Mercury
Never more than twenty-eight degrees from the Sun, and backwards about three times a year, which is why its retrograde stretches are the best known of any planet’s.
Where Mercury is now
What Mercury stands for
Mercury stands for how a person thinks and speaks: the speed of the mind, the habit of explaining, letters, trades and arguments.
The god Mercury carried messages and looked after travellers, merchants and thieves, and the astrological Mercury keeps the whole brief: language, numbers, trade, short trips, brothers, sisters and neighbours, and the hand that writes or makes. It is read less as intelligence than as the way a mind works, fast or careful, spoken or written. Older texts call it changeable, taking on the colour of whichever planet it is closest to.
How Mercury moves
It circles the Sun in eighty-eight days, but from here it shadows the Sun and is never more than about twenty-eight degrees from it, so it takes a year to go round the zodiac. It goes backwards three or four times a year, for about three weeks each time.
That closeness is why Mercury is always in the same sign as the Sun or in one of the two either side of it.
From the Earth, Mercury swings from one side of the Sun to the other. When it is furthest east of the Sun it can be seen low in the west after sunset; when furthest west, low in the east before dawn. It always sits in twilight, which is why many people have never knowingly seen it, and the visibility page shows when it can be found.
Retrograde is an effect of viewpoint. Mercury laps the Earth on the inside, and for nineteen to twenty-five days around the time it passes between us and the Sun it appears to slide backwards against the stars. The loops come about every hundred and sixteen days: three in most calendar years, four in roughly one year in six. Mercury is retrograde about a fifth of the time, so roughly one birth chart in five has it that way, and the Mercury cycle draws each loop.
Rulership, dignity and sect
Mercury rules Gemini and Virgo.
It is also exalted in Virgo, at fifteen degrees by the old reckoning, the only planet exalted in a sign it rules. Its detriment and fall lie opposite, in Sagittarius and Pisces, with Pisces counting as both. Mercury is neither benefic nor malefic by nature: the tradition calls it common, and reads it as helpful beside Venus or Jupiter and harder beside Mars or Saturn.
Its sect changes too. When Mercury rises before the Sun, as a morning star, it counts with the day planets; when it sets after the Sun, as an evening star, with the night planets. Its joy is the first house, the house of the body and the self.
Reading Mercury by sign and by house
By sign, Mercury is read as the style of thinking and speaking: in Aries it decides fast and says so, in Capricorn it wants the structure before the conclusion. Since it can only be in the Sun’s sign or one either side, somebody with the Sun in Leo has Mercury in Cancer, Leo or Virgo and nowhere else; the Gemini page and the Virgo page describe its two signs. By house, it is read as where a person does most of their thinking, talking and dealing.
A worked example: Mercury in Gemini in the third house is in its own sign in the house of letters and neighbours, and is read as a quick, sociable mind that learns by talking. Mercury retrograde in the same place is read as that mind turned back on itself: revising, rereading, reaching the point by a longer route.
What gets confused about Mercury
Mercury retrograde is the best-known idea in popular astrology and the most exaggerated. The tradition reads the stretch as a time for going back over plans, messages and agreements; it does not say that things break. Nothing physically reverses, and every planet except the Sun and the Moon does the same on its own schedule, as the retrograde page shows.
Some astrologers also mark a shadow: the stretch of the zodiac Mercury covers three times, forwards, backwards and forwards again. Its length follows from the geometry, a couple of weeks or so either side of the retrograde itself.
Questions people ask
What does Mercury retrograde mean?
It means Mercury appears to move backwards against the stars for about three weeks, an effect of the Earth and Mercury passing each other in their orbits. Astrology reads the stretch as a time for review: going back over messages, plans, travel arrangements and agreements. It describes the planet’s motion and the tradition’s reading of it, and is not a claim that anything breaks.
How many times a year is Mercury retrograde?
Three times in most years, and four in about one year in six, because the cycle from one retrograde to the next is about a hundred and sixteen days. Each lasts roughly nineteen to twenty-five days. Taken together Mercury is retrograde about a fifth of the time, which also means about one person in five was born with Mercury retrograde.
What does Mercury rule in a birth chart?
Mercury is read as the way a person thinks, learns and communicates: speech, writing, numbers, trade and everyday dealings with siblings, neighbours and colleagues. Its sign is read as the style of the mind and its house as where that mind is busiest. It rules Gemini and Virgo, and because it stays close to the Sun it is always in the Sun sign or a neighbouring one.
Can Mercury be two signs away from the Sun sign?
No. Mercury never appears more than about twenty-eight degrees from the Sun, and a sign is thirty degrees wide, so it is always in the same sign as the Sun or in the sign on either side. Somebody with the Sun in Pisces has Mercury in Aquarius, Pisces or Aries. Venus can reach further, up to two signs away, because it strays up to about forty-seven degrees.