Mercury

What Mercury represents

Mercury is the function that names, sorts and passes things on. It shows how a person thinks: by intuition or by method, quickly or taking their time, in pictures or in lists. It also describes how they speak and listen, what sparks their curiosity, how they learn and how they cope with the unexpected. It is the messenger planet: it sets in motion what would otherwise stay locked inside each person.

Mercury rules two signs. In Gemini, an air sign, it is quick, playful and drawn to anything that can be connected; in Virgo, an earth sign, it becomes precise, practical and attentive to detail, and tradition also considers it exalted there. It is in detriment in Sagittarius, where thought takes the wide view at the risk of skimming the surface, and in Pisces, where it works through impressions more than reasoning, a sign that is also the place of its fall. Its gift is a talent for exchange; its excess, scattered attention or chatter that steers clear of what matters.

Its rhythm in the sky

Mercury always keeps close to the Sun: it is found in the same sign or in a neighbouring one. It completes the circuit of the zodiac in roughly a year, at a very uneven speed, and generally spends around three weeks in a sign. Because its sign is bound so closely to the Sun’s, it is mostly its house and its aspects that make it personal to each chart.

Three times a year or so, Mercury seems to stop and run backwards for about three weeks. This retrograde motion is an optical effect, produced by the different speeds at which the Earth and the planet travel around the Sun. It can keep Mercury in one sign for two months or a little longer. In a birth chart, a retrograde Mercury is often read as a mind that turns back on itself and lets ideas ripen inside before voicing them, with nothing unfavourable about it in itself.

Mercury in conversation

Mercury reveals how a person makes themselves understood and what they need in order to feel heard. Some need to talk to find out what they think; others need a moment of silence before they answer. Some enjoy a debate; others experience contradiction as an attack. In a couple, a friendship or a shared piece of work, many frictions have less to do with substance than with these different rhythms, and simply recognising them is often enough to calm a discussion that was turning sour.

In synastry, Mercury’s contacts show whether two people find it easy to talk. When one person’s Mercury touches the other’s Sun, Moon or Mercury, conversation often has natural ground to stand on: each catches the other’s meaning before the sentence is over, and both want to tell each other things. A tense contact, on the other hand, can produce lively, stimulating and sometimes prickly exchanges. Mercury’s contacts do not make a relationship on their own, but they weigh heavily on everyday life, where everything gets talked through.

To go further

• Liz Greene and Howard Sasportas, The Inner Planets (1993)