All of the planets except the Sun and Moon appear to move backward from time to time. This movement is called retrograde motion and is an illusion caused by the Earth overtaking another planet's speed or motion. But is there more to this than just the scientific explanation? Of course there is. The universe is rich with symbolism and meaning, both hidden and apparent. It is no coincidence that the Sun and Moon which have no retrograde movement rule only one sign each. Nor is it a coincidence that the other planets which have forward AND retrograde movement rule two signs each. When a planet is moving forward in its natural easterly course through the zodiac it is expressing in its natural or true rulership sign mode, whereas when it is in retrograde or westerly motion it is expressing in it's substitute or night rulership mode. Mars in forward motion, for example, is expressing in its natural Arian mode whereas Mars in retrograde motion is expressing in its unnatural or substitute Scorpion mode. Below is a list of the planets and their sign expression modes for forward and retrograde motion... forward motion retrograde motion Sun Leo none Moon Cancer none Mercury Gemini Virgo Venus Taurus Libra Mars Aries Scorpio Jupiter Sagittarius Pisces Saturn Capricorn Aquarius Uranus Aquarius Capricorn Neptune Pisces Sagittarius Pluto Scorpio Aries So when Mercury is transiting in forward or natural motion through the zodiac, all communications activities run fairly smoothly or as they should(Gemini rulership), but when Mercury goes retrograde snags, problems, or delays occur(Virgo rulership). It's the same with the other planets ruling more than one sign each. The forward motion is associated with the planet's natural or positive qualities while the retrograde motion is associated with the planet's negative or unnatural qualities.