by Duncan Lunan

As this is the last of the planned ‘Beginners’ Astronomy’ articles, and it’s scheduled to appear on Christmas Day, this seems an appropriate subject to end with.  Discussion is somewhat limited because the Star appears only in the Gospel According to St. Matthew, and his account is brief. 

“Now when Jesus was born in Bethlehem of Judaea in the days of Herod the king, behold, there came wise men from the east to Jerusalem, saying, ‘Where is he that is born King of the Jews?  For we have seen his star in the east, and are come to worship him.’… Then Herod, when he had privily called the wise men, inquired of them diligently what time the star appeared… When they had heard the king, they departed;  and lo, the star, which they saw in the east, went before them, till it came and stood over where the young child was.  When they saw the star, they rejoiced with exceeding great joy.”

Already there are problems with this account as it has come down to us, starting with the fact that Herod died in 4 B.C., and in March or April at that.  Probably that contradiction stems from miscalculation of the date of the Nativity.  It’s generally agreed that the wise men would have been astrologer-priests from Mesopotamia.  They’re usually depicted riding camels  (Fig. 1), but that’s a later addition because there were no camels in the Middle East at the time. 

Furthermore, if the shepherds were ‘watching their flocks by night’, probably it was to protect newborn lambs from predators in early spring  (Larry Sessions and Deborah Byrd, ‘Was the Christmas Star Real?  What Was It?’, EarthSky, online, December 23^rd, 2022.)  Matthew’s text has to be read as ‘we have seen his star when we were in the east’, because if the Star had been in the east when they first saw it, they wouldn’t have followed it towards Jerusalem.  In fact, the movement of the Star as described can’t be reconciled with any natural heavenly body, and most Christian astronomers have been happy to accept it as a purely supernatural or symbolic event.  But nevertheless, attempts to find an explanation for it continue.

In his essay on it in The Challenge of the Spaceship, Sir Arthur C. Clarke began with the planet Venus.  It was in the evening sky when he was writing, near Christmas, and as his opening statement was true for approximately one Christmas in three, he let it stand.  (This year Venus has just appeared in the evening sky, and has been seen from countries near the Equator, but isn’t likely to appear in this latitude until January.)  The problem in matching it with Matthew’s account is that if Venus was above the horizon at sunset, it would have set soon afterwards  (Fig. 2).  And of course, the Mesopotamian priests were very familiar with Venus, who had been personified as Inanna for thousand of years and was by that time identified with Ishtar.

Sir Arthur’s second idea was that it might have been a comet, upright like an arrow in the western sky and pointing into Judaea  (Fig. 3).  Bright comets do appear in the historical record, often with mystical significance, like the ‘drawn sword’ which David saw over Jerusalem  (I Chronicles 21:16), probably a comet in Chinese annals for the 970s or 960s BC;  and ‘Lugh of the Long Arm’, in Irish annals and others c.540 AD – both of them related to global climate turndowns and suggesting that the comets actually hit the Earth.  Striking though the image is for the Star of Bethlehem, again such a comet would have set soon after sunset, and comets were familiar to the ancient astrologers, so one that made so big an impression would have to be very big or very close to the Earth, and there’s nothing like it in the detailed astronomical records of Japan, China or Korea at the time.

As I explained in ‘Howlers in Space Part 2  (ON, Oct. 25^th 2022), few terms in astronautics are more misunderstood than ‘synchronous orbit’.  It can only be achieved over the equator of a planet or moon, and only at an altitude where the orbital period precisely matches the rotation of the body.  For Earth, that altitude is 22,000 miles.  In Star Trek the Enterprise is repeatedly in ‘synchronous orbit’ anywhere from the equator to the poles  (Fig. 4), and Sydney Jordan took artistic license to do the same in his Lance McLane comic strip for the Daily Record in the 1970s and 80s.  But anything in synchronous orbit at the Nativity would be over the Equator, not over Palestine.

My late colleague Alan Evans  (obituary, ON, May 22^nd 2022)  was particularly interested in what he called ‘Tau Ceti orbit’.  If a starship enters the Solar System and makes orbit around the Earth without any plane change manoeuvres, with respect to the Sun or the Earth, then it will be in an orbit inclined to the Equator by an angle equal to the declination of its origin star, and that declination will mark either the furthest north or furthest south point at which the starship passes vertically overhead.  ‘Tau Ceti orbit’ looked to be significant in relation to the radar-reflecting properties of the Great Pyramid, when it was constructed.  Seen from Tau Ceti, our Sun is a star in the constellation Boötis, and in a journey from there to here at near the speed of light, epsilon Boötis would be the prime navigational reference  (‘Epsilon Boötis Revisited’, ON, May 29^th 2022).  There’s a highly speculative interpretation of the Vision of Ezekiel, which I’ve never published, which could be taken to be a simulation of such a journey.

To say the least, this is all pure speculation.  But in the circumstances, it’s interesting that a starship in Tau Ceti orbit circa 0 BC would be overhead on the latitude of Bethlehem when at its furthest north.  To paraphrase David Lindsay in Voyage to Arcturus, ‘The music was not playing for you, my friend…’  Some people have got very upset when I’ve quoted that, but there’s no need.  Such an orbiter would have been overhead only momentarily, wherever and at whatever moment of day or night it came to its furthest north, and would have been in continuous motion, immediately passing on.

We also looked at the possibilities of ‘tundra’ orbit, into which the International Ultraviolet Explorer was launched in 1978  (‘Space Observatories’, ON, December 11^th 2022).  Launched into  orbit with a 24-hour period, and a high inclination to the Equator, the IUE passed over the nations participating in the project at regular intervals and removed the need for the spacecraft to carry a taperecorder, always a weak point in long-term missions.  Alan and I looked at the possibilities for a number of historic sites, but eventually realised that for any three points on the Earth’s surface, we could always find a combination of inclination and orbital period which would bring a spacecraft over them in succession – making all such arrangements indistinguishable from coincidence.

Sir Arthur’s next and last suggestion, for which he’s best known, was the Star could have been an exploding star.  Picturing the shells of light from such an event expanding through the Galaxy, he wondered who else might have seen it in their skies before 0 BC, and who else might be seeing it now.  ‘Did it bring them good tidings, or ill?’ 

When he was writing, the distinctions had yet to be made between novae, which are surface events in red giant-white dwarf binary systems, Type 1 supernovae, which are similar events in red dwarf-neutron star pairs, and Type 2 supernovae, which are core explosions as all exploding stars were originally thought to be.   It was thought that stars like the Sun could go nova, as the Sun does in Sir Arthur’s first published story, ‘Rescue Party’  (1946).  Arthur followed the essay with a short story, ‘The Star’, which he described as ‘written in a particularly intense episode of emotion’.  His central character is a Jesuit astronomer on an expedition to a supernova remnant, where an outlying surviving planet bears a memorial to the inhabitants of an inner planet which has been destroyed.  Dedicated to science and the arts, they were clearly on a moral and intellectual plane higher than our own, and on the return journey, the priest has calculated the date of the explosion.  “Yet, oh God, there were so many stars you could have used.  What was the need to give these people to the fire, that the symbol of their passing might shine above Bethlehem?’

The story was published in 1955 and has been multiply reprinted, as well as being televised at Christmas 1985.  Harrowing as it is, the main cause for concern has been removed.  We now know that for core explosions, stars need to be more massive than ‘Chandrasekhar’s Limit’, 1.4 times the mass of the Sun.  To make a star like the Sun explode, a trigger like a high-energy laser beam would be needed  (Fig. 5.)   Prof. Geoffrey Burbidge described a way to do it with a 10¹² kilowatt gamma-ray laser, using a thousand times more energy than the power consumption of 20^th century civilisation  (Nature, 1961;  Carl Sagan and I.S. Shklovskii, Intelligent Life in the Universe, 1966).  But he was thinking of industrial operations on a galactic scale, where any star not supporting intelligent life would be more suitable. 

In any case, the Far Eastern records contain no such event.  When I was researching Man and the Stars in 1973 I made my own search of the records that were then accessible, and others have searched far more thoroughly since without finding any candidates for the Star.   There was a supernova in 5 BC, recorded over a period of two months in China, but it was in Capricornus, too far south to ‘lead’ anyone from Mesopotamia to Palestine  (Larry Sessions and Deborah Byrd, op cit).

In a calmer mood, the supernova 1987-A in the Large Magellanic Cloud prompted Dr. Iván Almár of Budapest to suggest that we should look ‘upstream’ for any civilisations near the line of sight, and we ourselves should signal ‘downstream’ to attract the attention of any later recipients who would be watching the event in their own time-frame.  It’s a good idea, but so far there hasn’t been another bright supernova to try it out on.

The current favourite for the Star is not a single object, but a succession of planetary conjunctions between 7 and 5 BC, in the constellation Pisces, repeating a supposed triple conjunction in Pisces three years before birth of Moses, making Pisces the national constellation of Israel.   In 150 BC the Vernal Equinox moved from Aries into Pisces, and as the letters of ‘Jesus’ make a fish shape in Greek, the fish became a secret symbol in early Christianity.   Although newspaper horoscopes still give Aries as the first sign of the Zodiac, the Vernal Equinox has been in Pisces throughout the Christian era, and has not yet reached Aquarius, Hair notwithstanding.

Conjunctions are not uncommon, as witness the many I’ve given notice of in ‘The Sky Above You’, but multiple ones and close ones are taken seriously by astrologers, being blamed for the Black Death, for instance.  There were three Jupiter-Saturn conjunctions in Pisces over 11 months, first on 27^th May7 BC, then 6^th October, thirdly on 1^st December.  In 6 BC there were occultations of Jupiter by the Moon on March 20^th and April 17^th, the latter possibly coinciding with the Wise Men’s visit to Herod.  There were conjunctions of Jupiter and Venus on May 24^th and August 12^th of 3 BC, but they were after the death of Herod in 4 BC.

However, 6 BC saw a Jupiter-Saturn-Mars conjunction, a once-in-805 year event.   My colleague Chris O’Kane has a very interesting thesis about Mars, namely that the planet is represented in Egyptian mythology by the god Horakti  (‘The Horus of the Horizon’), and the king’s journey through the Underworld represents the journey of Mars around the Zodiac, from opposition to opposition, beginning and ending at the right hand of Osiris, represented by Orion.  (Chris O’Kane, ‘The Identity of the King and the Sun God’, Ancient Egypt, October-November 2005.)  In 5 BC and 3 BC, the heliacal rising of Mars  (first visibility before sunrise)  occurred in the constellation Cancer, within the Open Cluster of Praesepe, the Beehive, also known as the Manger.  (Fig. 6.  I pointed out a possible connection between the Beehive, the Leonid meteors and the legend of Samson, in ‘Winter and Spring Stars, Part 2’, ON January 23^rd, 2022.)  If the 5 and 3 BC events had been oppositions, the retrograde  (westward)  movement of Mars would have mirrored the flight of the Holy Family from the Manger into Egypt.  It’s just a thought of my own, but maybe that part of Matthew’s account is a mangled version of a much older fragment of star-lore.