If you’re reading this right around sunset, grab your phone, and take a quick stroll outside.
On the night of December 21st, the planets Jupiter and Saturn – the two largest stars in the solar system – will engage in a “great conjunction,” aligning so closely as to form what has been called the “Christmas Star.”
Though obviously not a star, the two planets will be in such proximity as to make a bright splash of light in the night sky after sunset on Monday.
The occurrence isn’t exceedingly rare, happening once every 20 years or so, but the close range of both Saturn and Jupiter – separated by just 6 arc minutes according to Space – is something that doesn’t happen nearly as often.
“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,” Patrick Hartigan, a professor of physics and astronomy at Rice University, said in a statement.
Hartigan defines the event as a “spectacular sight” and explains that the two planets will remain separated by less than the diameter of a full moon all the way up until Christmas.
Skywatchers, you’re in for a once-in-a-lifetime treat! Jupiter & Saturn are doing a planetary dance that will result in the Great Conjunction on Dec 21, just after sunset. Find out:
When and where to look up
How to photograph the conjunction
— NASA (@NASA) December 20, 2020
Will You Be Able To See the ‘Christmas Star’?
As with many celestial events, certain locations will be better for observing the Christmas Star.
But there’s good news for everyone looking to catch a glimpse.
“Though the best viewing conditions will be near the equator, the event will be observable anywhere on Earth, weather-permitting,” a Rice News report reads.
“Hartigan said the planetary duo will appear low in the western sky for about an hour after sunset each evening.”
But CNN notes that waiting too long after sunset could create other observational issues.
“If you’re in New York or London, or along those latitudes, try to spot the conjunction right after sunset,” they advise. “Waiting an hour after the sun sets will only put the planets closer to the horizon, making them more difficult to spot.”
Are you as excited as we are about the alignment of Saturn and Jupiter?!?
— The Weather Channel (@weatherchannel) December 21, 2020
Is It The Star Of Bethlehem?
Many wonder whether the great conjunction could be an explanation for the Star of Bethlehem.
Professor David Hughes, an astronomer from the University of Sheffield, says that a triple conjunction – three occurrences in a relatively short period of time – could be behind it.
Space also notes this possibility:
The first conjunction (on May 29 — visible “in the east” before sunrise) presumably started the Magi on their way to Bethlehem from the Far East. The middle conjunction (September 30) may have strengthened their resolve in the purpose of their journey, while the third and final conjunction (Dec. 5) occurred just as they arrived in Judea to meet with King Herod, who sent them on to Bethlehem to “go and search diligently for the young child.”
TOMORROW Jupiter and Saturn will be at their closest separation in the sky since 1623 at 0.1° apart. Here’s an animation showing exactly how close that is relative to a familiar object, the Moon! (Moon ONLY added to illustrate the scale) #GreatConjunction2020 pic.twitter.com/2mvdl6KjmI
— Dr. James O’Donoghue (@physicsJ) December 20, 2020
Another theory for the Star of Bethlehem has been a very bright comet, though these celestial objects at the time were typically viewed as a bad omen.
President Trump mentioned the biblical star at a Christmas tree-lighting ceremony recently.
“More than two thousand years ago, a brilliant star shown in the east,” he said. “Wise men traveled far and they came and they stood under the star where they found the Holy Family, in Bethlehem.”
“As the Bible tells us, when the wise men had come into the house, they saw the young child with Mary His mother, and fell down and worshipped Him,” the president continued.
“Christians give thanks that the Son of God came into the world to save humanity. Jesus Christ inspires us to love one another with hearts full of generosity and grace.”
The Lowell Observatory in Flagstaff, Arizona, announced they will host a program beginning at 7 p.m. ET, showcasing live views of the great conjunction through its telescopes.