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The Star of Bethlehem

Have you ever wondered if the Star of Bethlehem was a real star in the sky? Michael Molner, a retired astronomer from Rutgers University in his 1999 book (“The Star of Bethlehem: The Legacy of the Magi,” Alibris Books) reviews the positions of the planets, traces back in time, and combines that with the astrology that would have been practiced by the Parthians (the “wise” men from the East). First some facts: (1) the wise men saw “his star in the east”… (2) upon hearing this, Herod “was troubled”, and (3) again from Matthew: “when they had heard the king, they departed; and, lo, the star, which they saw in the east, went before them, till it came and stood over where the young child was.”

How can we make sense of this? First, “his star” refers to the planet always associated with kings, namely Jupiter. “In the east” refers to a common term for a star (planet in this case) rising in the east just before dawn, a so-called “heliacal rising”, which clearly defines a particular day since the day before that the star was visible in the dark sky and the day after that the star was beginning to be lost in twilight. Second, Herod was troubled because no one in Judea thought about astrological events and their meanings, so they did not know there was a sign of a new king. Also, the Parthians used the Greek system in which the planetary positions were known from tables and not by looking up, so the Parthians could identify important events that the Jews might not even have seen.

Third, the star (Jupiter) going “before them” was a common term that referred to the retrograde motion of a planet, when, because the Earth is moving faster in an inner orbit, the planet appears to move backward in the sky. With regular motion, the planet goes a little slower than the background stars from night to night, and with retrograde motion, the planet goes a little faster than the background stars: it “goes before”. Also, “till it came and stood over where the young child was” refers to the end of the retrograde motion when the planet stops moving faster than the background stars and turns around to move in its regular motion again. Moreover, this stopping, along with the heliacal rising, happened in the zodiacal sign of Aries, which to the Parthians represented the geographic region of Judea. So, Jupiter stopped its retrograde motion in Aries, representing Judea “where the young child was.”

If you look outside now on a clear night, you will see the bright planet Jupiter straight overhead in the early evening. It is currently in retrograde motion and will “stop” in the constellation Taurus on December 30th. What is interesting about the timing of the events mentioned above is that the Heliacal rising of Jupiter occurred on April 17th, 6 BC, the same day when the moon went directly in front of Jupiter at around noon-time. All of this happened in Aries, presenting a very strong message to the wise men and possibly causing them to leave home for a several-month trek to Judea. It then “stood over where the young child was” on December 19th, 6 BC. It is nice to think that the image of the star over a manger in our winter celebration of Christmas is accurate.

Bruce Elmegreen


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