As Jupiter and Saturn will rendezvous just a few days before Christmas, forming what will look like a single bright object in the sky, the 2020 great conjunction is sometimes also called the "Christmas star" or "Bethlehem star."
In fact, some scholars have theorized that the original Christmas star, known as the Star of Bethlehem, might also have been a great conjunction. According to Christian lore, a bright light in the sky led the Three Wise Men to the location of Jesus's birth. Other theories aiming to explain this biblical phenomenon include a supernova explosion and a comet.
Some media outlets have also referred to the phenomenon as "kissing stars" or "double planets."
The December 21, 2020 conjunction will be the closest great conjunction since July 16, 1623. At the great conjunction of 1623, Jupiter and Saturn were slightly less than 0.1 degrees apart. However, this event would have been difficult-although not impossible-to observe since the two planets were near the Sun.
The last time that the two planets were easily observable when separated by less than 0.1 degrees was almost 800 years ago, during the great conjunction of 1226.