Jupiter, the fifth planet from the Sun, is the largest in our solar system, measuring 44,423 miles. This is 11 times larger than Earth and twice as large as all the planets combined. It looks like a striped ball in the sky. It is a gaseous planet and does not have a solid surface; however, the gas becomes denser as it nears the center of the planet and turns into liquid. The gas composition of the planet is 90% hydrogen and 10% helium as well as other trace gases. We can see the ammonia clouds encircling the planet from outer space.
Although it is the fourth brightest object in the sky, Jupiter’s lack of a solid surface causes it to change shapes. It rotates faster than any other planet in the solar system, resulting in bulging at the equator and flattening at the poles. The planet also has rings like Saturn that can only be seen in the back light of the sun and are thought to be made of dust from meteor collisions with the four largest moons.
The colored stripes around the planet occur because of the high winds blowing in opposite directions, east to west, on nearby bands. Storms continually rage on the planet. The Great Red Spot on the planet is actually a storm that scientists have observed for 300 years. Three Earths can fit in the spot. This gives an idea of the vastness of this planet.
Jupiter is not a very hospitable planet to visit because of the varying temperatures. According to NASA’s website, temperature readings at the top of the clouds are approximately -230 degrees F, or -145 degrees C. The temperature increases below its clouds, reaching temperatures of 70 degrees F, or 21 degrees C. Jupiter’s temperature changes again as it nears the core, approximately 43,000 degrees F, or 24,000 degrees C. This is even hotter than the Sun’s surface.
Science on a Sphere describes Jupiter as “its own little solar system” because of the 63 moons that circle the planet. That is more moons than any other planet in the solar system. Four of the moonsIo, Europa, Ganymede, and Callistoare the size of planets. Scientists discover 23 more moons in 2003. The reason for the large number of moons is the result of the strong gravitational pull and the magnetic field of the planet.
Jupiter gets its name from the King of the Gods, the Roman equivalent of the Greek god Zeus. He is the patron of the Roman state and the brother and husband of Juno. The planet is discovered in 1610 by Galileo when he discovered its moons through his telescope.
Science on a Sphere
World Book of NASA Jupiter