Planet Jupiter Coloring Page: Free PDF Sheet for Kids

Jupiter: The Solar System's Largest Planet

The Storm Older Than Any Living Person

The Great Red Spot has been tracked by astronomers since at least 1830, and some records suggest possible sightings as far back as the 1600s, making it one of the longest-lived storms known anywhere in the solar system. The storm is wide enough to swallow Earth whole, though measurements over the past century show it has been gradually shrinking - from an estimated 25,000 miles across in the late 1800s to roughly 10,000 miles wide today.

Galileo's First Telescope Discovery

In January 1610, Galileo Galilei pointed a homemade telescope at Jupiter and noticed four small points of light that moved position from night to night. He correctly concluded they were moons orbiting Jupiter rather than fixed stars - the first objects ever discovered orbiting a planet other than Earth. Those four moons, now called Io, Europa, Ganymede, and Callisto, are still known today as the Galilean moons in his honor.

A Planet Made Mostly of Gas

Unlike Earth or Mars, Jupiter has no true solid surface to stand on - it is a gas giant composed mainly of hydrogen and helium, the same elements that make up most of the Sun. Scientists believe pressure increases so dramatically toward the planet's core that hydrogen gas is squeezed into a strange liquid metallic state, a form of matter that barely exists naturally anywhere else in the solar system.

The Bands That Wrap Around the Planet

Jupiter's cloud bands, alternating between lighter zones and darker belts, are created by powerful jet-stream winds blowing in opposite directions at different latitudes, some reaching speeds over 300 miles per hour. These bands are constantly shifting and swirling, and the largest storms - including the Great Red Spot - form where bands moving in opposite directions rub against each other, generating enormous rotating weather systems.

The Juno Mission's Close Look

NASA's Juno spacecraft entered orbit around Jupiter on July 4, 2016, and has since sent back the closest photographs ever taken of the planet's swirling poles, revealing cyclone clusters shaped like flower petals that scientists did not expect to find. Juno uses solar panels rather than nuclear power, making it the farthest-from-the-Sun solar-powered spacecraft ever flown, since sunlight at Jupiter's distance is roughly 25 times weaker than at Earth.

Jupiter's Growing Family of Moons

As of recent counts, Jupiter has more than 90 confirmed moons, more than any other planet in the solar system, ranging from Ganymede - larger than the planet Mercury - down to tiny irregular rocks only a few miles across. Astronomers keep discovering more using powerful ground-based telescopes, and the total count has grown substantially just in the past decade as detection technology has improved.

A Day Shorter Than Ten Hours

Despite being the largest planet, Jupiter spins faster than any other, completing a full rotation in just 9 hours and 56 minutes. That rapid spin flattens the planet slightly at its poles and whips its cloud bands into the fast, alternating jet streams that give Jupiter its striped look, since gas at the equator has to travel much farther per rotation than gas nearer the poles, creating strong shearing winds between neighboring bands.