Spirals on the Long Meg Standing Stone – Clues to Ancient Astronomy
The stone circle of Long Meg and her Daughters in Cumbria, northern England, is one of the easiest to reach as it lies not far from the M6 motorway; and it is also one of the most interesting because of the prominent spirals and cup-and-ring marks on the face of the Long Meg standing stone. In the 1990’s I used it as an illustration of how such alignments might be used to track the position of the sun at the horizon in the event that the Earth’s rotation were wobbling slightly, disturbing the seasons and agriculture at northerly latitudes. An article about the astronomical significance of spiral art at other Neolithic sites is available here with links to various surveys and opinions. [Ref: 1]
The Long Meg standing stone showing the western horizon behind (click for links or find them in the list below)
It is generally accepted by archaeologists that the outlying Long Meg standing stone, is aligned on the midwinter sunset as viewed from the centre of the stone circle. Why choose midwinter? Quite simply, if the need is to forecast whether the spring and summer growing season will be blighted by unseasonal weather then you need to know before the season begins. Archaeologists now prefer that the alignments at Stonehenge and many other monuments were also directed towards the midwinter sunset rather than the midsummer sunrise that is ceremonially re-enacted each summer by the modern Druids.
Firstly: an aside by way of illustration. You may perhaps have noticed, as you sat to eat your breakfast one morning, how the rising sun shone directly into your eyes and you perhaps pulled the curtain over a little. Within a few days the sun will have moved round and the alignment is lost – but on the same day precisely a year later the identical annoying phenomenon will recur. You may not have realised it at the time but you were performing Neolithic horizon astronomy. It is actually quite easy to work out the number of days in the solar-year by setting-up a simple alignment like this to a celestial body and then count the days between recurrences; you don’t need a complex Stonehenge-style circle, or a Newgrange passage-mound, in order to devise a calendar. The Babylonians, Indians, Egyptians and Mayans all created complex calendars without such devices. In the 1960’s when Gerald S. Hawkins, Alexander Thom and others first proposed astronomical alignments at Stonehenge and other stone circles, they were initially ridiculed by the archaeologists of the day; as if the ancient Britons and Irish were not equally capable of performing simple naked-eye astronomy.
In my own books Atlantis of the West and Under Ancient Skies I proposed that the Earth’s rotation was disturbed by an astronomical event in the late fourth-millennium BC. This would have triggered a spiralling motion due to a nutation of the Earth’s axis in space. At an aligned monument such as Long Meg this would cause the points of rising and setting, of the sun, stars and planets, to migrate back-and-forth along the horizon over the period of the nutation. Therefore, I would not doubt the fieldwork on the subject of astronomical alignments at Neolithic sites – merely the stimulus that drove the ancient builders.
The free wobble of the Earth is a transient phenomenon; once triggered it decays exponentially to rest. The swinging of a pendulum is another type of transient. Another aside: suppose that I take you into a room with a stationary hanging pendulum then how could I prove to you that it was recently swinging and that the motion has since decayed to rest? How do you prove to me that it did not swing? Perhaps there was an eye-witness who recorded it – but would you believe the witness? Physicists can describe with equations the simple harmonic motion of a pendulum – but in certain circumstances the motion could become chaotic and unpredictable, as occurs with a double pendulum. A similar unpredictability could also apply to the Earth’s rotation.
A pendulum would swing for ever unless the motion is damped. In the case of a pendulum it is air resistance and gravity that provides the damping; in the case of the Earth’s rotation it is the elasticity and fluidity of the interior; properties that geophysicists have to determine from the tiny motions caused by earthquakes. At present the Earth’s rotation is relatively stable and its nutations go unnoticed by us in everyday life. Geophysicists regularly measure the modern polar motion and the minor pole-shifts that have occurred since measurements began in the 1890s. Commonsense and limited imagination will lead us to assume that things have always been as they are now.
Perhaps the only way to prove whether the Earth’s rotation was wobbling more significantly during the third millennium BC when the aligned monuments were built would be if someone or something recorded it. We have no historical texts from this remote era, only legends and the reports of later classical writers; but we do also have the astronomically aligned monuments with drawings of spirals and we also have natural climate records from such things as tree rings and ice cores; and pollen cores from bogs and lakes. Some of the underlying geophysics is explored below for those who wish to pursue the science a little deeper. [See Note 1] You should always read the small print!
The spiral markings on Long Meg are perhaps the most useful of all the examples of spiral-art found on Late Neolithic monuments. The circle has not been reconstructed so we may trust the alignments. On the stone itself we can discern a notch and a line (which appears man-made) from the edge to the spiral; and pointing towards the centre of the ‘cup-and-ring’ marks. Below it we see another notch and line pointing to a fainter example of a spiral with cup-and-rings; however the linking-line could be a natural fissure. Note also the parallel lines above the spirals and the straight line below. Unfortunately we see the monument after nearly five-thousand years of weathering and a modern wall now interferes with our horizon view beyond.
The upper and lower spiral carvings on Long Meg: the incised line seems to be pointing from the notch through the spiral towards the cup-and-rings that may denote the stone circle. The lower spiral and circle are less easy to see but in this instance the ‘line’ may be a natural fissure. There are also two faint concentric rings towards the left edge of the stone.
While we may trust the horizon alignment of the stones and the carving itself, we cannot be sure that the Long Meg stone has not leaned slightly over the years. By retro-calculation we can determine that the winter solstice sun around 3000 BC should have set at an inclination of around 22⁰ to the horizon behind the stone. There is no point trying to be absolutely precise about retro-calculation as there are so many potential unknowns; but even allowing for some lean it seems unlikely that the inclination of the carved line has any astronomical significance. The spiral carving however seems to be telling us to observe the setting sun from the stone circle; as if it were supplying instructions for future generations as to how to use the monument.
As to whether the Long Meg stone has leaned-over since it was set in the ground then one may ask: what was the purpose of the straight lines and the two parallel lines? There is nothing artistic or decorative about them so clearly they had a practical purpose. The angle of the lower-line to horizontal is about 17⁰ which we may compare with the inclination of the ecliptic (see retro-calculation above). If however, the stone were originally set with the lower line horizontal then the straight left edge with its notches would be approximately vertical. The parallel tracks are approximately at right-angles to the extended-line joining the spiral and rings; and the angle between this and the lower line is about 42⁰. Only excavation could determine whether the stone has leaned, or perhaps whether the markings survive from some previous use of the stone. Without such knowledge the various angles do not help us to understand the monument.
The stone circle of Long Meg and her Daughters
(click the picture for access to Google Maps)
Retro-calculation of the midwinter sunset in 3000 BC (Skymap Pro 6)
You may then ask: does any of this actually prove that the Earth’s obliquity was disturbed during the Late Neolithic? No of course it doesn’t. But pose the question the other way round. If the rotation axis were nodding and causing seasonal variations then how could you forecast it, if all you had were the tools available to Stone Age man? Answer: you would need an observatory something like a stone circle or the chamber of a ‘passage grave’.
At northern latitudes the effect of abnormal seasonal variations would be more acute than at Mediterranean latitudes. The location of the Arctic Circle would fluctuate north and south of its modern latitude. It is the same as if you travelled north or south yourself to make the same horizon observations – except that it would be the pole that is moving not you. However this effect should not be overstated; a nutation of say, a degree or two of latitude would have noticeable effects on the climate, but no more than the equivalent of November or January weather conditions occurring in December (alternating suppressed and enhanced seasons). Such fluctuations would be a matter of survival for farmers at northerly latitudes, but in the physical record the evidence could easily be attributed to other factors by modern climate researchers.
Consider the following quotations on the subject of the arctic summer and winter, taken from Pliny’s Natural History and from Julius Caesar’s commentaries.
Pliny Book II LXXV. LXXVII
Thus it comes about that owing to the varied lengthening of daylight…parts of the earth have continuous days for 6 months at a time and continuous nights when the sun has withdrawn in the opposite direction towards winter. Pytheas of Marseilles writes that this occurs in the island of Thule, 6 days voyage N. from Britain and some declare it also to occur in the isle of Anglesey (Mona), which is about 200 miles from the British town of Colchester.
Julius Caesar V 13
Midway across is (Mona) and it is believed that there are also a number of smaller islands, in which according to some writers there is a month of perpetual darkness at the winter solstice. Our enquiries on this were always fruitless…
Other classical writers and sources could be cited, attesting to the competent astronomy of ancient people. Pliny wrote in the first century AD and Caesar was citing authors from the first century BC – before the Romans entirely destroyed the Anglesey Druids. Whatever ancient oral wisdom they preserved from antiquity was subsequently lost. Classical scholarship has always tended to disparage any link between the Druids and the astronomical alignments at Neolithic stone circles. This goes back to outmoded ideas about an invasion of Iron Age Celts from Gaul, who supposedly brought the Druids with them – even though the classical sources clearly tell us that the order originated in Britain. The links between Stonehenge and the Druids, so scholars told us, were all the invention of the eighteenth century antiquarian William Stukeley, citing Aubrey – and we still hear this dogma today, regularly trotted-out by the television academics. It is perfectly plausible that Iron Age druids and bards should have preserved ancient oral wisdom to be recorded in Roman times. So we do have eye-witness testimony recording the observations when the Earth wobbled on its axis. It’s just a matter of whether you believe the witnesses.
As to whether a nutation of the axis could have carried the Arctic Circle quite as far south as Anglesey does seem doubtful. The Arctic Circle today, lies well north of the Shetlands and other references to Thule in Solinus and in Strabo’s geography are clearly describing Lewis. If the Druids taught of an ancient time, when such extreme obliquity of the axis carried the Arctic Circle as far south as Anglesey then it might imply that the motion became chaotic in the immediate aftermath of the disturbance. However, it seems more likely that a lesser wobble of perhaps 1-3 degrees of latitude caused alarm at Orkney and Shetland, where we also find aligned passage graves and spiral motifs. Some archaeologists, following recent excavations, would like to regard Orkney as the Neolithic capital of Britain and that the building of passage graves and stone circles originated in the far north of Britain. [See Note 2]
Therefore it would be valuable if geophysicists would consider the evidence of the Neolithic monuments and the ancient literary and legendary sources; together with the 432 and 60 day cycles found in ancient Indian and Babylonian calendars. Perhaps then they could propose a coherent mathematical model (hopefully explained in simple-English) of how the real Earth would behave in extreme circumstances. Non-geophysicists such as archaeologists and historians could then cite this research and take it forward without being accused of speculation. This is the problem that one has when a transient motion has decayed to rest – how do you prove that it occurred? It is rather like ice on an aircraft’s wings that has melted away before you can determine why it crashed.
Notes and References:
Note 1: The Small Print!
The present understanding of the Earth’s free-wobbles has been hard-won by generations of geophysicists. The equations give two solutions; the first mode is the Chandler Wobble, named for its nineteenth-century discoverer; the second is the core-wobble or free-core nutation (sometimes called the nearly-diurnal wobble). To describe these motions without resort to equations and the specialist jargon is not at all easy. Both wobbles have a body and a space component as I will try to summarise in ‘plain English’ below together with some links for further research.
These ‘free wobbles’ should not be confused with the forced motions due to the constant pull of the Sun, Moon and planets on the equatorial bulge; these cause the phenomenon of the precession of the equinoxes and are an entirely separate consideration. Geophysicists usually refer to movements relative to a frame fixed in space as ‘nutation’ and reserve the term ‘wobble’ for the body-motion relative to a frame that rotates with the Earth. However usage of the terminology has been somewhat flexible in the past!
To recap the history of understanding, geophysicists first modelled the rotating Earth as a solid ellipsoid. This gives a period of 305 days for a ‘solid’ Earth as calculated by Euler. However when the true polar motion was first detected by Chandler the period was measured at 428-437 days (modern opinions vary). This was modelled by considering the Earth as an elastic shell containing fluid and by adding terms to Euler’s equation for the elastic yielding of the shell and the fluid vorticity. Most models use variants of the Liouville Equation for which a good explanation may be found in references 2 & 4 below. No external force is required to act on the Earth; the modern Chandler Wobble is excited by Earthquakes and deeper internal movements that slightly change the shape and balance of the planet. Using these as tools to probe the interior suggests that the time taken for the motion to decay exponentially to rest is around 68 years, but becoming insignificant after 20 years or so; this should be completely independent of its initial amplitude.
The free core nutation (FCN)) is more enigmatic. Geophysicists still argue about whether it has actually been observed; although it was known as a second solution to the equations since Hopkins in 1839 and can only occur if the axes of the outer shell (the crust and mantle) Lm and the fluid core Lf became misaligned. It should have a period of around 432 days according to IERS.  The second solution languished as a theoretical curiosity until the late twentieth century when some geophysicists claimed to have observed the nearly-diurnal wobble (NDFW). These are in fact two views of the same motion and the name led to much confusion. In my own earlier cross-disciplinary studies (in the absence of a then-recognised name) I referred to the spiral motion of the misaligned axes of core and mantle as ‘core-mantle precession’. The nutation and wobble should be visualised as occurring on top of this misalignment. On the Earth today, the FCN and NDFW are vanishingly small because the axes are aligned.
These various motions are not easy to visualise intuitively. The kinematic diagrams of Louis Poinsot may assist, for which one of the simplest explanations is found here on pages 52-58, in a paper originally intended for astronauts training.  It shows the conical representation describing the body and spatial components of the Earth’s nutations. The point of the cones is at the centre of the Earth and the circles show the relative motion of the axis in space and within the body. Poinsot termed the path of the pole on the Earth’s surface as the polhode; that of the pole in space as the herpolhode. The combined motion of the axis is represented by the line of contact of the two cones.
Poinsot diagrams for the Chandler wobble (left) and for the core or nearly-diurnal wobble.
A useful illustration of the modern Chandler Wobble and its resultant pole shifts is provided by IERS here. It may be seen that the rotation pole (the polhody) makes approximately six circuits of the celestial pole over a seven year period. This happens each time that the tiny modern motion is excited. It is important to note that the spiral motion illustrated is the polhody (the body wobble). For the modern Chandler Wobble the herpolhody (the motion of the axis in space) is so tiny on this scale that it would just be a dot in the centre of the diagram. However, for the core wobble it is the opposite. The Poinsot kinematics shows the much smaller body-cone rolling retrograde on the larger retrograde space-cone. The best estimates (guesses?) of the geophysicists as to how long the hypothetical motion would take to decay to rest suggest that it would persist much longer than the Chandler wobble; perhaps as much as 2500 years. The IERS suggested period of 432 days (other estimates say around 444 days) represents the theoretical 460 day period as clarified by Toomre, modified by the real characteristics of the Earth’s interior. [See Note 3]
As Toomre cautiously put it in his landmark 1974 paper “no process confined exclusively to either the core or the mantle can in principle bring about the misalignment of the angular momenta Lf and Lm that we have seen to be essential to this particular mode…Needed instead are random torques between the two major parts of the Earth”.  This guarded phrasing implies an external force; something hitting or acting on the Earth from space, such as an energetic impact event. Geophysicists at that era could not openly discuss such topics, as to do so would have invited professional ridicule; hence in their research papers they speak cautiously about ‘sources of excitation’ and ‘excitation functions’ taking-place on purely theoretical Earth-models. It is not supposed to actually happen!
Therefore in order to consider a change of obliquity in ancient times (or an ‘axis-tilt’ in common parlance) then it implies an energetic impact event on the surface, or perhaps some other unknown force from outer space that could shake the core. It must excite both modes of wobble and for a time they would interfere, causing as Alar Toomre cautiously put it, the core motion to: “…modify the basic rigid-body mode, the Chandler wobble, by perhaps one part in ten”. But after the Chandler wobble had decayed to rest, the core wobble would persist for many generations, thereby affecting seasonal weather patterns. The interference of the Chandler wobble during the first twenty years or so is again a separate consideration; it would not be a pleasant time to be on the Earth!
Implicit in all this guarded phraseology is that the so-called ‘random torques’, these being external forces, must change the angular momentum and obliquity and, since the shape of the planet is thus modified, it would also cause a pole-shift. While the core wobble is in progress nothing prevents the Chandler wobble from being excited again by purely internal changes to the figure of the Earth until full stability is restored.
Therefore should any non-geophysicist wish to propose a theory of pole-shifts or axis-tilts in the ancient past without having it dismissed by sceptics as Velikovsky pseudo-science; or linked with Dodwell’s ‘proof of the bible’, or Hapgood’s sliding-crust nonsense, then they must grapple with this geophysical terminology and the equations in the specialist papers. Similarly, the geophysicists are neglecting valuable data about the Earth’s interior if they fail to consider the ancient astronomy.
The suggestion that Orkney was the ‘Neolithic capital’ of Britain was made in a BBC television program about the Ness of Brodgar excavations. As so often when a new theory about prehistory is suggested, the establishment archaeologists pounced on it. I hope my discussion above will perhaps offer some motivation behind the building of aligned monuments in the North, but of course it too will be immediately dismissed as is the academic norm with such things. Follow the links below and form your own opinion:
The links here to the website of IERS (International Earth Rotation Reference Systems Service) will give access to further geophysical research on the nature of the Earth’s core. There is now a special department researching the core: The Special Bureau for the Core (SBC). Still largely unknown is the contribution of the solid nickel-iron inner-core; and the extent to which it would further modify any significant wobble and its effect at the surface. See Reference  below.
This article is written for the benefit of the general reader and is not intended to be an academic paper. The following references and the links above will lead to a comprehensive bibliography of relevant research.
2) Ferrándiz, José & Navarro, Juan & Escapa, Alberto & Getino, Juan. (2014). Earth’s Rotation: A Challenging Problem in Mathematics and Physics. Pure and Applied Geophysics. 172. 57-74. 10.1007/s00024-014-0879-7.
4) Leick, Alfred (1978) The Observability of the Celestial Pole and its Nutations; Prepared for National Aeronautics and Space Administration, Goddard Space Flight Center, NSG 5265 jZ6 5; OSURF Project 711055, Reports of the Department of Geodetic Science, No. 262
5) Toomre, A. (1974) On the nearly diurnal wobble of the earth. Geophysical Journal of the Royal Astronomical Society, 38(2):335–348, 1974. ISSN 1365-246X. doi: 10.1111/j.1365-246X.tb04126.x.
Some of the embedded hyperlinks above may not work in the pdf version so access them directly here:
Long Meg Stone Circle
A 2012 survey report on the Long Meg stone circle by Durham University downloads directly here.
Simple Harmonic Motion
Free core nutation and the nearly-diurnal wobble
Polhode and Herpalhode
Copyright: Paul Dunbavin for Third Millennium Publishing, December 2019