moons show
us what the atmosphere was like on Earth before life began. Many questions can be answered.
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