Exploring The Planets: Jupiter

New Horizons spacecraft took this collection of images of Jupiter and Io in 2007. Io is a volcanic moon that revolves around

Jupiter. Photo from: NASA.

Jupiter is the largest of the eight planets in our solar system and the fifth planet from the sun. It

is bigger than all the other planets put together. Jupiter travels around the sun at an average

distance of about 483 million miles.

Jupiter was named for the ruler of the ancient Roman gods. He was the equivalent of the

ancient Greek god Zeus. The ancient Romans did not know how large the planet was. The

name turned out to be fitting, though.

Jupiter is also one of the brightest objects in the night sky. Even a small telescope can reveal

its multicolored stripes. These are in fact bands of clouds being pushed around the planet by

strong winds. Jupiter is a world of complex weather patterns. Its most prominent feature is an

orange-red oval called the Great Red Spot. This spot is actually a long-lasting storm system

that is bigger across than Earth.

By Encyclopaedia Britannica, adapted by Newsela staff on 08.28.17

Word Count 691

Level 800L

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Physical Features

Jupiter is one of the four outer planets, along with Saturn, Uranus and Neptune. They are

much farther from the sun than Earth and the other inner planets are. Jupiter lies between the

main asteroid belt and Saturn. Like the other outer planets, it is much larger and less dense

than Earth.

Jupiter is so huge that it could contain more than 1,000 Earths. The distance through its center

is about 89,000 miles. Jupiter is a kind of planet called a gas giant. It consists almost entirely

of gases, mainly hydrogen and helium. The planet has no solid surface. Photographs of

Jupiter actually show its layers of clouds, not a surface. These clouds appear as colored spots

and bright and dark stripes.

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Deep inside Jupiter is an area of hot, thick liquid. The planet’s center may reach temperatures

of 45,000 degrees Fahrenheit. Surrounding the planet is a system of thin rings, which consist

of tiny rocks and dust. They are much smaller and dimmer than Saturn’s rings.

More than 60 moons orbit Jupiter. Most of them are very small. However, Jupiter has four very

large moons, named Io, Europa, Callisto and Ganymede. Ganymede is larger than the planet

Mercury. Scientists believe that Europa, Callisto and Ganymede may have water ice beneath

their surfaces.

Orbit And Spin

A year is the amount of time it takes a planet to make one full revolution around the sun. Earth

takes just over 365 days to make a full trip, so that is the length of a year on Earth. A year on

Jupiter lasts about 12 Earth years. That is because Jupiter is farther from the sun and takes

longer to travel around it.

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Jupiter also spins rapidly about its center. A single day is equal to the time it takes a planet to

make a full rotation. That is one complete spin on the planet's axis. Earth takes 24 hours to

make one full rotation. Jupiter spins much faster, taking only 10 hours to complete one

rotation. That is how long a day lasts on Jupiter.

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Observations And Exploration

People have observed Jupiter from Earth since ancient times. Scientists sent the first

unmanned spacecraft to the planet in the 1970s. The spacecraft flew by the planet and

collected information about it.

Later, the unmanned U.S. Galileo spacecraft orbited Jupiter. In 1995, it dropped an object

called a probe toward the planet. The probe sailed through the upper layers of Jupiter’s gases

and measured their properties. It was the first man-made object to make contact with a gas

giant.

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