Jupiter, Moon Align in Christmas Night Sky; Jupiter's Red Spot Visible to North American Observers

On Tuesday night, in the east-southeast sky, Jupiter and a nearly full moon will align for a couple of hours, replacing Santa and his sleigh full of gifts.

According to Space.com, the largest planet in our solar system and the moon appeared the closest together in the late afternoon or early evening around 6:25 p.m. EST. Jupiter appeared about one-half degree from the limb of the moon, Space.com reported.

The two will slowly move apart as Tuesday night wears on into early Wednesday morning. However, Jupiter will remain high in the east-southeast and won't set in the west until about 5 a.m. PST. It is currently floating in front of the constellation Taurus (the Bull), Space.com reported.

Three of Jupiter's moons, Ganymede, Callisto and Europa, will also be visible throughout the night. According to Space.com, Ganymede (on one side of Jupiter) and Europa (on the other side) will steadily move away from the planet. Around 7:15 p.m. EST, a fourth moon, Io, took over Europa's place next to Jupiter. Then at 11:40 p.m. EST, Io will pass Europa and become easier to spot.

RedOrbit also reported that Jupiter's Great Red Spot-an enormous swirling storm that's about twice as wide as Earth-will be visible to observers on Earth. Glenn Orton from NASA's JPL told RedOrbit that "the Red Spot is shrinking," and that "As the size contracts, the spin rate increases."

John Rogers, from the British Astronomical Association's Jupiter Section, confirmed that the Red Spot's spin rate is getting faster. In a statement with NASA, Rogers said, "The trend of decreasing rotation period has been consistent at least since Voyager visited Jupiter in 1979." He added that the spot has also been changing shape and that it is now circular.

"Perhaps the Red Spot will continue to shrink and eventually disappear," he surmised. "Or perhaps it will be rejuvenated if some new storm arises to reinforce it."

Observers in North America should not need a telescope to catch a glimpse of Jupiter's Red Spot, RedOrbit reported.