The light at night may have been a localized event, but a new star would be seen all over the world. In the Old World the appearance of the star was both sign and guide for the wise men. It is a sign only, not a guide, in the New World. With the Mesoamerican penchant for astral observation (see commentary accompanying Helaman 12:15), however, it would certainly have been noticed and remarked upon as significant.