Astronomy: For ages, the Star of Bethlehem has been an object of speculation. Was it a comet? Or was it a visual convergence of planets? Maybe a nova? The questions remain unresolved today. But the lack of a definitive answer only adds to the wonder of the season.
Last Tuesday's flaming green meteor was a reminder, even in Seattle's light-polluted skies, of how striking astronomical events can be.
And the star that sits atop many Christmas trees - a tradition that began in Sweden - is a symbol of one of the most charming chapters in the story of Jesus' birth: that three "wise men," or astrologers from the East, followed a star to Bethlehem to pay homage to the Christ child.
The story is also one of the most controversial. If such a star existed, shouldn't there be independent astronomical records of its widespread observation? And if it did not exist, doesn't such an error throw doubt on the entire Christmas story?
Believers, of course, can simply claim the star was a supernatural miracle outside ordinary explanation. Doubters can dismiss the entire nativity story as a fable made up decades after Jesus' death.
But astronomers have tried to apply science to the question and have come up with not just one candidate for the Star of Bethlehem, but several. The problem is deciding which one is most likely.
The Gospels were written many decades after Jesus' death. Only two of the four primary biographical Gospels of Jesus discuss his birth, and only one, Matthew's, mentions the star and visit of the Magi. Contrary to modern depictions, Matthew seems to suggest the wise men or astrologers arrived when Jesus was a very young child, not a newborn.
We three kings of orient are
Later tradition, not the Gospels, elevated the emissaries to "kings," gave their number as three, had them bringing presents and assigned names: Caspar, Melchior, and Balthasar.
Matthew and Luke agree that Jesus was born in Bethlehem in the last years of the reign of Herod the Great, that a heavenly messenger announced the birth and that his actual hometown was Nazareth.
But Luke makes no mention of wise men, or a star, or of a fearful Herod slaughtering infants in Bethlehem, or the Holy Family fleeing to Egypt. Matthew makes no mention of a trip to Joseph's hometown of Bethlehem for a Roman census, no mention of a crowded inn and no mention of a manger or angels appearing before shepherds.
Such discrepancies are not surprising. The Gospel authors wrote in an age of oral history, biographical myth and without the standards of science, history or journalism that people take for granted today.
But if ancient imprecision can be forgiven, it still makes it difficult for astronomers to tie Jesus' birth to a specific astronomical event. Star hunters can't even be sure when Jesus was born, except to agree that it almost certainly was not Dec. 25 in the year 1 A.D.
The December date used to celebrate Christmas falls near the winter solstice, which marks the shortest day of the year and the return of the spring sun. It was a time of celebration for both Romans and Parthians. The early Church is believed to have appropriated the holiday to commemorate the uncertain date of Jesus' birth.
While shepherds watched
Luke's statement that "there were shepherds living in the fields, keeping watch over their flock by night," suggests to biblical historians that Jesus' birth occurred in the spring. That was when lambing season would require the shepherds to temporarily camp out with their flocks.
Historians also tend to assume that Jesus must have been born before Herod the Great died, in 4 B.C. (though even that date is in some dispute) and that he died sometime during the Roman administration of Pontius Pilate, who was procurator of Judea from 26 to 36 A.D.
If Jesus was "about" 30 years old when he began his ministry - as the Bible suggests - and was crucified two to three years later, as most scholars believe, the earliest he could have been born was about 7 B.C.
Another clue is that Luke said the Roman census that brought the Holy Family to Bethlehem occurred "when Quirinius was governor of Syria." This was 6 to 4 B.C. Unfortunately there is no record of a census at that time.
The consensus is that Jesus was born between 6 and 4 B.C. In fact, it is likely we are closer to the 2,000th anniversary of Jesus' birth right now than we will be in 2001.
Star of royal beauty bright
So what was going on in the sky at that time? There are several Star of Bethlehem candidates, nicely summarized in a 1995 paper by University of Washington astronomy graduate student Nick Strobel:
-- Halley's Comet, which swings close to the Earth every 76 years, made an appearance in about 10 B.C. It would have been a dramatic, once-in-a-lifetime phenomenon likely to catch an astrologer's eye - but probably occurred too early to coincide with Jesus' birth.
-- In March of 5 B.C., Chinese astronomers recorded an exploding star or nova in the constellation Capricorn that shined for 70 days. This is potentially time enough for the wise men to have traveled from their home (some scholars suggest that Persia - modern-day Iran - was a likely origin) to Bethlehem.
A nova can increase a star's brightness from 10,000 to a million times, and the timing is intriguingly close to lambing season. The nova rose in the eastern sky, fitting Matthew's quote of the Magi: "We have seen his star in the East." But its position in the sky certainly did not point the way from Persia to Israel, nor from Jerusalem to Bethlehem, as Matthew suggested: "There, ahead of them, went the star that they had seen at its rising, until it stopped over the place where the child was."
-- Jupiter and Saturn came close together three times in 7 B.C. in the constellation Pisces, a phenomenon that occurs only once every 900 years. To ancient astrologers, Pisces was associated with the Hebrew nation.
This timing, too, is intriguing: The first conjunction occurred in late May, when the Magi may have set out; the second in September, when they may have paid court to King Herod in Jerusalem; and the third in early December, when Herod may have sent them on to Bethlehem.
The event would not have been noticed much by laymen; the two planets only came close to each other, separated by a distance about twice the width of the moon. They never looked like one star. But the conjunction would have been noticed by trained astronomers or astrologers and could have been interpreted as marking an event of great significance. The conjunction also would seem to set each night in the direction of Judea from Persia.
-- Another possibility was the rare conjunction of three planets in February of the following year, or 6 B.C., when Mars, Jupiter and Saturn came within 8 degrees of each other low in the western sky. Again, laymen might not have been impressed, but astrologers would have recognized the event, which occurs only once every 800 years.
-- In early September of 5 B.C., Jupiter underwent what appears to observers on Earth to be retrograde motion - it seemed to make a loop against the surrounding stars. This, too, was likely to have been noticed and deemed significant.
-- Comets were reported in both 5 and 4 B.C. This seems a bit late, if Herod thought he had to slaughter children up to 2 years old before his own death in 4 B.C. But comets, because of their tails, do seem to point to something.
-- On June 17, 2 B.C., there was a brief conjunction of Jupiter and Venus in which the two planets appeared to come together in the west. Because Venus is much brighter than Saturn from Earth, this might have been more visible to the naked eye. However, the date does not coincide with Herod's reign.
In the company of angels
There are more mystical interpretations. In a 1993 article in Bible Review, theologian Dale Allison argues that Matthew's description of a moving, guiding star is so un-starlike that it makes more sense to assume it was a guiding angel than a true astronomical object. He contends the ancients had no idea what stars actually were, and would have called a miraculous guiding light a "star."
A more skeptical interpretation is that Matthew was striving after the fact to give significance to Jesus' birth and simply made up the star story, borrowing from the common claim by the ancients that the birth of great people was accompanied by astronomical portents.
Then again, the visit of the Magi may not have been all that unlikely. Persia's Zoroastrian religion had predicted that a king would be born to the Jewish people in Bethlehem and that the event would be marked by a sign in the sky.
It is unlikely we will ever know for certain, and certainly the truth of the Christmas star is of marginal importance to religious faith or taking meaning from Christmas.
But did something happen in the sky 2,000 years ago? You bet: several things. Whichever one intrigued the Magi, we do know that it's an exciting universe up there.