Though the idea of the planet Mercury being retrograde is a common term discussed by believers in astrology, this concept is based on an observable astronomical phenomenon in which Mercury's orbit appears to get thrown into reverse. In actuality, the planet is still moving forward on its orbit path, but is doing so more slowly relative to the movement of the earth, making the first planet from the sun appear to move backward. In astrological terms, Mercury is seen as a messenger planet, and its backward movement is seen as interfering with all types of communication, from the technological to the interpersonal.
Other astrological impacts of Mercury's perceived backward movement include general disorientation and confusion, including the disruption of plans and a general period of chaos. This apparent backward motion takes place multiple times each year in a predictable fashion, allowing followers of astrology to plan accordingly. While Mercury is retrograde, some astrological adherents advise taking measures such as allowing more time for travel, backing up important computer data and not making formal legal agreements until Mercury turns direct again. In general astrological terms, Mercury is seen to influence travel, writing, commerce and petty crime. The retrograde period may also be a time for the advent of fated events.