The Gospel of Matthew records a celestial event that guided the three Magi (a.k.a. "wise men") to Bethlehem where the baby Jesus awaited. This story of the Christmas star, also known as the star of Bethlehem, not found anywhere else in the Bible, has been the subject of theological study and debate. The validity of the event is perhaps left to the theologians, so for our purposes lets suppose that the Christmas star appeared in the sky that fateful night. What was this celestial event?
Theories of the Christmas Star (Star of Bethlehem)
There are several celestial possibilities that would explain the text appearing in the Gospel of Matthew.
- A Planetary Conjunction: A conjunction is an alignment of heavenly bodies. In this case, a planetary conjunction of Jupiter and Saturn occurred in 7 B.C., a year commonly put forth as the possible birth year of Christ. While possible, the separation of the planets would have been about a degree, which is not close enough to necessary struck the Magi as being important.
- Conjunction of Uranus and Saturn: Put forth as a possible event of significance to astrologists (which the Magi would have been), a passing of Uranus near Saturn would not have been visually interesting as Uranus is incredibly dim. In fact, it is nearly imperceptible with the naked eye.
- A Comet: Halley's comet is another common explanation. However it would have appeared in 12 B.C. which is perhaps too early. Though another comet passing by Earth could very well have been the astronomical event. They have a tendency to "hang" in the sky for extended periods of time as they pass near Earth over days or weeks. They also had astrological significance, though not always in a positive way.
- A Supernova Explosion: Like comets, supernovae tend to "hang" in the sky for extended periods of time. They are visually impressive, some lighting up the night sky as if it were day. A supernova is recorded in Chinese history around 5 B.C., though some have argued that it was instead a comet, offering a possible event coinciding with the birth.
- Occultation of Jupiter: Jupiter is considered the "King" of the planets and held special significance in ancient religions, as well as astrological significance. In 6 B.C., there were two occultations of Jupiter buy the Moon. This may have been taken as a sign that a "kingship" was being conferred.
What is the Significance of Such Astronomical Events?
The Magi were likely keen astronomers and astrologers, which means that whatever event transpired would have needed to have special significance; something that was extraordinary.
It is not likely that a planetary conjunction or alignment would have caught the eye of the Magi.
The occultation of Jupiter makes a lot of sense, and even presses all the right buttons for holding astrological significance as well as religious connotations. The problem being that it wouldn't have necessarily indicated the direction in which to travel. Plus the event would have been over rather quickly.
In contrast a passing comet or the presence of a supernova would have persisted for much longer in the night sky, and could have indicated a preferential direction of travel. Comets would have been observed previously though, so the significance to this comet is not understood. A supernova however would have been more rare.
While there may never be definitive proof of the events recorded in the opening chapters of Matthew, there are some possible astronomical explanations. Which one is correct? The debate is still ongoing.