The star of Bethlehem

It’s almost Christmas, so it’s a good time for a look at something interesting but not so serious. What was the star that the wise men followed to lead them to where the baby Jesus was in Bethlehem?

Background facts

• The story of the wise men and the star is only told in Matthew’s gospel, and a few very embellished and much later stories that are based on Matthew.
• The word “magi”, traditionally translated as “wise men”, should probably be understood as “astronomers” or “astrologers” (the two weren’t all that different back then).
• Historians generally date Jesus’ birth to between 7 BCE and 4 BCE, based on Herod, who historians believe died in 4 BCE, still being alive at the time. (The reason he wasn’t born in year 0 is (i) there wasn’t a year 0, and (ii) calendar calculations centuries later were inaccurate.) However a few people hold out for a later date for Herod’s death and Jesus’ birth.
• Because of difficulties in reconciling the birth accounts in Matthew and Luke, and the nature of these stories, many historians regard all or part of the accounts as theological rather than historical, though many others regard them as complementary factual accounts.

Possible explanations

Pious fiction

Sceptics and more liberal christians believe that the story of the wise men and the star never happened, and thus requires no explanation. It is based on the historians’ doubts, but ignores the fact that legends often have some factual basis, and so there may have been some astronomical phenomenon at that time.

This is an easy position to hold, but not much fun, so let’s keep looking.

Astronomical event

This is probably the most popular hypothesis, as people have proposed a comet, a supernova or nova, a conjunction of planets, or a sequence of such events. Astronomers are able to determine where planets were at various times, but comets and nova are more difficult to identify. Some of the best researched proposals include:

• Early astronomer Johannes Kepler suggested a conjunction of Jupiter and Saturn in 7 BCE, but later abandoned the idea as the two would not have been close enough to appear as one object. This, and other planetary conjunctions, could also have had astrological significance (see below).
• Some have suggested a comet, for example a comet reported by Chinese astronomers in 5 BCE. But comets were generally seen as harbingers of doom, and unlikely to be interpreted as signifying the birth of a king. Besides, the object reported by the Chinese was more likely a nova.
• Cosmologist Frank Tipler argues, based on where the star was seen, for a supernova in Andromeda. His hypothesis explains why Herod was unaware of the star, and has the advantage of being testable – he identifies its size and the location in Andromeda that should be searched. But at present it remains unverified (to my knowledge).

If any clearly visible astronomical event was the correct explanation, I would think it would have to be Tipler’s suggestion. But all these suggestions seem to fail because if the star was clearly visible, why didn’t Herod know about it? And how does a celestial body “stop” over Bethlehem?

Astrological events

If a clearly visible astronomical event fails the test, perhaps the star was not clearly visible, but observable by those who knew what to look for and how to interpret it (i.e. astrologers). Faint nova, planetary conjunctions, and the appearance of certain planets in certain constellations all may meet this criterion. For this reason, I feel that these explanations are the most likely.

• Even if Jupiter and Saturn were clearly separated in 6 or 7 BCE (I have seen both years suggested), their appearance together in the constellation of Pisces might have been seen as important by astrologers. Jupiter was apparently seen as the royal planet, while some say Saturn and Pisces were associated with the Jews, but others say this isn’t so.
• Astronomer Michael Molnar points out that Jupiter was occulted (= eclipsed) by the moon twice in the constellation of Aries in 6 BCE, and he argues that it is Aries, not Pisces, that was the constellation associated with Palestine. Planets normally move slowly through the “fixed” constellations, but under some circumstances (when the faster-orbiting earth is “catching them up”), outer planets like Mars and Jupiter can appear to stop, go into “retrograde motion” for a few months, stop again, and then resume their forward movement. This occurred with Jupiter later in 6 BCE, and the second stationary period would have been (Molnar argues) when the Magi would have seen it “stopped” over Bethlehem. Thus Molnar’s hypothesis explains most of the difficulties, but critics say that Jupiter at this time was close to the horizon and therefore difficult to see.
• Mark Kidger takes several of these ideas and forms them into one hypothesis. He suggests that the Magi were alerted by a sequence of events that included two planetary conjunctions or near misses in 7 & 6 BCE, the movement of Jupiter in 5 BCE and finally the nova reported by the Chinese in 5 BCE, which was the actual star the Magi followed.

Miraculous sign

Christians are free to believe that there is no natural explanation for the star, for it was a special miraculous sign. Like the sceptical response, this conclusion cannot be proven or disproven, but I’m inclined to think that God more often works through natural means.

So which is the star of Bethlehem?

Of course no-one can know. But since this is a less serious and more speculative post than usual, I’m going to make a guess.

I think both the sceptical and miraculous responses are not based on evidence, but on certain a priori commitments (call it faith or disbelief). With so many possible natural hypotheses available, it seems foolish to say they couldn’t be true, as these two views do. So I’m going for a natural explanation.

I don’t favour the astronomical explanations (though if Frank Tipler’s predictions are verified, his hypothesis would have merit). I don’t think they explain why Herod and others didn’t notice the sign in the heavens, and they don’t explain how the star stopped over Bethlehem.

So I believe the astrological explanations are to be preferred, and Molnar’s hypothesis seems to explain everything best of all. I’ll go with that. But I agree with how one reviewer concluded:

Is Molnar’s case airtight? No. Is it convincing? Yes. Does it matter if he’s right or wrong? Absolutely not.

Of course, even if Molnar’s hypothesis is true, it doesn’t mean that all of Matthew’s story is true, though I suppose it makes that a little more likely.

Further reading

• Wikipedia on Star of Bethlehem.
• Martin Gardner reviews the evidence.
• Revealing the Star of Bethlehem, my favoured hypothesis.
• A review of Molnar’s and Kidger’s hypotheses.
• NT Wright on Suspending scepticism: History and the Virgin Birth.

Photo Credit: hoyasmeg via Compfight cc