The Saturday Essay: Our ancient fascination with the sky at night

Heavenly objects do not have to be spectacularly brilliant for Wise Men to find them intriguing

TWO THOUSAND years after it was first seen by the Wise Men, astronomers are still arguing about the Star of Bethlehem. They suggest many explanations for this herald of the birth of Christ: a comet, the birth or death of a star, a conjunction of planets, an apparent hesitation in a planetary orbit, or even the sighting of the then-unknown planet Uranus.

One little-known fact is that the star was probably not the brilliant object portrayed on Christmas cards; it appears that King Herod and all his "chief priests and scribes" missed it. St Matthew did not use the adjective "bright" to describe it in his Gospel. Only in the early, less reliable, Christian literature does the star dazzle.

Heavenly objects did not have to be brilliant for the Wise Men to find them fascinating. The Magi attached a significance to cosmic events and structures that is quite alien to the thinking of their modern counterparts. Their perspective is highlighted by the translation of the Greek word "magi". The Authorised Version reads this as "wise men" but the New English Bible opts for "astrologers". Like good anthropologists, we must try to see the heavens through ancient eyes and minds to understand why this star was so significant in the Magi's Babylonian society.

The Star makes one of its rare biblical appearances in the Gospel according to St Matthew 2:1-12, which states that: "In the time of King Herod, after Jesus was born in Bethlehem of Judaea, wise men from the East came to Jerusalem, asking, `Where is the child who has been born king of the Jews? For we observed his star at its rising, and have come to pay him homage.'" Some theologians dismiss this reference to the star as a story made up to satisfy the Old Testament prophecy that "A star shall come forth out of Jacob and a sceptre shall rise out of Israel". Fulfilment of such a prediction would have provided succour for the faith.

Matthew's Gospel is full of references to the Old Testament, yet there is no such "fulfilment statement" regarding the star. If we conclude, then, that this heavenly apparition was real, rather than something cooked up to satisfy an Old Testament prediction, what did the Wise Men see?

Interpreting the meagre star evidence is tricky. When it comes to astronomy two millennia ago, there was no physical perspective and no astrophysics; the idea that planets differed from stars had not occurred to people. Instead, they were concerned with the relative position and motion of these points of light. Identifying the star would also be easier if we knew when Jesus was born. Then we could use a computer program to extrapolate from what we can see of the heavens today to what the Wise Men saw of them on that historic night. However, we don't have a precise date for Christ's birth.

Working on the assumption that the period in which the birth of Jesus took place is known - between 4BC and 7BC, some time around September or March - we can draw up a shortlist of candidates for the Bethlehem star. As long ago as AD248, Origen (Origenes Adamantius), the celebrated Christian writer, teacher and theologian, suggested that the Bethlehem star was a comet. Perhaps it was the "broom star" (sui-hsing) - so called because the comet's tail appeared to be sweeping the sky - that was described in 5BC by Chinese astronomers and recorded in the official history of the Han dynasty.

The Magi had the knowledge and cultural influences that would motivate them to chase the comet. In classical literature, the Magi are depicted as a religious group skilled in the observation of the heavens. From the fourth century BC, Babylon was the centre of astronomy in the known world and the Magi were important members of the Babylonian royal court in Mesopotamia. Moreover, Babylon had contained a thriving Jewish colony since the time of the Exile in the 13th century BC, so that the Jewish prophecies of a saviour king, the Messiah, may have been well known to the Magi.

Why did the Wise Men follow the star? Comets were then associated with great rulers, and the Magi were known to have visited kings in other countries. Not everyone agrees. Critics point out that Ptolemy, the second-century astronomer/ astrologer from Alexandria, associated comets with misfortune.

How did the comet direct the Magi to Bethlehem? Given the model of the heavens that then prevailed, comets would have been regarded by the Magi as being below the "heavenly spheres" containing the stars, planets, and so on. Colin Humphreys, of Cambridge University, explains how the Magi might have thought of the comet as hanging over a given spot, particularly if it was low in the sky and its tail was oriented vertically. This interpretation vividly fits Matthew's account: "Lo, the star, which they had seen in the east, went before them, till it came and stood over where the young child was."

There has, however, been some debate over whether the Chinese records imply movement typical of a comet. Some British astronomers have suggested that the Chinese mistakenly categorised the object as a broom star when it was in fact a "guest star", the thermonuclear flash of a nova, from the Latin nova stella, or "new star". This theory dates back a long way, perhaps even to a hint in De Vero Anno, written in 1614 by the great astronomer Johann Kepler. A few such novas appear each year, when a faint, usually unseen, star brightens by a factor of 10,000 or even 1,000,000. These outbursts are thought to occur in a binary, a pair of stars, when gases from the larger member fall into the smaller member, triggering a nuclear conflagration.

However, the same reasons that make the comet an attractive candidate for the Bethlehem star tend to disqualify the nova. Matthew 1:9 suggests that the object was later visible in the south, and a nova would not have moved that much. The location is also an unlikely one for a nova, given that the Bethlehem star appeared well away from the disc-like plane of our galaxy, which is lush with stars - its hazy cross-section is seen in the sky as the Milky Way - and likelier to be a stellar nursery.

But the objective perspective of a modern astronomer may be an inadequate one from which to hunt for the Bethlehem star. We need to understand who the Wise Men were and how they interpreted signs in the heavens. Astrology was widely practised throughout the Roman world, especially in that part of the Near East that included Judaea, and the Magi, with their detailed knowledge of the night skies, would have been unlikely to have been impressed by a routine event such as the appearance of a shooting star. They might, however, have been moved by something in the night skies that would seem unremarkable to a modern astronomer. This is best understood by looking back at the common origin of astronomy and astrology.

Before the 17th century, there was not the sharp dichotomy that we see today between astrologers (who always spout ambiguous rubbish) and astronomers (who sometimes do). At the root of both disciplines is our ancient fascination with the night sky. A holy man's knowledge of the heavens conferred an ability to foretell the future, guiding him through the seasons, showing when to harvest and when to move herds. It also helped him to predict notable events such as a solar eclipse or the flooding of rivers such as the Nile. In this restricted sense, knowledge of the heavens illuminates our destiny. This, however, is a far cry from the astrologer's supposed art of judging the occult influence of the stars on human affairs.

Woe betide anyone who confuses astronomy and astrology today. But when the Wise Men gazed at the heavens, they glimpsed something of their destiny. Once we accept that the Magi had an astronomer's interest in the details of the night sky, spiced with the astrologer's fascination for what these details might say about human affairs, it becomes apparent they may not have seen a star at all, or indeed a cut-and-dried astronomical object, but an unremarkable cosmic event with remarkable symbolism.

This fascination with cosmic symbols underlines one clear difference between the Magi and the chief priests: astrology was practised in Babylonian society, whereas it was forbidden in Jewish society, according to Deuteronomy 4:19 ("lest thee corrupt thyselves... lest thou lift up thine eyes unto heaven, and, when thou seest the sun, and the moon, and the stars, even all the host of heaven, shouldst be driven to worship them, and serve them"). That Herod was unaware of the star until the Magi informed him of its significance adds weight to this argument.

If we accept that many Bethlehem-star suggestions do not take into account the mindset of the Wise Men, what kind of astrology was practised in the Near East during the reign of King Herod? Michael Molnar from Rutgers University in Piscataway, New Jersey, has studied Greek astrology as used throughout the Roman world, including Mesopotamia and Babylonia, and drawn his own conclusions: "By my theory, Jesus would have been 2,000 years old on 17 April 1995". His candidate for the Star of Bethlehem is an event that took place on 17 April 6BC: a double occultation of Jupiter by the Moon, when our closest neighbour moves in front of the giant planet. Molnar's studies have suggested that this event, though of little significance to a modern astronomer, was "brilliant" in an astrological sense.

Michael Molnar notes that astrological signs appeared on ancient coinage, notably from Antioch, the capital of the Roman province of Syria. On one side of each coin was a bust of Jupiter. On the other, Aries the Ram gazed back at a star. Molnar now believes that the coins commemorate the annexation of Judaea by the Romans, which suggests that the Romans were aware of important astrological portents involving Judaea. He considers it likely that what he calls "the great portent" of 17 April 6BC was very much on their minds - the Romans were looking for proof that a Roman, not a Jew, had fulfilled the messianic prophecy. Aries appeared on the coins because it was linked to Judaea in contemporary symbolism: Ptolemy mentions that Judaea is under the spell of Aries.

Molnar's argument needed another ingredient - the presence of a heavenly body to symbolise the birth of a king: "My initial search for a regal `star' centred on the star of Zeus, namely the Planet Jupiter, which invariably played the central role in horoscopes that had regal implications". To identify an astrological portent involving Jupiter, he focused on lunar occultations. These are "bull's-eye" conjunctions in which the Moon's disc obscures the planet. Examining the likely time frame, Molar found only two that took place in Aries and thus in Judaea, occurring on 20 March 6BC and 17 April 6BC: "During the second occultation, Jupiter was precisely `in the east', an astrological terminology that Matthew uses to describe the Magi's star". The heavens on 17 April 6BC produced impressive astrological portents: "If we recreate a horoscopic chart for [this date]," writes Molnar, "we find unmistakable indications pointing to the birth of a king of Judaea. I believe that a horoscope of that day was incredibly ominous - truly messianic".

The mystery of the Star has been solved. Perhaps not. David Hughes of Sheffield University, for one, believes that such occultations took place too regularly to be of great astrological significance. He is struck by the rival idea of a triple conjunction and argues that the Bethlehem triple conjunction was Jupiter, Saturn and the constellation of Pisces. The regal aspect came from Jupiter, while Saturn stood for both the principle of justice and the land of Palestine. Pisces was the sign of the zodiac that represented the land of Israel. This conjunction, claims Hughes, signified a potent brew of divinity, kingship and righteousness involving the Jewish people and the Promised Land: "Putting it crudely, that is why the Wise Men went for Jerusalem."

The Magi could have figured out the details of the triple conjunction well in advance. They could have watched the first conjunction from Babylon in May of 7BC, but delayed travelling until the end of the long, hot summer. On their way to Jerusalem, they could have witnessed the astrologically important moment when Jupiter and Saturn were rising at the instant of sunset.

As interpreted by David Hughes, the passage rendered in most translations of the Bible as "We have seen his star in the east" has a more specific meaning, namely "We have seen his star rising in the east as the Sun was setting". If this explanation is correct, the only thing that is miraculous is that the Magi noticed the "star" and made the arduous trek to witness, as they said, the appearance of a new king for the Jews. This suggests the real Christmas should be celebrated some time around the month of September, to reflect the events that took place in 7BC. However, given the patchy evidence, the Star of Bethlehem debate will no doubt continue.