Photo of Jupiter

That was a little walk! We are now entering the part of our Solar System where the planets are made of gas.

The first planet of this type is named for the head of all the gods in Greek mythology, Jupiter.  It is the largest of all the immediate planets, in fact, it is twice as massive of all the planets combined.  Eleven Earths could fit across Jupiter’s equator.  Jupiter orbits about 484 million miles (778 million kilometers) or 5.2 Astronomical Units (AU) from our Sun.

Jupiter rotates once about every 10 hours (a Jovian day) but takes about 12 Earth years to complete one orbit of the Sun (a Jovian year).  Jupiter’s atmosphere is made up mostly of hydrogen (H2) and helium (He). Jupiter has more than 75 moons.  Jupiter’s Great Red Spot is a gigantic storm that’s about twice the size of Earth and has raged for over a century.  Jupiter’s four largest moons—Io, Europa, Ganymede, and Callisto—were first observed by astronomer Galileo Galilei in 1610 using an early version of the telescope. They led him to proclaim that the Sun was the center of the solar system.

Figure this:  Wonder what you would weigh if you could stand on Jupiter? Multiply your weight by 2.34.

Now let’s move on to the next. Get ready to walk.