Week of Jan. 5-11, 2014

What a great way to begin the new year. Jupiter is back in our night sky, and no one could be happier.

Everyone talks about the glistening crescent of Venus, ruddy red hue of Mars or the stunning rings of Saturn, but for my money, Jupiter's where it's at. And, as luck would have it, Jupiter reaches its opposition point on Jan. 5, when it appears opposite the sun in our sky. In other words, as the sun sets in the southwest, Jupiter rises in the northeast and shines brightly in our sky all night long.

Opposition also means that the planet lies closest to Earth and, therefore, appears larger and brighter than at any other time of its orbit. So Jupiter, which is always impressive to view through a small telescope, will be especially impressive to view right now. In fact, it will be quite a sight for the next month or two.

Jupiter is always one of my favorites because it's one of the few celestial bodies that actually seems to do something. Here's a world that's 11 times the diameter of Earth, yet it rotates on its axis once every ten hours or so. This means that its Earth-facing side changes completely in just five hours and, with patience, sky watchers with a small telescope can easily watch its pastel cloud bands and, sometimes, its Great Red Spot spin completely around in just one long evening of stargazing.

Equally amazing is knowing that Jupiter is made entirely of gas; there is absolutely no surface on which to stand. Hypothetical astronauts trying to "land" on the planet would just sink deeper and deeper into its murky atmosphere until they became crushed beyond recognition by its tremendous weight.

Perhaps the most enjoyable part of watching this planet is keeping up with the antics of its four largest moons. These are known as the Galilean satellites — Io, Europa, Ganymede and Callisto — because it was the Italian astronomer Galileo who discovered them and their movements some four centuries ago.

These moons do-si-do around the Jovian disk from night to night, sometimes vanishing behind, or slipping in front of, Jupiter, and sometimes they even cast their shadows onto the giant planet's cloud tops and provide endless entertainment for the backyard astronomer. And sometimes, if two moons are passing one another or approaching or receding from the planet's disk, a sharp-eyed observer can see their movements in only a few minutes.

Much of the fun of watching these moons is knowing which is which. You can identify them by visiting www.skyandtelescope.com/observing/objects/javascript/jupiter, where you can type in the date and time and receive a graphic representation of their positions. And to learn more about these incredible moons and their amazing parent world, be sure to check out: www.nineplanets.org/jupiter.html

Now that Jupiter's back in our early evening sky, try aiming your telescope in its direction, or contact your local astronomy club to learn when they'll be hosting their next free "star party" so you can get a close-up look at the exciting Giant Planet and its exciting family of moons.

It's definitely going to be a fun winter of Jupiter-gazing!

Visit Dennis Mammana at www.dennismammana.com. To read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.