Irish God Kings and a Nine-month Day!



Following the article in Nature by Cassidy et al (2020) there has been renewed interest in the Irish mythology surrounding the construction of Newgrange, and its legendary builder Echu Ollathir, also known as Dagda: “the Good God”. The interest stems from DNA evidence of in-breeding within members of the Irish royal family, an incidence of which is actually described within the legends. So, if we are to validate one part of a legend by modern science then we should ask: on what grounds do we dismiss all the other statements within it? Here is an analysis of some of the astronomy within those legends.


Genealogists sampled 44 genomes from remains discovered within the deep recesses of the Newgrange passage grave; one of which they identified as the adult son of an incestuous first degree (brother-sister) conception, typical of those within Egyptian royal families. [1] Remains from other nearby passage graves were also found to be close relatives of this same individual. This raises the possibility of a dynasty of elite ‘god-kings’ among the early Irish, analogous to those of Egypt. The royal remains showed a DNA profile typical of the Western Neolithic population of Atlantic Europe (light-skin and brown eyes) that expanded westward, along with agriculture, from Anatolia and the Black Sea region around 6-7,000 years ago. [2] However, other burials also showed evidence of Irish hunter gatherer DNA (darker skin and blue eyes) – indicative that some of the population had survived from the earlier Mesolithic inhabitants. [3]


The entrance to Newgrange prior to the modern reconstructions (Macalister 1931) and the unreconstructed mound of Dowth.

In the metrical Dindshenchas (place-name legends) we find origin-stories for the tombs at the Bend in the Boyne; in particular the building of the Newgrange and Dowth passage graves by the legendary kings of the Tuatha Dé Danann.


The Dagda and his son Aengus óg (Macc Oc) were god-kings of the Tuatha Dé Danann, colonists from ‘Greece’ according to the Book of Invasions, who settled Ireland via Iberia early in prehistory after Ireland had become deserted. They fought many battles with earlier colonists. Aengus was the son of Dagda and the river goddess Bóann (after whom the river Boyne takes its name). In essence, the story recounts that Dagda commanded the sun to stand still for nine months, so that the child might be conceived and born within a single day. From this derives his name Aengus óg or ‘Aengus the Young’. As he grew-up, Aengus learned that he would inherit nothing from his real father but he was determined to possess Newgrange. So he sought permission to live in the mound for a day and a night. The following day Aengus declared that a day and a night was equivalent to all days and all nights. By this trick he became the owner of Newgrange.


The building of nearby Dowth is attributed to another king of Ireland named Bressal. There came a great disease or ‘murrain’, which killed both men and animals, leaving only seven cows and a bull. Bressal attributed the plague to the will of the gods and gathered the people together at Bruig Na Boínde (Newgrange). He set them a task to build a great tower in a single day, so that he might reach the heavens and end the plague. The men agreed to work for a day, but this was a trick. Bressal's sister was a powerful druidess and she cast a spell to hold the sun high in the sky creating an endless day for them to build the mound. The spell was broken only because the king committed incest with his sister. Day became night and the men refused to work any more. They returned home leaving behind Dowth: the place of Darkness. ‘Dubad [darkness] shall be the name of this place for ever’, declared the druidess.


I am unsure whom I quote, but it is certainly a truism that archaeologists and other academics will cite myths and legends whenever they support their conclusions; yet will dismiss or ignore them as just ‘myths’ when they do not. So we may wonder whether many of the other legends surrounding Newgrange might have some validity that could be verified by science – especially those that describe the strange astronomy.


The era when the Boyne valley monuments were built is now firmly established by radiocarbon dates since the excavations of the 1970’s. Although usually termed ‘passage graves’ it cannot be proven that they were constructed solely as tombs. The Newgrange excavations, which resulted in the reconstructed monument, revealed a precise alignment of the main passage and ‘roof-box’ towards the midwinter solstice sunrise. Organic material between the stones gave a date of 3150±100 BC. [4] According to the authors of the 2020 DNA analysis this coincided with the era when Ireland was rapidly colonised, displacing an earlier native population.


The primary source for the legends surrounding the building of Newgrange and the other Boyne Valley monuments are the Metrical Dindshenchas, from the twelfth century Book of Leinster. The Dindshenchas, served as a memory aid for the bards to recall the facts of more detailed stories; these were then learned as poetry and recited orally. We may suppose that many more details of the ancient stories have been lost.


The episode is described in the Dindshencha of Boand II, verses 8-9 as here translated by Edward Gwynn. [5]

Thither came by chance the Dagda
into the house of famous Elcmaire:
he fell to importuning the woman:
he brought her to the birth in a single day.

It was then they made the sun stand still
to the end of nine months — strange the tale —
warming the noble fine grass
in the roof of the perfect firmament.

We must trust to the skill of the translator and of the bards who preserved these stories over the millennia. The other report in Dubad, describing the building of the Dowth mound, is rather less precise; recalling simply, an endless day.


His sister came to him, and told him that she would stay the sun's course in the vault of heaven, so that they might have an endless day to accomplish their task. The maiden went apart to work her magic. Bressal followed her and had union with her: so that place is called Ferta Cuile from the incest that was committed there…


Tales of gods and spells may serve to satisfy the general population as to the motives of their rulers. However we may see here a degraded memory of the construction of the passage graves by astronomer-priests who clearly understood real astronomy. In the surviving versions of the Dindshenchas we also detect Christian influence; the building of a mound to reach the heavens is likened to Nimrud and the Biblical Tower of Babel.  Clearly, the later Irish bards who recorded the poems for us had no idea what their ancestors might be describing.


Another Irish story from the Yellow Book of Lecan is The Wooing of Etain, which also takes place in the time of the Tuatha Dé Danann, a generation after the building of Newgrange. It elaborates on many of the themes found in the Dindshenchas. [6] Here again we are told of the Dagda:


…for he it was who performed miracles and saw to the weather and the harvest, and that is why he was called the Good God.


Of the Dagda’s relationship with Bóann, the wife of Elcmar we are told:


The Dagdae charged Elcmar with great commissions, so that nine months passed like a single day, for Elcmar had said he would return before nightfall. The Dagdae slept with Elcmar’s wife, then, and she bore him a son who was named Oengus…


Dagda took his son to be fostered in the house of Mider at Brí Leíth, west of Newgrange; Mider descended from the earlier invaders of Ireland, the Fir Bolg. So Aengus grew-up believing Mider to be his father, but when he was old enough Mider told him of his true parentage. Aengus asked Mider to take him to Dagda, to be acknowledged as his son and to grant him the land that was his due. Dagda was willing, but said he could not grant Bruig Na Boínde to Aengus, as it belonged to Elcmar and he did not wish to anger him further. Dagda himself then suggested a ruse: that Aengus should occupy the mound for a day and a night and lay claim to it. So Aengus threatened Elcmar with his life but spared him on condition that he could occupy the mound overnight, to which Elcmar agrees; but Aengus is not to release it to Elcmar unless the matter is first put to the judgement of the Dagda. Aengus argued that Newgrange was his by right in return for having kept his promise to spare Elcmar; ownership for a day and a night was to mean all days and all nights. The Dagda so gave his judgement and placated Elcmar with a grant of good land elsewhere.


The story continues a year later when Mider comes to visit his foster-son. He asks Macc Oc for a reward of the fairest woman in Ireland, Etain daughter of Ailill. However, Ailill will not give the girl to Mider and demands a price of gold and silver from Macc Oc. He also insists that he ask the all-powerful Dagda to clear twelve plains on his land in a single night. Thus, the myth explains how the twelve great rivers of Ireland were set to flow towards the sea, where no rivers had flowed before!


Ailill releases Etain to Mider and he returns with her to Brí Leíth, but there is an obstacle. Mider has a first wife, Fúamnach, a powerful druidess; in her jealousy she turns the beautiful Etain into a scarlet fly that follows Mider wherever he goes. The complex story may be summarised in its most important elements. Fúamnach summons up seven years of lashing winds that blow the fly away, but at the end of that period the fly returns and settles on the tunic of Macc Oc at Newgrange. The angry Fúamnach summons seven more years of lashing winds to blow the fly away, this time for ever. Why is the precise period of seven years so important to be stated?


The spirit of Etain is later reborn as the daughter of a warrior named Etar and we are told:


Etain was conceived in the woman’s womb and was born as her daughter. One thousand and twelve years from her first begetting by Ailill until her last by Etar.


We see again, the recording of precise numbers in a myth where no such precision is required for a fictional tale. The number is woven into the myth to preserve its era for future generations and gives us a clue that the poem was composed a thousand years after the time of Newgrange, when the astronomy upon which the original narrative was based had already become arcane.


The second half of the Etain story need not greatly concern us; it describes how she is reborn as a young girl and how Etar is tempted by an otherworldly visitor, to visit Mag Már, ‘the great plain’: one of the many names of the Celtic Otherworld. Thus we see a typical theme found in many Welsh and Irish myths, where a well known hero-figure is woven into a semi-fictional tale to preserve the knowledge of the Land of the Dead.


If this strange astronomy were found only in the Irish legends then it might be easier to dismiss them as just ‘myths’ – but this is not the case; there are parallel supporting references from other cultures.


In Search of Thule

The Roman writer Pliny describes the phenomenon of the Arctic winter and he leaves us a further clue: that the phenomenon of the midnight sun could sometimes occur in the island of Mona (Anglesey); an island that was sacred to the British Druids. [7] Anglesey lies on a similar latitude to the Boyne, just across the Irish Sea. The ultimate source for this belief could only have been the Druids of Anglesey themselves. Pliny continues that the same phenomenon also occurred in the remote northern Island of Thule. [8]


In his description of Britain, Pliny describes the location of Thule, saying that the crossing to the island began from the largest of the outlying British islands, called Berrice:


The most remote of all those recorded is Thule, in which as we have pointed out there are no nights at midsummer when the sun is passing through the sign of the crab, and on the other hand no days at midwinter. Indeed some writers think this is the case for periods of six months at a time without a break. [9]


Notwithstanding the opinion of Gerald of Wales in his History and Topography of Ireland that Thule was an island well known in the East, but completely unknown in the West, it is clear that classical geographers from the Mediterranean did not know where Thule actually was. [10] The remark of Pliny above would suggest that it was Iceland, but other geography derived from the voyage of Pytheas would seem to be describing the Outer Hebrides. [11]


By the time that Procopius wrote in the sixth century AD the north was better known. His references to Thule are clearly describing Scandinavia, the northerly extent of which remained unknown. [12] He tells us of the Scrithiphini or ‘skiing Finns’: the Saami people who lived there. In his account he describes the forty days of darkness around midwinter and their fears that the sun might never return:


And when a time amounting to thirty-five days has passed in this long night, certain men are sent to the summits of the mountains – for this is the custom among them – and when they are able from that point barely to see the sun, they bring back word to the people below that within five days the sun will shine upon them.


Unlike the Irish, the northern Saami would have regularly experienced the summer midnight sun and would be unconcerned by it. However, they also experienced the cold winter months of darkness. Why would they be so worried that, in some years, the sun might not return? As the polar seasons are today a regular and predictable calendar phenomenon, we may ask why the Scrithiphini should fear that the sun might not behave as expected. This may be a folk-memory of the same abnormal seasonal phenomenon that is described in the Irish myths of Dubad.


The proto-Finns lived to the south of the Saami; and in the earliest known times were spread across an area around the Gulf of Finland, where today we find northern Russia and the Baltic states. In their Kalevala songs, they too preserved an oral tradition about the disappearance of the sun. In Runo XLVII we find the myth of the theft of the sun and moon. The shaman Louhi seeks revenge on the people of Kalevala and sends disease to kill the people and their cattle. She hides away the sun and moon. The good shaman Väinämöinen heals the sick and forces the evil Louhi to return the sun and the moon to the sky.


As the ancient homeland of Finns and Estonians lies on the same latitude as Britain and Ireland then they should have experienced the same seasonal abnormalities as are described by the Irish. In any rationalisation for such astronomy, this must imply a temporary dip of the zodiac below the horizon, such as occurs in an Arctic winter. Unfortunately the Kalevala myths are quite timeless.


Norse mythology has the myth of Ragnarok; the Fimbulvetr is a prophecy of a harsh winter that will last for three years without a summer in-between as the wolf Skoll swallows the sun. Ragnarok will bring with it many other upheavals and human struggles. Again the myths are timeless, but we may assume that the ancestors of the northern Germanic peoples lived in southern Scandinavia and the Baltic coasts; and their expansion north is recorded in historical times.

From as far away as China we find the myth of Kung Kung (Gong Gong) in the time of the legendary empress Nu Wa (Nüwa) in whose reign a cosmic event is recorded. There are many variants of this story.


We are told of a battle between Gong Gong and Zhuan Xu for the imperial throne, which became so violent that the sky tilted-over! Gong Gong collided with one of the pillars of heaven about which the sky rotates. The balance of the world was restored only when empress Nüwa repaired the heavenly pillar, but her patch was imperfect! We are told that the world became tilted towards the southeast while the sun and moon shifted to the northwest; and this supposedly explains why all the rivers of China flow towards the east. Subsequently we hear many legends of how the earliest emperors struggled to control the floods of China’s great rivers.


The era of Nüwa is only loosely defined by the Chinese legendary chronology, but some time before 2850 BC gives us an indicator for when these cosmic events supposedly occurred.


The seven year rhythms in the climate and its use as a unit of time – as found in the Etain story – are widespread in Welsh and Irish myths. Seven-year rhythms from other parts of the world are most widely understood from the Biblical story of Joseph, with its seven good years followed by seven lean years. Whether the Joseph story recalls real events or whether it be an apocryphal tale to warn future generations what to do, should it ever happen again, is worthy of debate.


The seven year climate rhythm is also found in the Babylonian Flood story in the Epic of Gilgamesh, which also dates from the third millennium BC. [13] The god Anu gives a prophecy of a famine so deep that the dead will outnumber the living. He says to Ishtar:


If I do what you desire there will be seven years of drought throughout Uruk when corn will be seedless husks. Have you saved grain enough for the people and grass for the cattle…


An Egyptian record of a seven year famine is also preserved on the Famine Stela at Sehel Island in the River Nile, which tells of a food scarcity in the reign of King Djoser. Egyptologists now prefer to recognise the Biblical story as one among many memories of seven-year famines throughout near-eastern culture. Again, the dating of Djoser is early third Millennium BC, around 2750 BC.


Whenever we encounter memories of similar phenomena among geographically dispersed ancient peoples then we should ask how this can be so? It cannot just be dismissed as ‘myth’ as that would require diverse ancient peoples to come together to standardise their beliefs just to confuse later generations! Why would they choose a seven-year rhythm that just happens to conform to the known characteristics of the Earth’s rotational wobble? Why not choose five or ten years? Why not just say ‘many years’? Such explicit numbers are always an indicator that a memory of something real has survived as a fossil within the oral myths.


We may also recall the Biblical references in the Book of Joshua to the sun ‘standing still’ in the sky; [14] a story which would have been well known to the later Christian bards who recorded the Irish legends. They would surely have recognised the old stories as confirmation of their Christian teachings – otherwise the myths would have been suppressed like so many other pagan beliefs.


This theme of the rotation standing still was echoed in the amusing 1930’s Alexander Korda film of H.G. Wells’: ‘The Man Who Could Work Miracles’. The hero, George Fotheringay is granted god-like powers. [15] In his folly, he orders the world to stop spinning and unleashes chaos – at which point God puts an end to the experiment and restores the normal rotation. Common sense should tell us that this is not a valid mechanism for a physicist to consider. Notwithstanding the vast energy that would be required to halt the diurnal rotation without demolishing the planet, what force is there to then set it spinning again without similar chaos? Think again.


A more plausible mechanism to explain the ancient astronomy would be a ‘nodding’ of the axis that could temporarily bring polar conditions further south. In the Irish myths, the sun appeared to remain high in the sky (i.e. it did not set); as clear a description of a long arctic summer day as we could wish, but it is somehow extended to the nine months so that Mac Oc could be conceived and born within a single day. How seriously should we take the precise statement that it lasted for nine months?


In my own earlier research for Atlantis of the West I remarked on the probable early dating of the Irish legendary-history, which went against the then-prevailing scholarly consensus. This held that the legends in the Irish Book of Invasions were mere literary fictions, supposedly created no earlier than the arrival of Irish-speaking Celts during the Iron Age. If I may quote my own earlier words:


…the story of Etain is set unequivocally within the era of the Tuatha De Danann…this fits quite well within the chronology previously established, from the Book of Invasions, suggesting a date of about 2800 BC for their arrival in Ireland. It is almost as if the references to the strong winds were deliberately woven into the story in order to preserve its era. [16]


However, with the benefit of the archaeological dating it might now be better to condense the era of all the Irish invaders described in the Book of Invasions to the few decades around the building of the passage graves, perhaps as early as 3150 BC and contemporary with the First Dynasty of Egypt. Now that DNA evidence has discredited the older dogma about Iron Age Celts it is easier to see that the insular Irish Celtic language and culture arrived much earlier, perhaps during the early third millennium BC – and that the oral legends were recorded by the bards in an early form of Gaelic – rather than translated from some unknown ‘pre-Celtic’ language.


The concept of the long polar day and night was certainly understood by the geographers of Greece and Rome; and we may presume that they gained their knowledge from first-hand experience by natives of more northerly lands. The obvious suspect here is the lost astronomy of the Druids. [17] Pliny describes the long polar days and nights much as we recognise them today, but no-one at that era could have actually experienced conditions at the North Pole.


At the North Pole six months of continuous daylight occur; reducing such that at latitude 66.5⁰N, at the Arctic Circle, the sun just skirts the horizon on the day of the solstice. Just south of the Arctic Circle is a region of about six degrees in which Civil Twilight occurs as the sun dips just below the horizon; plus a further six degrees of Nautical Twilight. If such were to be observed as far south as Anglesey or the Boyne valley then it might have been considered as daylight. To find such conditions today one would need to experience the ‘white nights’ of St Petersburg, or anywhere along a roughly 60⁰N latitude – Helsinki, Stockholm, Bergen or Shetland. This phenomenon occurs only on the days around midsummer solstice.


Of course in the southern hemisphere the opposite phenomenon of an Antarctic winter would simultaneously be occurring. However, as there was no human presence in those regions until more recent millennia then it would have been witnessed only by penguins! Logically an extended polar night should also have been experienced in the northern hemisphere, either before or after the ‘endless-day’. We are not told that Dubad was anything other than the return of normal days and nights, but the other northern myths described above would seem to describe a polar night.


Consider how this could happen. We may immediately rule-out here a true change of obliquity, that is, a change to the tilt of the Earth’s principal axis in space. Notwithstanding the prohibitive energy requirement, an increased obliquity such as would drag the Arctic Circle further south would only result in a six-month polar day being experienced further south – not a nine-month day as is described. For the ancient observer to experience a day that lasted nine-months then it would imply that the axis was somehow precessing around the orbit, prolonging the solstice conditions.


The Free Nutations of the Earth

The Earth has two modes of free wobble should the rotational axis become disturbed. The better known is the Chandler wobble, a body-wobble routinely measured by modern geophysicists. This could be excited by internal rebalancing within the Earth. It would be accompanied by sea-level variations, floods and changes to the geodesy of the land. However, it does not seem to be a good model for the events described in the Irish legends – although we do find these phenomena described in other myths, such as the Chinese stories related above.


A better candidate for the Newgrange myths would be the Free Core Nutation (FCN); a second theoretical oscillation known to geophysicists but which is vanishingly small on the Earth today. It could only occur should the axis of the outer crust and mantle become displaced from that of the fluid core, but would require an initial external force to excite the motion.


The core nutation is a motion of the instantaneous axis of rotation in space, which would be accompanied by only a small body wobble. Thus it would be experienced by humans as an irregular motion of the sky; just as we perceive the daily rotation of the Earth as if the sky were rotating rather than the planet upon which we stand. The theoretical period of the core nutation has now been estimated from the various models and equations at 432 days; [18] and once triggered it should persist for thousands of years. As a free transient motion, its amplitude must decay exponentially to rest, being damped by the fluid friction at the core-mantle boundary. On the Earth today the internal and external axes are almost perfectly aligned and the motion is extinct, leaving us with only equations and theory.


To an observer on the surface during such an episode, the sky would appear to be rotating daily about a point, an excitation pole, which would itself be describing an irregular circuit about the true pole of the sky. This is our modern celestial pole – or such as we could project it back allowing for secular variations. The celestial pole is determined in the instant of the event that disturbed the axis. The excitation pole would be describing a (retrograde) circuit around the celestial pole sometimes enhancing and at other times suppressing the seasons over a cycle of roughly seven-years; gradually spiralling inward as the oscillation is damped. Since the rate of decay is exponential then its amplitude would have reduced most rapidly in the early decades after the disturbance.


It is important to distinguish between the motion of an excitation axis and that of the principal axis. The principal axis could only be changed by an external force from space, but we need not debate here what this force was; the geophysicists will speak vaguely about ‘sources of excitation’ within their theoretical models. The development since the nineteenth century of the Kelvin-Hough model of the Earth as an elastic shell containing fluid resulted in a better understanding of the theoretical oscillations. The second mode of wobble would require the axis of the shell to be tilted one way, with a compensatory displacement of the fluid core in the opposite sense; the axes of the two layers would then precess about the principal axis in a conical motion, interacting at the core-mantle boundary.


Geophysicists can only study the tiny oscillations of the Earth today. The Chandler wobble is measured only in arc-seconds; the core nutation so small as to be barely detectable! The modern amplitude is only of the order of 20-30cm. The same equations would apply to a much larger motion; however we cannot be certain that the same constants of elasticity and fluidity would apply in extreme circumstances. There is every reason to believe that a significant displacement of the axis of the outer shell might become chaotic in nature – completely unpredictable. The events that we see described in the Celtic myths would demand an erratic nodding motion of at least 6-8⁰ of latitude, in order for polar twilight conditions to occur as far south as Ireland. Some may find this hard to accept.


However, before you are tempted to raise the speculation flag and declare all the above to be pseudo-science, think again. No it isn’t! The conditions that must prevail under the regime of a core nutation were first derived by William Hopkins as early as 1839 which later models of the Earth as an elastic shell surrounding a fluid core all cite; if I may quote him here.


Since  the  motion  of  the  interior  fluid  cannot  be  subjected  to  observation,  it would be  useless to  make  the substitution of  numerical values  in  equations.  We may remark,  however, that the motion  of the axis of  instantaneous  rotation of the fluid will be exactly similar to  that of the axis  of  the shell, and of the same order, as is easily seen  by comparing  the two equations  just  mentioned.

…By this inequality, therefore, alone the  points  P and  P' would  describe circles about  the  same  centre in  the  same periodic time, with  radii in the ratio of  ⅟1: ⅟2 and differing in angular position by 180⁰. The motion now described is that which would obtain if no extraneous disturbing forces acted on the spheroid, and the axes of instantaneous rotation of the shell and fluid should be separated by a small angle.  It is a case of rotatory motion which has not before been investigated.

…In addition to the above motions of precession and nutation, the pole of the earth would have a small circular motion… [19]


Later researchers would censure Hopkins for flawed mathematics and geology, but then negative criticism is what academics do best. Hopkins is a forgotten pioneer. His overall conclusions about the nature of the free core nutation were largely correct. However, he believed that his investigations showed the interior could not be fluid, because it was not observed to actually behave that way. Geophysicists neglected the existence of the core nutation for 130 years until the second half of the twentieth century. When in the 1980s I began to consider its relevance in ancient astronomy and myths, it still didn’t have a recognized name.


Conical Chaos!

The attitude of the principal axis in space need have been displaced only a little by the initial excitation. The misaligned axes of core and mantle would then be linked by fluid viscosity at the core-mantle boundary. Geologists have only recently discovered continent-sized regions at the base of the mantle, linked to volcanic hotspots, along which magma could flow freely. [20] However, although the derived constants and equations may hold for the small-amplitude oscillations measurable today, it is possible that for a larger displacement the spatial coning motion could become chaotic and unpredictable.


The concept of chaotic motion within a system of conical motion goes as far back as the experiments of Robert Hooke, which pre-date Newton’s physics. As discussed in the paper by Argentina et al, Hooke must have observed this chaotic motion in his own experiments to study Kepler’s planetary orbits and so restricted his experiments with conical motion to only small angles. [21] Chaotic rotational motion is observed by astronomers for small non-spherical satellites and comets, such as that of Saturn’s moon Hyperion. An analysis of how chaos theory might apply to the Earth’s wobble must await some practical observations, such that the geophysicists have a real rather than a theoretical oscillation to consider. Otherwise, to quote geophysicist Kurt Lambeck:


…[the] parameters are all poorly known, making any discussions of damping mechanisms, and for that matter of the excitation processes of an as yet largely unobserved oscillation, little more than speculation.  [22]


Since the 1980s when Lambeck wrote this, great strides have been made in the study of the tiny motion of the axis on the Earth today. Latest measurements give a period of 431.4 days. [23] This interval of 432 days and multiples thereof are also found in ancient Indian calendars and Babylonian astronomy; and this hardly seems coincidence. [24] Perhaps the ancient astronomers have left us the real observational data that modern geophysicists need to fully understand the motion.


Not to forget the Swans!

There is one more astronomical clue in the Irish legends and it comes from the various references to swans – yes, swans! Irish mythology is replete with stories about swans; the characters often transform into swans, as in the story of Etain.


In The Children of Lir, the children are changed into swans by a spell that traps them for 900 years – another precise number. By the end of that time the age of the Tuatha Dé Danann had long passed and a Christian priest changes the swans back into children – but they age rapidly and die.


Another myth, The Dream of Aengus again concerns Aengus óg. He dreams of a girl named Caer and falls in love with her; but she and her sisters are transformed into swans every second Samhain (October 31st) and they then remain in the form of swans until the following Samhain. Aengus sets-out to find the swan that is Caer and to undo the spell! So again we see precise numbers in a myth. What might be the significance of this three-year period?


The swans that over-winter in the Boyne valley and in western Scotland are migratory Bewicks swans. Every spring the birds fly to Iceland to experience the polar summer north of the Arctic Circle, where there is a brief period of abundant food for their offspring; but each autumn around mid-October they return. It may be that every three years or so, in the unusual conditions of a nutation, the swans did not experience their usual climate trigger to fly north and believed that they were already in their summer home. Thus their anomalous presence in Ireland over the summer months was remembered in so many myths and legends.


It is easy to see that, for the common people, the swans were seen as somehow bringing with them the abnormal seasonal conditions. This may have been how it was explained to the people by the bards in their songs. As such, the ancient Irish astronomy has come down to us through oral transmission by later generations of bards who could not understand what-on-earth their forebears were talking about!



Firstly, it is necessary to accept that myths are a degraded memory of something real and are not just fiction. So, to attempt a summary of the astronomy that the ancient Irish legends may record, based on the trail of cross-disciplinary clues presented above, would be something like as follows.


Late in the fourth millennium BC an ‘astronomical event’ disturbed the Earth’s rotation. It separated the rotation axes of the crust and mantle from that of the fluid core and it began to wobble. The first mode of wobble would have decayed within around twenty years and relative normality would be restored. This catastrophic phase was completed (but perhaps still within living memory) by the time that the Tuatha Dé Danann colonised a much depleted Ireland.


However, the core nutation would still have been ongoing and causing seasonal climate variations that could not be easily predicted. The Irish and also the Britons set out to understand it by building astronomically aligned monuments to track the sun’s motion in the sky. The oscillation must initially have been chaotic, causing large excursions of the excitation pole and resulting in irregular arctic summers and winters as far south as Ireland. This would demand a core nutation of at least 8⁰ of latitude – although the principal axis (the obliquity) need only have changed by a small angle. This is the era that is recalled in the Dindshenchas and other origin myths about Newgrange.


It seems that within a generation the rate of exponential decay was such that the oscillation had settled into a more stable pattern, as predicted by the geophysical theory; and we see the references to the seven-year rhythms in the climate as the nutation-seasons alternately suppressed and enhanced the annual seasons. Exponential decay is a powerful effect, such that the amplitude of the nutation should have decayed to become barely noticeable to the common people within a few hundred years. However, its effect on the sun, moon and stars would still have been observable by competent astronomers until it was extinguished, some time in the mid first millennium BC.


It is little use to seek hard evidence of a transient wobble that has long since decayed to rest. What should we expect to find? It should have left its mark in the climate and sea level record; and perhaps in tree-rings, ice-cores or in the record of volcanism and earthquakes. All these clues do exist but are attributed to other causes by the various specialists. The era at which to look for evidence is clearly established by the archaeological dating of Newgrange to the period 100 years either side of 3150 BC.


So much then for cross-disciplinary analysis of ancient fossil myths; where else might you find Irish mythology discussed alongside incest, DNA, radiocarbon dates, geophysics and migratory swans? Will any specialist dare to put names to the human remains found in Newgrange and restore, perhaps, a piece of ancient Irish history that is older than the pyramids?


Relevant Hyperlinks




1 Cassidy, L.M., Maoldúin, R.Ó., Kador, T. et al. A dynastic elite in monumental Neolithic society. Nature 582, 384–388 (2020).


2 Haak, Wolfgang (June 11, 2015). "Massive migration from the steppe was a source for Indo-European languages in Europe". Nature. Nature Research. 522 (7555): 207–211. arXiv:1502.02783. Bibcode:2015Natur.522..207H. doi:10.1038/nature14317. PMC 5048219. PMID 25731166.


3 Mittnik, Alisa (January 30, 2018). "The genetic prehistory of the Baltic Sea region". Nature Communications. Nature Research. 16 (1): 442. Bibcode:2018NatCo...9..442M. doi:10.1038/s41467-018-02825-9. PMC 5789860. PMID 29382937.


4 Ray, T. P. (1989) The winter solstice phenomenon at Newgrange, Ireland, accident or design? Nature, 337, 343-5


5 Gwynn, Edward (ed.), "The Metrical Dindshenchas", Royal Irish Academy Todd Lecture Series, Hodges, Figgis, & Co., Dublin ; Williams and Norgate, London; Part 3 (1913)


6 Ibid, part 4 (1924)


7 Pliny, Natural History, II, LXXVII


8 Pliny, Natural History, IV, xvi, 104


9 ibid,


10 Gerald of Wales, History and Topography of Ireland, 50


11 Strabo, IV, 5, 5


12 Procopius, History of the Wars, Book VI, XV, 4


13 The Epic of Gilgamesh, from the translation by N.K. Sanders, Penguin, Harmondsworth, 1972


14 Joshua, 10, 12-14


15 H.G. Wells ‘The Man Who Could Work Miracles’, a short story published in The Illustrated London News; Summer 1898.


16 Dunbavin, Paul (2002) Atlantis of the West, Constable & Robinson, London, ISBN: 1-84119-716-5 (page 235)


17 Caesar, The Gallic War, VI, 14


18 F.  Roosbeek, P. Defraigne, M.  Feissel, V.  Dehant, The  free  core  nutation  period  stays between  431  and  434  sidereal  days, Geophysical Research Letters, vol. 26, no. 1, pages 131-134, January  1, 1999


19 Hopkins, W. (1839) Researches in Physical Geography, Phil. Trans. R. Soc. London, 129, pp 381-423


20 D. Kim, V. Lekić, B. Ménard, D. Baron, M. Taghizadeh-Popp

Sequencing seismograms: A panoptic view of scattering in the core-mantle boundary region

Science 12 Jun 2020: 1223-1228


21 Médéric Argentina, Pierre Coullet, Jean-Marc Gilli, Marc Monticelli and Germain Rousseaux, ‘Chaos in Robert Hooke's Inverted Cone’, Proceedings: Mathematical, Physical and Engineering Sciences Vol. 463, No. 2081 (May 8, 2007), pp. 1259-1269 Published by: Royal Society


22 Lambeck, K. (1988) Geophysical Geodesy – The Slow deformations of the Earth, Clarendon Press, Oxford,


23 Xiaoming Cui , Heping Sun , Jianqiao Xu, Jiangcun Zhou and Xiaodong Chen, Detection of free core nutation resonance variation in Earth tide from global superconducting gravimeter observations,  Earth, Planets and Space (2018) 70:199


24 Dunbavin, Paul (2005) Under Ancient Skies, Third Millennium Publishing, Nottingham, ISBN:0-9525029-2-5 (see chapter 4)

Copyright: Third Millennium Publishing, October 2020 V 1.2

Citation: Dunbavin, Paul, (2020) Irish God Kings and a Nine-month Day, Prehistory Papers, pp 196-216, Third Millennium, ISBN: 978-0-9525029-4-4

Tags: Irish god kings, Dindshenchas, Dagda, Oengus, nine-month day, Newgrange, Dowth, Dubad, core wobble, free core nutation, polar day, polar night