The star of Bethlehem, which Christian lore maintains led the wise men to the birthplace of Jesus, is one of the most enduring and well-known Christmas legends. Almost as enduring among sky-watchers is the question of whether an ordinary (that is, non-miraculous) astronomical event could have fit the biblical description of the star.

The star appears in the Book of Matthew, which chronicles its appearance as spurring the wise men to seek out King Herod in Jerusalem and then guiding them to Bethlehem. So some astronomers have taken the reign of Herod as a time parameter and scanned the ancient skies for likely candidates using software that reconstructs the locations of celestial objects thousands of years in the past or projects their locations thousands of years in the future.

One popular explanation is a conjunction of the two brightest planets, Jupiter and Venus, which appears to have occurred in June of the year 2 B.C. Those two planets, drawing close to one another, would have appeared as a single point of intense light in the night sky. But many estimates for the death of Herod peg the king as having perished by that time.

Another candidate for the legendary star is a nova, or brightly flaring star, that Chinese astronomers recorded in 5 B.C., a theory discussed in depth by Mark Kidger in his 1999 book The Star of Bethlehem: An Astronomer's View.

Nick Strobel, an astronomer who teaches at Bakersfield College, a community college in California, maintains an extensive Web page examining the various theories about the star of Bethlehem. Strobel acknowledges that there may be no literal, historical basis for the star's appearance as described in the Bible, but he believes that an earlier planetary conjunction, in 6 or 7 B.C., is a better fit, as is Jupiter in retrograde motion, during which it would have appeared frozen in the sky for a number of days.

Of course, any attempt to scientifically validate or invalidate pieces of scripture is sure to rankle some (read: many). And even if the star of Bethlehem really did exist, the tools of astronomy may never be sufficient to point out what it was. As Phil Plait, who writes the blog Bad Astronomy, put it, "The astronomical evidence is interesting, but interpreting it should be done with a pillar grain of salt."

Image credit: NASA/ESA