The Planets

Ten Functions, Not Ten Objects

A natal chart treats each planet as a job rather than as a thing in space. The Sun is the job of being someone in particular; the Moon is the job of settling; Mercury is the job of processing information. The sign a planet occupies describes the style it does that job in.

This is why a chart says more than a sun sign can. Ten functions distributed across twelve signs produces a specific arrangement, and most of the times somebody says astrology does not describe them, they are reading one function out of ten.

The Sun and Moon are called planets throughout, which is astronomically wrong and traditionally standard. The older term is luminaries, and it is worth knowing because older texts use it constantly.

The Fast Five

Mercury, Venus and Mars, plus the two luminaries, move quickly enough to differ noticeably between people born weeks apart. These are the placements that describe an individual rather than a cohort.

Mercury never strays more than about twenty-eight degrees from the Sun, so it sits in the same sign as your Sun or in one of its neighbours — never anywhere else. Venus is bound within roughly forty-eight degrees, which allows two signs either side.

Mars runs on a two-year cycle and spends six or seven weeks in a sign, sometimes far longer when it turns retrograde. It is the slowest of the personal bodies and the boundary between the individual layer and the generational one.

The Slow Five

Jupiter takes about twelve years to circle the zodiac and Saturn about twenty-nine. These two are called social planets because they move slowly enough to describe a cohort and quickly enough to still say something about a person.

Uranus, Neptune and Pluto take between eighty-four and roughly two hundred and fifty years. Everyone born within several years of you shares those placements, which is why they describe a generation and why their house position matters far more than their sign.

The outer three were unknown to classical astrology, all discovered after 1780. The tradition absorbed them and assigned them rulerships, but they sit on top of a system that was complete without them — worth remembering when weighing how much confidence to place in their readings.

Rulership

Each sign has a ruling planet, and a planet in the sign it rules is considered to operate at full strength. Mars rules Aries, Venus rules Taurus and Libra, Mercury rules Gemini and Virgo, and so on around the wheel.

The classical scheme used seven bodies for twelve signs, so five planets ruled two signs each. Modern practice reassigned three of those doubles to the outer planets: Scorpio to Pluto, Aquarius to Uranus, Pisces to Neptune.

Both schemes are still in use and neither has won. Traditional astrologers keep Mars on Scorpio and Saturn on Aquarius; most modern readings use the newer assignments. Where a chart reading surprises you, checking which scheme it used is often the explanation.

Apparent Backward Motion

Every planet except the luminaries appears at times to reverse against the fixed stars. Nothing actually reverses — the effect comes from two bodies orbiting the Sun at different speeds, the way a slower car seems to slide backwards as you pass it.

How often varies enormously. Mercury turns three or four times a year for about three weeks; Venus roughly every eighteen months; the outer planets spend several months of every year retrograde, which is common enough that no tradition treats it as an event.

The traditional reading is inward rather than adverse: the function turned toward review instead of initiation. A retrograde Mercury in a birth chart is not a defect, and is frequently described as thinking that runs internally before it runs out loud.

Putting Them Together

A chart is read as a set of relationships, not a list. Where the planets fall relative to each other — the aspects — determines whether two functions cooperate or interfere, and that is usually more informative than either placement alone.

The luminaries carry the most weight, the personal planets next, the outer planets least unless they sit on an angle or aspect something personal tightly. A generational Neptune placement that touches nothing means considerably less than a Mars in the tenth house.

None of this predicts events. The planets describe functions and dispositions, and every claim on these pages should be read as a description of temperament rather than as a forecast of what will happen to anybody.