• From most places around the world on this holiday night - December 25, 2012 - the moon and dazzling planet Jupiter appear close together as soon as night falls. If your skies are clear, you can't miss seeing Jupiter as the brilliant starlike object by the moon. The bright

star nearby is Aldebaran. The moon and Jupiter appear low in the east at dusk. They climb upward and westward as night deepens - and finally set in the west before the onset of morning dawn. Watch for the 2012 Christmas conjunction of the moon and Jupiter! If you're celebrating on this day - or if you're not - it's a great way to end the day.
• If you live in Brazil or southern Africa, you may be able to see the moon occult - cover over - Jupiter sometime tonight. Click here for more information on tonight's lunar occultation of Jupiter.
• New telescope or binoculars for Christmas 2012? Turn them on Jupiter. Observing Jupiter in the bright light of tonight's moon won't give you the best view. But it'll give you something to point at in tonight's sky as you set up your new equipment and learn to use it. And even in bright moonlight, you should be able to see Jupiter's cloud bands and four brightest moons, called the Galilean satellites.
• The four major moons are called the Galilean moons. In their outward order from Jupiter, these moons are Io, Europa, Ganymede and Callisto. Amazingly enough,

the first three moons - Io, Europa and Ganymede - are locked into a 1:2:4 orbital resonance. For every one time that Ganymede revolves around Jupiter, Europa revolves around Jupiter 2 times and Io 4 times. Callisto is expected to join this orbital resonance in a few hundred million years. Io, the innermost Galilean moon, goes around Jupiter in 1.769 Earth-days. Given this information, you should be able to fig

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