Has a wise man at NASA solved the Star of Bethlehem mystery?

It seems miraculous that a comet would hover, stationary, over a small town. Not if you look at ancient Chinese astronomers’ records, says one scientist.

An artists’ impression of the baby Jesus in the manger with Mary and Joseph in silhouette surrounded by animals and the three wise men with the city of Bethlehem in the distance

Astronomers have debated the truth behind the Star of Bethlehem for centuries.

Now a NASA scientist claims to have presented the first scientifically grounded theory capable of explaining its strange movement in the sky, as described in the Bible.

The answer, he suggests, may involve a comet that very nearly ploughed into the Earth a little over 2000 years ago.

In the Gospel of Matthew, the star that leads the wise men to the infant Jesus first appears “in the east”. It then “goes before” them on their short journey from Jerusalem to Bethlehem, before “standing over” the place where Jesus was born.

Ordinarily, astronomical objects do not hover over small towns. This has driven many to declare the star either a miracle or a metaphor.

Mark Matney, a planetary scientist for NASA, suggests an alternative theory in the Journal of the British Astronomical Association. He revisits an old suspect: an object recorded by Chinese astronomers in 5BC.

In the Gospel of Matthew, the wise men are led by a star from Jerusalem to Bethlehem, before “standing over” the place where Jesus was born.

Ancient Chinese court records, kept for astrological reasons, noted a bright comet visible for more than 70 days beginning in the spring of that year. Historians typically place Jesus’s birth somewhere between 6BC and 5BC, because Herod the Great, who was still alive during the visit of the Magi, died no earlier than late 5BC.

Matney’s contribution is to use a novel technique to look at how this comet might have moved in the sky when viewed from the ground. After modelling a range of possible orbits consistent with the Chinese observations, he identified a set of trajectories that would have brought it close enough to Earth that, for a few hours, its eastward motion would nearly cancel out the effect of Earth’s rotation.

Today, satellite engineers know this phenomenon as “temporary geosynchronous motion”. To observers on the ground, the comet may have appeared to pause in the sky, almost overhead, before resuming its path.

For one reconstruction of the object’s passage, this would have happened on a June morning in 5BC. Seen from Judea, the comet’s position would have been aligned with the road from Jerusalem to Bethlehem while climbing higher in the sky.

Travellers moving south, towards Bethlehem, could plausibly have seen it “going before” them, then lingering overhead as they arrived.

“This is the first astronomical candidate for the Star ever identified that could have had apparent motion corresponding to the description in Matthew, where the Star ‘went before’ the Magi on their journey to Bethlehem until it ‘stood over’ where the child Jesus was,” Matney writes in his study.

The comet would have to have passed extremely closely by astronomical standards: between 236,000 and 249,000 miles (380,000-400,000km) from the Earth, or roughly the distance to the Moon. In his paper, Matney cites the example of the Siding Spring comet, which passed within 87,000 miles (141,000km) of Mars in 2014 - a third of the Moon-Earth distance. “While rare, such close approaches are possible,” he writes.

A comet visible for months would fit with Matthew’s hints that the “star” had been seen for some time.

Moreover, comets were viewed as carrying meaning in the ancient world. In Greco-Roman and Eastern astrology, they were read as heralds of regime change, royal births and divine intervention. For a team of elite astrologers, a conspicuous comet might easily have inspired a field trip.

Of course, none of this solves the mystery definitively. At least 400 scholarly attempts have been made to pin down the truth behind the star and there are rival explanations. Johannes Kepler, the 17th-century German astronomer and mathematician, favoured a conjunction of Jupiter and Saturn in 7BC.

Others have suggested a supernova, an exploding star that would have appeared suddenly. Many remain content with seeing it as a miracle or a myth.

The Times