The shortest day of what has felt like the longest year will provide something to celebrate, millions of miles away.
Saturn and Jupiter are getting together to put on a show not specifically seen in 800 years, creating a “conjunction” known widely as the “Christmas Star.”
On Monday—also the winter solstice—just after sunset, the solar system’s two largest planets will appear closer together than they have in 800 years, creating the look of a double planet.
“You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” said Henry Throop, an astronomer in the Planetary Science Division at NASA Headquarters in Washington.
“From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on Dec. 21.”
Just about everyone around the world—given their skies are clear—will be able to see the conjunction low in the western-southwestern sky for about an hour after sunset.
“Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to one another,” said Rice University astronomer and professor of physics and astronomy Patrick Hartigan in a statement appearing in a CNN story.
“You’d have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky.”
According to NASA, it’s been nearly 400 years since the planets passed this close to each other in the sky, and nearly 800 years since the alignment of Saturn and Jupiter occurred at night.