There’s a bright shiner lighting up the Butler heavens all night long on these cold November evenings. Jupiter, the largest planet in the solar system, is still overwhelming any other star or planet in the night sky.

Only the moon is brighter in the sky, but this week it’s absent, leaving Jupiter in full command.

The reason Jupiter is so bright is twofold. First off, Earth and Jupiter are still relatively close to each other right now, separated by less than 373 million miles. Late last month they were separated by less than 370 million miles, their closest face off for 2011 in what astronomers call opposition.

Another reason Jupiter is extremely dazzling is that Jupiter is one monster of a planet, 88,000 miles in diameter, more than ten times the diameter of Earth. In fact, if Jupiter was a hollow sphere you easily fit more than 1,300 Earths inside it!

With even a small telescope or a decent pair of binoculars you can resolve the disk of the planet and maybe even see some of its cloud bands, especially the two dark ones on either side of the equator.

What easily catches your eye, though, are up to four small starlike objects that accompany Jupiter. They’re either to the left or right of Jupiter, and they’re constantly on the move from night to night. These are Jupiter’s four brightest and biggest moons that obediently orbit Jupiter in periods of two to 17 days, all within two million miles of the Jovian planet.

The moons Io, Europa, Ganymede and Callisto are constantly changing position relative to Jupiter and each other. Every night you see them they’re arranged differently.

Some nights you can’t see all four because one or more moons may be temporarily hiding behind the planet or passing in front of it, camouflaged by Jupiter’s brightly sunlit clouds.

What I think is really cool is when one of the moons is really close to the limb of Jupiter so you can see it slip in back of or in front of the planet over the course of several hours. With a medium to large telescope you can sometimes see the shadow of the moon that happens to be crossing in front of Jupiter. It’s just a tiny black dot, but it can be really tricky to see.

As I told you last week, you need to look at Jupiter through your telescope for continual stretches of at least 10 minutes to get used to the light levels through your scope. Quick glances just don’t cut it most of the time.

There are many good sources on the Internet that keep you up to date with the arrangement of Jupiter’s moons from night to night. The one I use is from Sky and Telescope Magazine. I have a diagram of moon positions around Jupiter for the week to get you started.

These four brightest moons of Jupiter are referred to as the Galilean moons because of the great astronomer Galileo, who saw them for the first time in 1610.

Using his crude telescope to observe the moons, Galileo concluded that they were orbiting Jupiter from their night to night position changes.

He used these observations to help plead his case that the Earth and other planets like Jupiter were actually orbiting around the sun instead of the much held belief in an Earth-centered universe.

Unfortunately, he wasn’t able to persuade the Catholic Church or the government of his theory and was put under house arrest.

Two of the Galilean moons, Io and Europa, are among the most interesting bodies in our solar system.

Io, Jupiter’s closest moon, has constant volcanic activity because of the strong gravitational tides caused by Jupiter. The 2,200-mile wide moon, about as big as Earth’s moon, is under constant torture as it’s constantly be pulled and stretched, which generates interior heat and a molten core resulting in volcanic eruptions.

Europa, Jupiter’s smallest Galilean moon, is less than 2,000 miles in diameter and is one of the leading candidates for life beyond Earth in our solar system. Its surface is the smoothest in our solar system as it’s completely covered by a fractured sheet of ice. Because of the same strong tidal forces, it may be warm enough in Europa’s interior that a slushy ocean of liquid water may be underneath, and where there’s liquid water there may be life as we know it. Stay tuned!

Follow the dancing moons of Jupiter this week and have great Thanksgiving.

Celestial hugging

Early Tuesday, about 5 to 6 a.m., look for the thin waning crescent moon. Just to the left of the thin moon you’ll see the bright star Spica, and just to left of Spica, the planet Saturn. It should be quite a site!

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Pennsylvania Starwatch,” available at bookstores and at www.lynchandthestars.com.