“Christmas Star” explained: where did the rare planetary alignment get its name from?

In the early evening of this month, Jupiter and Saturn are almost unmissable. The brilliant pair of gas giants are sitting so close to each other in our night sky that it seems they can reach out and touch each other. If you keep paying attention, it will seem to happen. The planets will unite to form a single bright spot like a double planet. It will be the first time this has happened since the Middle Ages.

You will be able to see this splendid formation on the night of the winter solstice, December 21st. The event is called a great conjunction, but it is also referred to as a “Christmas star”. A conjunction, by the way, is the alignment or close passage of two planets from our perspective on Earth. Unlike a supermoon, the “great” of a great conjunction is an earned superlative. It’s a rarity, and this one will be closest from 1226, according to Rice University astronomer Patrick Hartigan.

So why is it called a “Christmas star”?

Due to the arrival of the event near the holiday season, many refer to the formation as a “Christmas star”. However, Jamie Carter a Forbes says there is more to the name than mere closeness. He notes that some, including the famous astronomer Johannes Kepler, claim that the star of Bethlehem as seen by the three sages in the Christian Bible may have been a very rare triple conjunction between Venus, Saturn and Jupiter.

However, there is a lot of debate as to what the Magi actually saw. Some theories about the star of Bethlehem imply a conjunction other than this triple conjunction, while others cite a comet, Uranus or even a supernova as the cause of the biblical star. No matter what it was, this year’s lineup and its timing have already evoked that “Christmas Star” labeled story that was launched.

Our perspective on Earth will make this an extraordinary sight, but the planets are still an extraordinarily long distance in the solar system.

A conjunction between the gas giants happens about once every 20 years. While it’s not always as visible in the night sky, it’s rarely seen with planets as close together as they will be this year. You will be able to spot them right after sunset in the southwestern sky if you are looking from the US. (However, this conjunction will be visible worldwide as long as you have clear skies.) They will be low in the sky and will not be around long before they fall below the horizon.

Don’t miss the amazing sight, because you won’t be able to see one this close until 2080. However, it won’t be a “Christmas star”. That conjunction will take place in May.