NASA

Why ‘Christmas Star' Sighting is Especially Historic and Fascinating

It will be the first time such a close conjunction has been observable since 1226, according to EarthSky

NBCUniversal Media, LLC

Twenty-twenty has already brought several firsts for much of the world, but as the year comes to a close, a once-in-a-lifetime sight will appear in the night sky just in time for the holidays.

It's called the "Great Conjunction," or the moment when Jupiter and Saturn appear at their closest – "a tenth of a degree apart" – according to Chicago's Adler Planetarium.

The event is set to take place on Dec. 21, which also marks the Winter Solstice, bringing the shortest amount of daylight and the longest night. 

Though conjunctions happen roughly every 20 years, this one will be particularly close.

It will be the first Jupiter-Saturn conjunction since 2000, but the first time the planets will have been so close since 1623. It will also be the first time such a close conjunction has been observable since 1226, according to EarthSky.

Still, according to NASA, "while the two gas giants may appear close, in reality they are hundreds of millions of miles apart."

The event has been dubbed the "Christmas star," because some astronomers have theorized the “Star of Bethlehem” could have been a rare conjunction involving both Jupiter and Saturn.

"This will still be quite a striking sight, but you will need to look fast as both planets will set shortly after sunset," NASA's website says.  

Those looking to see the star will want to look above the southwestern or western horizon after sunset, experts say.

Don't worry if you can't catch it on Dec. 21.

According to the Adler Planetarium, the planets can be seen as early as Dec. 16 and 17, but the "real show" takes place "the evenings of the 20th through the 22nd."

Contact Us