https://www.space.com/astronomy/comets/the-comet-of-bethlehem-why-we-may-need-to-rethink-a-popular-christmas-story
https://britastro.org/journal_contents_ite/the-star-that-stopped-the-star-of-bethlehem-the-comet-of-5-bce
Could the Star of Bethlehem have actually been a comet?
December 16, 2025
Could the Star of Bethlehem, which guided the 'three wise men' to the infant Jesus in the Christian Bible, have been a comet that came as close to the Earth as the moon?
That's the remarkable hypothesis from Mark Matney, a planetary scientist in NASA's Orbital Debris Program Office by day and a self-declared Christmas junkie.
"I love Christmas," Matney told Space.com. "I love Christmas music, I love Christmas decorations โ I love the whole thing!"
It was this love of Christmas, expressed in a festive show at the planetarium that Matney worked at when he was in college, that inspired his interest in the Star of Bethlehem.
A passage in the Bible's Book of Matthew describes how the star went before the wise men โ known as 'magi', who were probably astrologers looking for signs in the sky โ and stood over Bethlehem.
The planetarium show suggested that no known astronomical event behaves in this bizarre way, but rather than accept that, Matney saw it as a challenge. "I remember sitting there and thinking, I can think of one thing that can behave that way," he recalled.
For Matney, there are three ways to look at the story of the Star of Bethlehem. One, which is how those of a religious leaning might see it, is as a miraculous, divine event, the archangel Gabriel shining the way towards the baby Jesus.
Another, more cynical, view is to believe the whole story to be a myth, at best perhaps a misrepresentation or embellishment. If the Star of Bethlehem was either of these two things, then there's no point in looking for a scientific explanation.
On the other hand, the third way of looking at it is as a real astronomical event. Over the years, astronomers have suggested everything from a conjunction of Jupiter and Saturn to a supernova and, yes, a comet.
The problem with all previous astronomical explanations, says Matney, is that "objects in the sky, whether it be the sun, moon, planets, ordinary stars or normal comets, rise in the east and set in the west, they don't go before you and hover over a location."
However, Matney realized that if an object came close enough, at just the right time, moving in just the right direction at just the right speed through the sky, then it could appear to do these things.
"I came up with the idea of temporary geosynchronous motion," said Matney. "It has to be just right, but in principle it can happen."
The Chinese comet of 5 BCE
Matney filed his idea away in the back of his brain, until later when he learned that Chinese astrologers (astronomers and astrologers back then were synonymous) had seen a bright comet in 5 BCE, which is believed to be the year that Jesus was born.
The recorded observations of the comet are not sufficient to chart its exact orbit, but instead its measured positions in the sky could belong to a range of possible orbits.
By running numerical simulations describing all these possible orbits, Matney found a subset of orbits that would have brought the comet close to Earth, and one possible orbit where it would have been close as Earth's moon.
Matney isn't saying that the comet definitely came that close โ it's just one of a number of possible orbits the comet could have had.
Had it done so, however, it could be a tantalizing explanation for the Star of Bethlehem, explaining a great many things.
The Christmas festivities tell us that Jesus was born on Dec. 25, but theologians and historians aren't actually sure of his birth date.
However, the Chinese comet was discovered in mid-March, 5 BCE and, in the possible orbit flagged as being of interest to the Star of Bethlehem story, it would have reached its closest point to Earth on June 8 that year.
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