Astronomical explanations for the biblical Star of Bethlehem

In Christian tradition, the Star of Bethlehem guided the magi to the town of Bethlehem, where they meet the baby Jesus and present him with gifts of gold, frankincense and myrrh – but what was this light that guided them, and is there astronomical truth to its Biblical appearance?
According to David A. Weintraub, an astronomy professor at Vanderbilt University, there are several mysteries surrounding the story as told in the Gospel of Matthew. First, why were the magi, who were travelers from a distant land, able to see the bright star when local officials in King Herod’s court were apparently unaware of its appearance in the sky?
In addition, in order to reach Bethlehem, the wise men had to travel directly south from Jerusalem, but somehow the star was “in the east” and “went before them” until it led them to the place where Jesus lived, Weintraub said. But how could a star in the east guide the magi to the south instead of to the east, like how the north star guides people to the north?
Finally, he asks, how could the star have moved “before them,” acting like the tail lights of a snowplow that a person might follow during blizzard-like conditions, and then stop and remain stationary over the home of the infant Jesus. So if the Star of Bethlehem was an actual astronomical phenomenon, exactly what could it be?
“The astronomer in me knows that no star can do these things, nor can a comet, or Jupiter, or a supernova, or a conjunction of planets or any other actual bright object in the nighttime sky,” Weintraub wrote in an article for The Conversation. “One can claim that Matthew’s words describe a miracle… but Matthew chose his words carefully and wrote ‘star in the east’ twice, which suggests that these words hold a specific importance for his readers.”
So is there an explanation that is consistent with Matthew’s choice of words, while not violating the laws of physics and is relevant to the field of astronomy? The answer is yes, according to the Vanderbilt professor.
For starters, astronomer Michael Molnar explained that the term “in the east” is a literal translation of the Greek phrase en te anatole, a technical term used by Greek mathematical astrologists some 2,000 years ago. It was used specifically to describe a planet that would rise above the eastern horizon just before the Sun appeared, then would disappear in its glare in the morning sky. The planet could only be seen for one brief moment.
“We need a little bit of astronomy background here,” Weintraub wrote. “In a human lifetime, virtually all the stars remain fixed in their places; the stars rise and set every night, but they do not move relative to each other. The stars in the Big Dipper appear year after year always in the same place. But the planets, the Sun, and the Moon wander through the fixed stars; in fact, the word planet comes from the Greek word for wandering star.”
While the sun, moon and planets all travel along essentially the same path through the other stars, each of them move at different speeds, causing them to occasionally lap each other. If the sun catches up with a planet, that planet cannot be seen until the planet reappears. Once the planet reappears for the first time in months, it is known to astrologers as a heliacal rising.
“A heliacal rising, that special first reappearance of a planet, is what en te anatole referred to in ancient Greek astrology. In particular, the reappearance of a planet like Jupiter was thought by Greek astrologers to be symbolically significant for anyone born on that day,” he explained. “Thus, the ‘star in the east’ refers to an astronomical event with supposed astrological significance in the context of ancient Greek astrology.”
For the issue of the star coming to a stop, Weintraub once again turns to the original Greek word translated as “stood over,” epano, which also has a special meaning in ancient astrology. He said that it refers to a particular moment in which a planet stops moving and appears to change direction from westward motion to eastward motion – a phenomenon which occurs when the Earth, which orbits the sun more quickly than other worlds, catches up to or passes one of them.
“Together, a rare combination of astrological events (the right planet rising before the Sun; the Sun being in the right constellation of the zodiac; plus a number of other combinations of planetary positions considered important by astrologers) would have suggested to ancient Greek astrologers a regal horoscope and a royal birth,” he explained.
Molnar told Weintraub that he believes that the magi were actually wise astrologers who were adept at mathematics and were aware of the Old Testament prophecy foretelling the birth of a Messiah in the bloodline of King David. It was likely that they would have been watching the skies for years looking for the alignments that would have indicated the birth of this individual, and set out on a journey once the heavens indicated that the time was right.
“If Matthew’s wise men actually undertook a journey to search for a newborn king, the bright star didn’t guide them; it only told them when to set out,” the professor said. “And they wouldn’t have found an infant swaddled in a manger. After all, the baby was already 8 months old by the time they decoded the astrological message they believed predicted the birth of a future king.”
“The portent began on April 17 of 6 B.C. (with the heliacal rising of Jupiter that morning, followed, at noon, by its lunar occultation in the constellation Aries) and lasted until December 19 of 6 B.C. (when Jupiter stopped moving to the west, stood still briefly, and began moving to the east, as compared with the fixed background stars),” he added. “By the earliest time the men could have arrived in Bethlehem, the baby Jesus would likely have been at least a toddler.”
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