The Christmas Star will be visible on December 21.
On Dec. 21, humans can witness something not seen in nearly 800 years. Jupiter and Saturn will line up to create what is known as the “Christmas Star” or “Star of Bethlehem.”
These two planets haven’t appeared this (relatively) close together from Earth’s vantage point since the Middle Ages.
“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 be to one another,” Patrick Hartigan, astronomer at Rice University, told Forbes. “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.”
Stargazers in the northern hemisphere should turn their heads and telescopes to the southwest portion of the sky about 45 minutes after sunset to see the planets align Dec. 21. However, reportedly sightings can be seen throughout that entire week.