Jimmy Westlake: What is the Star of Bethlehem?
December 23, 2013
Steamboat Springs — About 2,000 years ago, St. Matthew recorded that something extraordinary appeared in the sky over Bethlehem of Judea that accompanied the birth of Jesus. For centuries, astronomers have wondered about the nature of this Star of Bethlehem. Was it a one-time supernatural event, never seen before and never seen since?
While that is a possibility, it seems unlikely that St. Matthew would have been the only person to record the appearance of an amazing event like that. Another possibility is that the Star of Bethlehem was a rare but natural celestial event that might have gone unnoticed by the masses but would have caught the attention of sky watchers, such as the Magi mentioned in St. Matthew's gospel.
Assuming this to be the case, what type of object could it have been? A bright comet would have been noticed and recorded by sky watchers world wide, so that seems unlikely. The spectacular death of a nearby star in a supernova explosion would have made a brilliant and temporary star in the heavens, but supernovas leave tell-tale signs like expanding clouds of gas that modern astronomers would have found, had there been one.
The best explanation for the Star of Bethlehem is that an unusual grouping of the bright planets in the sky might have been interpreted by sky watchers of the day as a sign heralding the birth of a King.
Running the solar system clock backwards, astronomers have identified two very unusual groupings of the planets, either of which might have been the Star of Bethlehem, one occurred in 7 B.C. and the other in 2 B.C. Both of these planetary groupings involved the planet Jupiter, the king of the planets.
Over the course of several months in 7 B.C., the planets Jupiter and Saturn had a rare triple conjunction while in the constellation of Pisces, the Fish. On the morning of June 17 in the year 2 B.C., the two brightest planets, Jupiter and Venus, appeared to pass so close to each other that they would have briefly blended into a single bright star.
Could one of these unusual planetary conjunctions have been the heavenly sign that launched the Magi on their journey westward to Jerusalem where they found the infant Jesus? Unless other ancient records are found that give us more and better clues, this is as good a guess as any that astronomers can make.
This Christmas season, both Venus and Jupiter are visible in our evening sky. Dazzling Venus glows brightly in the southwestern sky right after sunset, just as brilliant Jupiter is rising in the east.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out "Jimmy's 2014 Cosmic Calendar" of sky events on his website at http://www.jwestlake.com. It features twelve of his best astrophotographs and a day-by day listing of cool celestial events that you and your family can enjoy watching in 2014. Proceeds from the sale of Cosmic Calendars help to support the CMC SKY Club.