The strange star of Bethlehem

Commentators remark on the unnatural motion of the "star". But presumably that's what caught the attention of the Magi. In general, the motion of the sun, moon, and stars is uniform. Sun, moon, and stars always rise in the east and set in West. There's seasonal variation, but that's uniform, too.

To get the attention of the Magi, we'd expect the "star" to do something highly irregular. And that's explicable if it's a supernatural phenomenon. Some people think the motion of the "star" is unrealistic, but that misses the point. It has to be unrealistic to be sign. If it wasn't something extraordinary, the Magi wouldn't be puzzled by its erratic behavior.