At this time of year, people often ask for my astronomical/religious opinion: "What was the Star of Bethlehem?" What was this heavenly sign that a savior, that a Messiah, that Jesus was born? Can modern science prove what this object really was?
Mercury is the planet governing communication, transportation and truth. When it is in "retrograde," its movement appears to be streaming backward in the skies, and that backward intention affects all forms of communication.
If you think of the Earth within the context of the universe(s), it is difficult to cling to any certainty you may have about the significance or uniqueness of our planet, and thus the degree of specialness we like to attribute to its inhabitants.