The Circle of Little Animals

This is an auspicious time of the year.

The Sun, on its yearly circuit of the sky*, moves gradually along the ecliptic, a line which is the projection of our solar system’s disk onto our night sky. This line, the ecliptic, is also known as the zodiac, a term originating from the late 14th Century, and deriving from the Greek literally translating as “circle of little animals”. (Incidentally our word for zoo derives from the same origin).

The Circle of Little Animals

To the ancient Greeks this was indeed a circle of little animals, featuring: a ram, Ares; a bull, Taurus; Pisces the Fish; and many other well known (for all the wrong reasons) constellations. It also features three humans: Aquarius the Water Carrier, said to represent Ganymede, beloved of Zeus; and Gemini the Twins, Castor and Pollux.

The only zodiac constellation which is inanimate is Libra the Scales, taken from Babylonian astrology. The Greeks however didn’t recognise Libra; instead they thought that the stars here marked out Scorpius’ claws, which they considered to be a separate sign.

So the twelve constellations that lie along the ecliptic are most well-known due to astrology, a pseudo-science that suggests there is some significance to which constellation the Sun was in when you were born. This is, of course, bullshit.

There are so many reasons why astrology should be laughed off as pre-scientific magical thinking (no evidence, no mechanism by which it might work, inconsistent etc) but next time you meet an astrologer ask them what star sign you would be if you were born between 30 November and 18 December. If they tell you Sagittarius (if they’re a Hindu astrologer they might also say Scorpius) then tell them they are plain wrong.

On these 18.4 days of the year the Sun is wonderfully absent from the usual twelve zodiac signs, It is still there, however, gracefully moving along the ecliptic, but between 30 November and 18 December it is in the constellation of Ophiuchus the Serpent-bearer.

Ophiuchus does not appear in any astrologer’s zodiac. Back in the early days of astrology, when it was first dreamed up several thousand years ago, there were indeed only twelve constellations lying along the zodiac. Over the past few millennia however the Earth’s axis has wobbled slightly (an effect called precession) with the result that the line of the ecliptic has moved with respect to the constellations, and so an interloper, Ophiuchus, has crept in.

So celebrate all those of you born between 30 November and 18 December (one person in twenty share this star sign); you’re not a Sagittarian at all; you’re an Ophiuchan.

It’s still all bullshit though.

* the Sun, of course, does not orbit the Earth, it’s the other way around. It just looks like it does from down here…