What Is the Christmas Star? Iconic Planetary Alignment Will Appear in December After 800 Years

After a year of firsts and wild experiences, 2020 will end with a sighting of the "Christmas Star," a planetary alignment that hasn't been seen for 800 years. Toward the end of December, stargazers can expect to see an incomparable, glowing spot in the night sky.

On December 21 the Christmas star will be visible, though it isn't actually a star at all. The guiding point, which is also called the Star of Bethlehem, is actually two plants in a line. Jupiter and Saturn will be so close to earth, and aligned in orbit, that they'll appear to create an intensely bright "star."

Jupiter and Saturn do align some years, though what's uncommon in 2020 is how close they'll appear to Earth. As they align to create a "double planet," as Forbes called the sight, it will be the first time since the middle ages that the alignment has been this visible.

Astronomer Patrick Hartigan explained to Forbes. "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," he said. "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."

This artist's conceptual drawing released June 13, 2002, depicts a Jupiter-mass planet orbiting the star, 55 Cancri, about 41 light years from Earth. Lynette Cook/NASA/Getty Images/Getty

It won't take quite as long for this to happen again, though. Another Christmas Star is expected to appear in the night sky in 2080. It won't even be a "Christmas" star then, though, as the alignment is expected in May, sixty years from now.

Unlike some spectacular celestial occurrences, those who wish to witness the 2020 Christmas Star won't have to stay up all night. Depending on where you are, you can expect to see the phenomenon 45 minutes after the sun sets. The Christmas Star should be visible with your naked eye when looking to the southwest. Of course, if it's a cloudy night you may be out of luck.

For Christians observing the holiday, the Christmas Star may hold even more meaning. The planet's alignment may be featured in the birth story of Jesus as the three wise men followed the "Star of Bethlehem" to welcome the Son of God into the world on Christmas Eve. It's widely theorized that the star the wise men followed in the biblical text may have really been a similar planetary alignment of Jupiter and Saturn. Inverse outlined the theory in 2016.