From an astronomical perspective, to answer this question, one would need to know the exact date of Jesus' birth. His birth likely didn't occur exactly 2,025 years ago. The current system of counting years was not introduced until the 6th century CE, and its creator miscalculated by about 4-6 years. The reign of Herod the Great, who died around 4 BCE, remains one of the few solid points of support. We also don't know exactly who the Three Wise Men were; their names (Caspar, Melchior and Balthazar) come not from the Bible but from later Christian tradition. Even the commonly accepted date of Christmas has primarily symbolic meaning.
We are therefore left to speculate on what the Star of Bethlehem might have been. One of the most frequently cited hypotheses involves the so-called Great Conjunction of Jupiter and Saturn. This is a rare phenomenon in which the two planets appear very close to each other in the sky, despite being separated by vast distances. Jupiter and Saturn are easily visible to the naked eye, both due to their size and their ability to reflect sunlight. Their positions in the sky can be calculated today with great accuracy, even with reference to ancient times. In 7 BC, Jupiter and Saturn were in conjunction three times, making this phenomenon a particularly compelling candidate.
In many Christmas nativity scenes, the Star of Bethlehem is depicted with a long tail, reminiscent of a comet. Comets are celestial bodies composed primarily of ice and rock that typically orbit the Sun in highly elongated orbits. As they approach the Sun, some of the ice sublimates, releasing gas and dust, resulting in the characteristic tail. Although comets constantly move against the background stars, this motion is slow enough that they can remain visible in the same region of the sky for at least several days. Interestingly, Chinese astronomers recorded the appearance of a bright comet in 5 BC, which is sometimes cited as one possible astronomical interpretation of the Star of Bethlehem [4]. The exact trajectory of this comet is unknown, and ancient records do not allow for a clear determination of its orbit. If it was a long-period or one-time object, it may be so distant today that it remains completely invisible.
A less popular hypothesis suggests a nova or supernova explosion. A nova is a violent thermonuclear explosion that can occur in certain binary star systems. A supernova, on the other hand, is the spectacular end of the lives of massive stars. Both phenomena, visible to the naked eye, appear very similar in the sky as point-like brightening, which is why they were long classified as the same type of object. However, there are no convincing sources or astronomical evidence confirming that a star of this type exploded at the appropriate time.
It's impossible to definitively determine today what the Wise Men from the East actually saw. From the perspective of modern astronomy, the Star of Bethlehem could have been a planetary alignment, a comet or a sudden stellar flare. People of two thousand years ago didn't understand the physical nature of such phenomena, so any of them could have been interpreted as a clear sign sent from heaven.
Source: mgr Joanna Ślot, Department of Astrophysics, Faculty of Physics and Applied Informatics, University of Lodz, University of Lodz Doctoral School of Exact and Natural Sciences
Edit: Kacper Szczepaniak, Press Office, University of Lodz
