Science Tests Theories on the Star of Bethlehem

Mark Kidger of the European Space Agency confesses to a certain obsession at this time of year -- one that has nothing to do with the big bang or dark energy. "It's probably the oldest mystery in astronomy," the British scientist said.

Kidger is speaking of the "Star of Bethlehem," the heavenly sign in the Gospel of St. Matthew that guided the wise men in their search for the baby Jesus.

Although it is no longer a staple of planetarium shows, the star and its story remain as fascinating for astronomers and historians on this Christmas Day as they have for almost two millenniums.

Modern technology and scholarship have opened many new windows on the event -- and a bibliography on the topic runs into the hundreds of titles. Kidger has been hooked on the subject since he was 17. "It's a fabulous story," he said, and "at the moment, it's almost impossible to prove one or the other of the rival theories is right. You can have your opinion, but nobody can say they're definitively right on it."

Was it a comet? A supernova? A spectacular convergence of bright planets? Can we run our celestial computers backward and rediscover it? Or was it a myth or a miracle, inaccessible to science?

"It may be asking too much of astronomy and history to provide an actual event," said Owen Gingerich, a retired professor of astronomy and the history of science at the Harvard-Smithsonian Center for Astrophysics. "This could simply be an interpretive myth to make a point. ... I think we just do not know." That hasn't stopped generations of researchers from seeking an answer.

Here's where everyone begins:

Wise men from East

The story of the Star of Bethlehem resides in just one source, the Gospel of St. Matthew. It says "wise men" traveled to Jerusalem from "the East" to inquire about "he that is born king of the Jews." They told King Herod, "We have seen his star in the east and we have come to worship him.

"Historians believe the "wise men" were learned astrologers, perhaps Jews from Babylon in what is now Iraq, or Zoroastrians from Persia -- now Iran. The Gospel says they arrived in Judea during the reign of King Herod, who died in 4 B.C. The Gospel suggests that Herod hadn't seen the star himself. But his priests, citing prophesy, directed the wise men toward Bethlehem. And the star, "which they saw in the east went before them, till it came and stood over where the young child was." In A.D. 248, the Egyptian scholar Origen suggested it was a comet or a new star, not a planet. The Greek words Matthew used suggest that the star appeared suddenly in the east, at the first light of dawn.

"It could be a comet that had come around the sun and become visible, or a nova [an exploding star] which suddenly flared up," Kidger said.

The German astronomer and astrologer Johannes Kepler argued in favor of a supernova after he witnessed one in 1604. That idea prevailed for centuries. But "modern astronomy can show quite clearly that it wasn't a supernova," Kidger said. Such explosions leave tell-tale remnants of glowing gas that can be seen and dated. "And there is nothing there that is 2,000 years old."A planetary conjunction? Modern computers enable astronomers to determine precisely where all the planets visible to the naked eye were during that period in the last decade B.C.

Rare conjunction

A big break came in 1968, when Roger W. Sinnot noted an extremely close conjunction of the bright planets Venus and Jupiter on June 17, in the year 2 B.C. Writing in Sky & Telescope magazine, Sinnot said the conjunction was so tight that "the fusion of the two planets would have been a rare and awe-inspiring event."