Mercury stations retrograde on January 30, 2100 at 25° Aquarius, and direct on February 20 at 10° Aquarius — 21 days. From the Earth, Mercury seems to back up against the stars as we overtake it, as a car passed on the highway seems to slide backward. Astrology holds it a time for crossed wires and delays. Computed from JPL's approximate orbits; the stations agree with an almanac's to within minutes.