"Now after Jesus was born in Bethlehem of Judea in the days of Herod the king, behold, wise men from the East came to Jerusalem, saying, Where is He who has been born King of the Jews? For we have seen His star in the East and have come to worship Him." (Matthew 2:1-2)
This is the only biblical reference to the Star of Bethlehem - the star that is supposed to have foretold Christ's birth. But what was this "star in the East?"
This has puzzled both astronomers and theologians for thousands of years. Astronomers because they have wanted to understand the science. Theologians because they were interested in establishing a divine birth.
With the aid of modern planetariums and computer programs that can map the stars, the science has been worked out by astronomers. They are now able to calculate the position of the stars and planets in the years just before the time ascribed to the birth of Christ and, from these calculations, they have been able to postulate scenarios for the star. Indeed, they have produced many scenarios of astronomical phenomena that could be the "star of Bethlehem."
The first question in this mystery that must be answered is when was Christ born?
This sounds like a silly question. After all, the most obvious answer would be Dec. 25, 1 (0?) A.D. (or B.C.?) or, at least, something like that.
However, Luke 2:8 says "Now there were in the same country shepherds living out in the fields, keeping watch over their flock by night."
Keeping a night time watch over sheep was something that shepherds only did (and still only do) during the spring, when the ewes are giving birth. This would mean that Christ is more likely to have been born in March than December. Furthermore, the year of Christ's birth and our modern calendar system were not established when he was born, but five centuries later. In 530 A.D., Dionysius Exiguus devised a calendar for which he ascribed the year of "Our Lord's Birth" as the starting point. He worked backwards from historical records to determine when that occurred.
And he got it wrong.
The census that called Mary and Joseph to Bethlehem during the reign of Herod would suggest that Christ was actually born in 4 or 5 BCE (before Herod's death in the spring of 4 BCE). The date of the census has been recorded elsewhere and through better sources of the historical record. This is the date now accepted by most Biblical scholars.
So, what was the Star of Bethlehem? The magi were likely Zoroastrian priests who practised astrology. They were familiar with the night sky because they believed that the movement of the sun and the wandering stars (planets) foretold the future.
They don't, but that is a whole other column.
In observing the sky, they would have noticed a most unusual occurrence in the fall of 8 B.C. and spring of 7 B.C.
In the constellation Pisces (the astrological sign that occurs in late February and early March), a conjunction occurred between the planets Jupiter and Saturn.
This gave the appearance to the magi that the planets were "getting together" for an event of some significance. As the weeks progressed, this congregation of the planets disappeared from the evening sky behind the sun.
When Jupiter and Saturn returned to the morning sky (in the east), instead of going their separate ways, they got together a second time. And, because of the fact that the Earth travels very much faster in its orbit than either Jupiter or Saturn, a third conjunction was observed a few months later. This triple conjunction of Saturn and Jupiter is a most unusual event as it occurs only once every 973 years.
The scenario postulates that magi observed this event of great celestial significance occurring in Pisces, the constellation ascribed to Judea, and concluded that a momentous event was to occur in late February or early March in Judea. So, they presumably started their search, eventually reaching Bethlehem about two years later, around the time Christ was born.
Is this triple conjunction of Jupiter and Saturn the Star of Bethlehem? Nobody knows for sure, but it is one of the possible explanations for what might have happened over 2,000 years ago.