What does retrograde mean in astrology?
A planet is retrograde when it appears to move backwards through the zodiac, as seen from Earth. Nothing actually reverses: Earth is overtaking an outer planet, or being overtaken by an inner one. Every planet except the Sun and Moon does it. Mercury retrograde, about three times a year, is the famous one.
An illusion of the overtaking lane
Most of the time the planets drift eastward through the zodiac. Every so often one stops, slides back west for a few weeks or months, stops again and carries on. Mars, for instance, traces a loop against the stars roughly every two years. It never actually turns round: Earth, moving faster on its inside track, overtakes it, and from here it looks as if Mars is going backwards. 1
The word is Latin for stepping backwards. The moments where a planet seems to stand still before reversing are called stations. 2
Mercury, the fastest planet, does this about three times a year for around three weeks; Venus every year and a half or so; the outer planets for several months of every year.
Inner and outer planets look retrograde for opposite reasons. Mars, Jupiter and the rest seem to reverse when Earth overtakes them. Mercury and Venus, which orbit inside us, seem to reverse when they swing round the near side of the Sun and overtake Earth. A retrograde outer planet is opposite the Sun in our sky and at its closest and brightest, which is why Mars looked so large in August 2003. 1
Modern astrologers also talk about the shadow: the stretch of zodiac a planet crosses three times, once going forward, once back during the retrograde, and once forward again.
What astrologers make of it
Traditional astrologers read a retrograde planet as a sign of delay, return and reversal. In horary astrology, William Lilly took a retrograde planet as a sign that a lost thing would come back, or that a traveller would return to where they started. 2
Mercury retrograde has become a cultural phrase in its own right, blamed for missed emails, lost keys and crossed wires, because Mercury is the planet of messages and travel. A retrograde planet in a birth chart is read more gently, as a planet that works inward or second time round.
How the machine checks it
Calculated facts only, worked out the same way the machine does it.
- For your birth date, the machine checks the speed of Mercury, Venus, Mars, Jupiter and Saturn along the ecliptic. A negative speed means the planet was retrograde.
- The placements table marks retrograde planets with Rx.
Where the idea comes from
Era by era, with sources. More in the Reading Room.
- Ancientc. 700 BCE onwardsBabylonian astronomers at the Esagila temple keep the Astronomical Diaries, a running record of what the sky did night by night, planets included. 3
- Classical2nd century CEPtolemy writes both an astronomy, the Almagest, and an astrology, the Tetrabiblos; his astrology takes the planets as they appear from Earth, loops and all. 4,5
- 1600s1647William Lilly's Christian Astrology gives retrograde planets meanings of return, delay and sudden reversal. 2
- Today2003NASA photographs Mars tracing its retrograde loop as Earth passes it. 1
Common misconceptions
“A retrograde planet really moves backwards.” It only appears to, from Earth. Every planet keeps going the same way round the Sun. 1
“The Sun and Moon go retrograde too.” Never. Only the planets do, because only they are seen from a moving Earth that overtakes or is overtaken.
Questions people ask
How often is Mercury retrograde?
About three times a year, for roughly three weeks each time.
What does Rx mean?
The usual abbreviation for retrograde in a chart table.
Can I be born with a retrograde planet?
Most people are. At any time it is common for one or more planets to be retrograde.
Sources
- Retrograde Mars, NASA Science, Astronomy Picture of the Day, 16 December 2003. Read on .
- Retrograde, Skyscript, Glossary of Astrological Terms (Deborah Houlding). Read on .
- Alexander Jones, The Horoscope Casters (Archaeology Odyssey 3.6, 2000), New York University Faculty Digital Archive. Read on .
- Ptolemy (by Alexander Raymond Jones), Encyclopaedia Britannica. Read on .
- Ptolemy, Tetrabiblos, LacusCurtius, University of Chicago (Loeb Classical Library translation by F. E. Robbins, 1940). Read on .