Venus is in Vacca, with logic in limbo

Astronomy and astrology are now infrequent, uneasy bedfellows.

The scientific study of stars, planets and galaxies, replete as it is with prestigious university departments, national observatories, remote satellite instrumentation and huge computers and telescopes, has little in common with the expectation that the Sun and small non-luminous orbiting bodies can influence the character and destiny of humans simply by changing their celestial positions.

It was not always so. Until the Renaissance, astrology was a great spur not only to astronomical observation but also to the generation of models of the cosmos and ephemerides. Many great astronomers, Johannes Kepler, Tycho Brahe and Isaac Newton, for example, enhanced meagre "scientific" incomes by casting horoscopes for the rich.

Sir Patrick Moore, in this delightful, light-hearted little book, approaches the topics in two ways. He is mindful of the fact that tabloid coverage of astrology vastly outweighs tabloid interest in astronomical science. Millions of individuals regularly consult newspaper and magazine horoscopes in which they find strange terms such as ecliptic, zodiac, conjunctions and massings along with exotic planets such as Venus and distant celestial places such as Aries. Moore gently introduces them to the science of the Sun and the Moon, the solar system and the zodiac.

He explains the contents of each horoscopic constellation and jokingly stresses that the nomenclatures are frivolous. One chapter illustrates the attributes of Aries, Taurus, Cancer, Leo and so forth, but notes that rams, bulls, crabs and lions do not immediately spring to mind when gazing at these groups of stars. The next chapter transforms the zodiacal constellations into Cochlea Piscatoris (the Fish Slice), Vacca Volitans (the Flying Cow), Homo Nivalis Vere Vere Horribilis (the Abominable Snowman) and others.

Moore then focuses on possible ways in which celestial happenings can influence earthly existences. Here he considers luminosities, orbits and time intervals, gravitation and tidal forces and magnetic effects.

Phenomena are sorted into two groups. One we understand. The influence of the Sun is obvious. Changes in the length of daylight and seasonal variations in temperature and growth cycles are scientifically explicable, as are the effects of tides. This "understandability" seemingly removes them from the astrological realm.

But the statistical indication that people born when the Sun is in Gemini have a propensity for science, and that Aries is the natal constellation of excellent teachers, has not been explained and is not scientifically understandable. This is astrological territory, which Moore dismisses as pseudo-science. Astrologers are accused of being adept at coincidence spotting, speedy character assessment and intriguing generalities. Moore brackets them with psychologists and psychiatrists.

Two questions are left unanswered. Why are astrologers invariably so much richer than astronomers, and why do so many millions still regularly study their astral predictions?

David Hughes is professor of astronomy, Sheffield University.