'Oh little gas giants of Bethlehem...'

The approach of Christmas has, yet again, prompted a scientist to consider which star led the wise men to Bethlehem. In this striking contribution to the genre, Percy Seymour concludes that the event was the "triple conjunction" of 7BC between Jupiter and Saturn. As the Earth overtakes these giant planets in their orbits of the Sun and as Jupiter in turn overtakes the more distant Saturn, an observer on the Earth sees Jupiter and Saturn dance a slow but fascinating reel in which they approach each other not once but three times - a gripping spectacle for sky-watchers.

Other investigators have identified this conjunction as a candidate for the Star of Bethlehem, but Seymour's reasons for favouring it are unexpected. With admirable pluralism, Seymour, a mainstream astronomer, looks fearlessly for links in the world of astrology. This is despite the fact that for most astronomers, astronomy and astrology parted company at the death of Isaac Newton.

Seymour's book makes extended and sometimes rambling digressions into vast areas of religion, superstition and science (several pages are devoted, for no good reason I could discern, to the Holbein painting The Ambassadors). His aim is to make the case that the Magi - "wise men" whose knowledge centred on astrology and religious lore - were attracted to Bethlehem partly by the conjunction and partly by the fact that it occurred in the constellation Pisces. To the astrologer, the appearance of the Sun in a particular constellation on the first day of spring is highly significant: at the time of Christ's birth, the "Age" of Pisces was just beginning (now it is giving way to the Age of Aquarius). To the astronomer, such a coincidence means, of course, nothing at all.

More interesting still is the method the Magi might have used to find the correct stable. The method of the nativity play -looking for the spot where the star is exactly overhead - just will not work. As Seymour points out, too, in the biblical account Herod is alerted to the birth of Christ by the Magi, rather than his courtiers, who were presumably not very interested in the conjunction. But for the astrologer, claims Percy, Pisces was associated with Bethlehem, Saturn with "the protector of the Jews" and Jupiter with kings and leaders. Moreover, the conjunction would have been at its most obvious in mid-September; September 15 7BC is the current best guess for the date of Christ's actual birthday.

So far so good. Certainly the triple conjunction theory seems more plausible than other suggestions such as comets and novae. But nothing can disguise the fact that for anyone with a positive view of modern science, there is plenty to dislike in this book. While interested to look at an astrological chart, I do not for one second expect it to tell me something about someone's life - this is a fool's errand because it is a proven failure. And then Seymour does something even more outrageous: he supports attempts to decide when people were born by extrapolating backwards from their personalities. Methodological problems seem unavoidable.

For this somewhat reduc-tionist reviewer, some aspects of The Birth of Christ went much too far, although it was undoubtedly an enjoyable read. Without recourse to the stars, we can predict that the paperback will be available in autumn 1999 for filling Christmas stockings.

Martin Ince is deputy editor, The THES.