The Jupiter-Saturn Christmas Star: 2020’s Great Conjunction and What to Watch For
Quick Reference: The Christmas Star (Great Conjunction)
- Event: Jupiter and Saturn appearing very close together in the sky (a great conjunction).
- Famous example: December 21, 2020. Closest pairing in 397 years.
- Frequency: Jupiter and Saturn align about every 20 years, but most pairings are not nearly as close.
- Next near-equivalent: March 15, 2080.
- How to see one: shortly after sunset, low in the western sky. No telescope needed.
- Nickname: Christmas Star (when the conjunction falls near December 25).
On December 21, 2020, the planets Jupiter and Saturn appeared closer together in the sky than at any time since 1623. Many called it the modern Christmas Star, both for the December date and for its likely connection to the Star of Bethlehem story. Here is what happened, what made it special, and what to watch for in the next conjunctions.
What Happened in 2020
Jupiter and Saturn align in the sky roughly every 20 years. The 2020 alignment was unusually close: only 0.1 degree apart, or about one-fifth the width of the full moon. To the naked eye the two planets nearly merged into a single bright point. The closest such alignment had been March 4, 1226. The closest before that was 1623.
Why the Connection to Bethlehem
The 2020 conjunction revived discussion of the Star of Bethlehem from Matthew’s Gospel. Johannes Kepler in 1614 calculated that a similar Jupiter-Saturn alignment in 7 BC, in the constellation Pisces, would have been read by Babylonian astrologers as a sign of a major king being born to the Jewish people. The 2020 alignment was also in Pisces (technically the Capricorn-Aquarius border, very near Pisces) which gave the event additional historical resonance.
When the Next Christmas Stars Happen
Jupiter and Saturn meet again roughly every 20 years, but most pairings are several degrees apart. Truly close conjunctions like 2020’s happen far less often.
- November 2, 2040: Jupiter and Saturn within 1.1 degrees.
- April 7, 2060: Jupiter and Saturn within 1.1 degrees.
- March 15, 2080: within 6 arcminutes (about 0.1 degree). The next equivalent of 2020.
Frequently Asked Questions
Was 2020’s Christmas Star the closest in history?
Not since the year 1226, no. The 2020 conjunction was the closest visible from Earth in 397 years.
How long was the conjunction visible?
About 2 weeks of close pairing leading up to and following the December 21 peak. On the peak night and the two nights either side, the planets appeared as a single bright point to the naked eye.
Where should I look for the next great conjunction?
Shortly after sunset, low in the western sky, on the days listed above. No telescope needed, though a small telescope shows both planets and Jupiter’s four major moons during the pairing.
Was the original Star of Bethlehem really a Jupiter-Saturn conjunction?
Plausibly. Kepler’s 1614 calculation showed a triple Jupiter-Saturn conjunction in 7 BC was unusually close and in a constellation with cultural significance to Babylonian astrologers. It remains the leading scientific candidate.
Joe Rao
Joe Rao is an esteemed astronomer who writes for Space.com, Sky & Telescope, and Natural History Magazine. Mr. Rao is a regular contributor to the Farmers' Almanacand serves as an associate lecturer for the Hayden Planetarium in New York City.
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would you mind rechecking your calculations the month of may is off a few weeks it should be June , allow me to explain, The Star of Bethlehem here almost lines up perfectly with Christ’s birthday , his birthday is clearly written in the first 3 chapters of Luke if you know what your reading , if not you read right past it because it is hidden in plain sight! the first 4 verses in luke tell us it is the most accurate account of things that follow , the 5th verse gives us an exact calendar date, day , week, month and year, its not in May its the end of the 3rd week in June when Elizabeth (Marys cousin) conceives John the baptist , exactly 6 months Mary conceives Jesus “December 25th” and exactly 9 months later in September Mary gives birth to Jesus…. so it was the conjunction between Jupiter and Saturn that made up the star of Bethlehem
We are so blessed to get to see the “almost” christmas star. What a wonderful time to be alive!
Wonderful! We’re glad you got to see it, too!
I found this to send one message. Is science and happening, spiritual, tragic connected to a planetary clock called universal creation and its electro magnetic fields Is some one pushing the buttons.
Are you kidding me? How do you know when Jesus was born and or when he is returning. You need to just humble yourself and be Thankful for both events!
Yes, we do not know when Jesus will return…that’s scriptural. But we do know Jesus was born the end of September by correlating the documented conception of His cousin John.
The Star of Bethlehem could have been in September, as the birth of Christ was during the fall of the year, not in December.
What difference does that really make????
Actually the birth of Christ was in the late spring or early summer, when the taxes were being collected. The catholic church took over the pagan ritualism of the winter solstice to keep control over the people
Are you serious?! Jesus is a Jew!
Was. He was converted by John the Baptist, developed and taught “CHRISTianity to His followers. By all means, He is the Son of God.
Jesus was the son of God, crucified and rose from the dead and later ascended to Heaven to be with God . He will return again to gather all those who believe this. Jesus was never anything else so he was not in need of a conversion. He was simply baptized by John to be the example. We need to be careful saying that God was converted.
???????????? “The Sheperds Were directing the sheep to the bottom toward the shelter .
Could they hit eachother if they got closer? Could Saturn’s rings be damaged if they got to close?
?
Hi Erica, On Dec. 21st, Saturn and Jupiter will be about 455 million miles apart. To our eye, they look close but in reality, they are very far apart. They will never be close enough to disrupt Saturn’s rings- so, don’t worry. All’s well.
The Jupiter and Saturn are not in the same orbit around the sun. It is our perspective from Earth that shows them so close. They aren’t actually close at all, just lined up in their orbit to appear as one.
Please, please tell me you are joking…
They said that the two planets would be 420 million miles apart
they are still in orbits very far apart just lined up in a plane that we can see the on close together in 2D…but gravity waves are now going to tug at our magma and POP goes the supervolcano ;p