How wonderful it is to see the sky on our many dark nights and to consider that each object in the sky is special in its own way.


For August, our special object is Jupiter, which commands the southern night sky as king! Jupiter is the brightest object in the south, just east of the teapot of Sagittarius.


Sagittarius is part of the zodiac and is an archer in legends. But a teapot shape is recognizable as part of Sagittarius and Jupiter is to its left.


Jupiter has many wonderful features:


  • Jupiter is huge. It is 88,850 miles in diameter, 11.2 times the diameter of Earth, which is 7927 miles in diameter. If Jupiter were an empty sphere, it could contain over 1300 Earths.


  • The yellow and orange stripes on Jupiter represent ongoing storms, spinning in different directions from the ones spinning above or below, yet not destroying the storms above and below.


  • A famous storm on Jupiter is the Great Red Spot, which Galileo discovered over 300 years ago. It is twice the diameter of Earth and continues as a storm as the years pass. The mechanics of the Great Red Spot are not completely understood.


  • Jupiter has a large donut of radiation surrounding it. Its power was not recognized until Pioneer 10 flew by in 1976. Part of that probe’s mission was destroyed by Jupiter’s intense radiation. Jupiter has the “harshest radiation environment in the solar system,” according to NASA.


  • Jupiter, as massive and huge as it is, spins once every 9.8 hours. Remember that Earth takes 24 hours for just one spin.


  • Jupiter chugs along rather slowly in its journey around the sun. Its orbital speed is 8 miles per second. It takes 11.9 years to orbit the sun. Earth, by contrast, is pretty speedy—going 19 miles per second in its orbit and taking only one year to orbit the sun.


Jupiter has more moons than any other planet. More are discovered each year so a solid number can’t be given. There are four special moons called the Galilean moons, which are the largest and rather mysterious because they are so different from one another.


The closest is Io, the name of a person that Jupiter was romantically attached to, according to legend. The moon is known for its sulfur volcanoes which spit sulfur into space for 160 miles or so. In photos, the planet looks like a not-so-great pizza. The sulfur is heated under the surface because of the gravitational flexing caused by nearby Jupiter. There is always a sulfur volcano erupting somewhere on Io.


The next amazing moon is Europa, which is covered with ice, probably water ice. This is strange! How can it be that Io has much sulfur and Europa is covered in ice, with probably liquid water underneath (and maybe some form of life)?


The next two moons, Ganemede and Callisto, are much like our moon, covered in craters.


Jupiter and its four moons are extremely fascinating. I hope you can see all of this.