Planetologist from NASA Mark Matney proposed the theory that the comet referred to in the Bible as the Star of Bethlehem could have been on a collision course with Earth. In his view, this would explain why observers described the object as remaining stationary in the sky.
The scientist presented his theory in early December in the Journal of the British Astronomical Association. Matney re-examined the previously known account of a comet appearing in a Chinese chronicle from 5 BCE. The object was reportedly visible in the spring of that year for 70 days. Historians also generally date the birth of Jesus between 6 and 5 BCE, since according to them, King Herod died no earlier than the end of 5 BCE.
The NASA expert applied an innovative numerical technique to investigate what the trajectory of a comet would look like if it approached Earth closely enough that, when observed, it would appear stationary in the sky. This phenomenon is known as temporary geostationary motion.
According to Matney, this explains the description in the Gospel of Matthew that the Star “went ahead of” the Magi from the East on their journey to Bethlehem, until it stopped over the place where Jesus was born.
The researcher stated that the comet would have had to pass extremely close to Earth, at a distance of 380,000 to 400,000 km, roughly the distance to the Moon. In his article, Matney cites the example of Comet Siding Spring, which in 2014 passed 141,000 km from Mars, about one-third the Moon–Earth distance.
Although such close encounters are rare, they are possible, he writes.
The scientist admits that he had very limited sources. He himself states that his goal was not the direct identification of the Star of Bethlehem but the proposal of a plausible object that could match the preserved descriptions.
As reported by the British newspaper Times, so far there have been “at least 400 scientific attempts to explain the origin of the Star of Bethlehem,” many of which are contradictory. Among them, Johannes Kepler, the 17th-century German astronomer and mathematician, favored a conjunction of Jupiter and Saturn in 7 BCE. Others suggest that a star might have exploded at that time. For many, however, the phenomenon described in the Bible is understood as a miracle or a symbol.