Download the gas giants

Name:
Date:
The Gas Giant Planets
By Patti Hutchison
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.
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. 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.
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.
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.
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.
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.
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.
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.
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.
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.
Questions
1. What is the largest planet?
A. Saturn
B. Jupiter
C. Uranus
2. What is the Great Red Spot on Jupiter?
A. a crater
B. a giant storm
C. a nitrogen geyser
3. What are Saturn's rings made of?
4. How many Earth years does it take Saturn to complete one orbit around the sun?
A. 70
B. 29
C. 4330
5. What gas gives Uranus a bluish color?
A. methane
B. hydrogen
C. oxygen
6. What was Neptune's Great Dark Spot?
If you could study one of the gas giant planets up close, which one would you choose? Tell why
you chose this one. (3-5 sentences)
Write a paragraph comparing the lengths of the orbits of all the gas giant planets. (5-7 sentences)