Jupiter and Saturn Come Together

In this composite image, seventh-grade science enthusiast Lucy Nement looks at the southwestern corner of the sky with Quade.

Look to the sky on December 21 to witness a rare celestial event. On this winter solstice day, with the shortest dawn-to-dusk period in 2020 in the Northern Hemisphere, Jupiter and Saturn will align in the southwestern sky. This rare planetary arrangement has been nicknamed the “Christmas Star” and the “Great Conjunction” (union). 

Every night in December, mega planets Jupiter and Saturn will appear to be closer together. Although they are more than 400 million miles apart, on the 21st, their location in space will make them appear inseparable to the naked eye. The last conjunction occurred in 2000, but it was difficult to see. There also was one in 1623, when the famed Italian astronomer Galileo Galilei was alive.

“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,” Rice University astronomer Patrick Hartigan told The Guardian. The two planets will not be this close again until 2080.

“To us, the 1/10th-degree difference in alignment between the solar system’s two largest planets will be indistinguishable,” said Heather Michel, a middle-school science teacher in Bend, Oregon. “Jupiter and Saturn are often the night’s brightest celestial bodies independent of each other. It will be amazing to see the conjunction of the two planets illuminate the night sky.” 


This drawing shows the alignment of Jupiter and Saturn, which will occur on December 21. 


This rare planetary phenomenon is being compared to the Star of Bethlehem, which coincided with the birth of Jesus as depicted in the Gospel of Matthew. Many Christians believe that the star was a miraculous sign drawing the Three Wise Men, or “Magi” to Bethlehem. Astronomers think that the celestial phenomenon depicted in the Bible may also have been a Great Conjunction. 

On December 21, about 45 minutes after sunset, look to the southwest to find the Moon. The two planets will be above it. Jupiter is already the second-brightest object in space, so together, Jupiter and Saturn will form the brightest object in the night sky. 


Top photo: © Can Stock Photo / vovan13; composite: Kendra Krishnan; illustration: Carrie Gugger