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Neolithic Ireland - Newgrange

Newgrange and the Boyne Valley monuments – advanced lunar calculations and observation of the effects of precession of equinoxes in Neolithic Ireland - Part 2

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There is much about Newgrange that is mysterious. A lot of Ireland’s myths were written down by Christian monks around a millennium ago. Some of these texts record descriptions of Newgrange including: " Mac an Og's brugh brilliant to approach", "yonder brugh chequered with the many lights" and "the white-topped brugh of the Boyne". If the cairn had slipped in the Bronze Age, as the archaeologists tell us, sweeping the white quartz stone that decorated its front out onto the ground, to be covered by the subsiding rocks and pebbles, are such mythical memories as these recollections of Newgrange as it was in the remote past?

The whole valley is dedicated to the goddess Bóann, or Bóinn, which is a name that means ‘white cow’. This white cow goddess gives her name to the river Boyne, which flows around the great peninsula upon which Newgrange, Knowth and Dowth are situated. Of huge significance is the fact that the river would appear to have been considered the earthly reflection of the Milky Way, the bright band of our galaxy which runs through the night sky. The river is Abhann na Bó Finne. The Milky Way is known in Irish as Bealach/Bóthar na Bó Finne, the Way/Road of the White Cow. Newgrange is known in Irish as Brú na Bóinne, the mansion or womb of Bóinn.

But the astronomical implications of Newgrange and its sister sites are much greater than this. There is evidence at Knowth and Dowth of calculations relating to the moon, knowledge of complex lunar movements possibly including the prediction of lunar eclipses. At Knowth, the aptly named ‘Calendar Stone’, one of its many giant kerb stones, contains markings including crescent and full moons in a counting pattern that appears to enumerate a five-year lunar interval, part of what is known as the Metonic Cycle of the moon, which is 19 years long. There are words for this 19-year cycle in the Irish language. It was supposed to have been discovered by a Greek called Meton in the fifth century BC, and yet there are markings on Knowth’s kerbstones that would indicate it was studied and recorded around 2,800 years before Meton ever existed.

The number of kerb stones at the big monuments could be significant too. At Knowth there are 127 kerb stones, which is half the number of sidereal lunar months in a 19-year Metonic Cycle. In other words, if you count each kerb as a sidereal lunar month, and go once around the whole perimeter, and then back again to where you started, you’d have counted a Metonic Cycle.

At Dowth, there are 115 kerb stones. This is half of 230, which is the number of lunar synodic months in a so-called ‘moon swing’ cycle, the time it takes the moon to run through its extreme rising and setting points on the horizon and back again. This cycle is also known as the ‘standstill’ cycle, and is 18.6 years long. Alexander Thom, a Scottish engineer who studied hundreds of Britain’s stone circles and found many of them were aligned on lunar risings and settings, maintained that anyone studying the maximum and minimum declinations of the moon (what he called the lunar ‘standstills’) would be able to predict eclipses.

Remarkably, the legend about Dowth tells about a sudden darkness, as if from a total eclipse, falling upon the men of Erin (Ireland) as they built the cairn so that the king, Bresail Bó-Dibad, could reach heaven. The darkness caused them to abandon their task, and the legend said that the place would ever more be known as Dúbhadh (Dowth), which means ‘darkness’.

Further to the observation and calculation of complex lunar movements, it would appear that the mound builders might have perceived the greatest cosmic cycle of them all – precession of the equinoxes. This slow wobble of the earth’s axis over a period of 25,920 years, causes the sun’s equinox and solstice positions to regress westwards through the zodiac, and another obvious result is that the north pole of the sky slowly points out a great circle over that period. We know Polaris as the North Star today, but back in the late Neolithic, the pole star was Thuban in the constellation Draco.

At Dowth, a series of seven sun carvings resemble the Dogon symbol for a heliacal rising. When Dowth was built, the bull constellation, which we know today as Taurus, would have been rising out of the east, with its small cluster, the Pleiades, or ‘Seven Sisters’, rising due east in the pre-dawn sky of the spring equinox. Is this what the ‘Stone of the Seven Suns’ means? When Richard Moore and I first suggested this on back in the year 2000, we were pleasantly surprised at how many people thought that was a good explanation of the stone’s symbolism. But it was much more interesting than that. When you sit with your back to the stone, you are facing to the east, towards the horizon where the Seven Sisters would be appearing in the pre-dawn sky of the Neolithic Vernal Equinox. Of further fascination is the legend of Dowth, which says that it was built on the command of the king, Bresail Bó-Dibad (lacking in cattle) at the time of a great cattle famine which left saw just one bull and seven cows remaining in Ireland. Is this a reference to the bull and its little cluster of seven stars?

A series of observations of heliacal risings in the east over a period of a few generations would reveal the slow movement of the sun’s position through the zodiac, caused by precession of the equinoxes. And we have reason to believe that the mound builders of the Boyne Valley were very interested in precession and its fascinating effects on the stars.

The alignment of the passage of Newgrange towards Red Mountain, where the solstice sun comes up, continues into the distance towards another small passage-tomb called Fourknocks, which lies 14.7km (9.1 miles) away. The passage of Fourknocks, in turn, points to the place on the horizon where, around 3000BC, the bright star of the swan constellation, Cygnus, would have been rising after a brief ‘scrape’ with the horizon.

So Newgrange points to Fourknocks, and Fourknocks pointed to Cygnus in the Neolithic. Fascinatingly, there are a number of myths about swans at Newgrange, the most famous of which features Oengus Óg, the owner of Newgrange, who dreams of a beautiful woman and wastes away out of love sickness for her. Eventually, with the help of his Tuatha Dé Danann family and friends, his lover is found at a lake called Dragon’s Mouth, in Tipperary, where she has taken the form of a swan. Oengus is told he too must transmogrify into a swan in order for them to become lovers. He takes the form of a swan, and they fly to Brú na Bóinne (Newgrange), where they live happily together.

Newgrange is also an important wintering ground for the Whooper Swans, which come to Ireland every year in large numbers from Iceland. They arrive in October, and return to Iceland in March. Ornithologists have long said that Newgrange is one of the most important wintering grounds in Ireland, because of the fact that it regularly attracts more than fifty birds each winter. Did the ancient mound builders believe that the swans were carrying off the souls of the dead after winter time, towards the north, perhaps towards that region of the sky in which the great cross-shaped swan constellation was situated?

There are more corroborating factors for this thesis. The passage and chamber of Newgrange are cross-shaped, like the constellation itself. The Cygnus star group sits in the bright band of the Milky Way, as if the swan is gracefully gliding along the surface of this stellar river. Oengus’ mother was Bóinn, from whom the river, the Milky Way and indeed the whole valley was named.

What makes the Cygnus alignment very special is its precessional significance. For almost the entire 25,920-year cycle of precession, Cygnus is circumpolar, i.e. its stars do not set below the horizon. But for one short period of time, perhaps around a century, the bright ‘tail’ star, Deneb, appears to glance along the northern horizon and briefly disappear. The time this was happening was the period when Newgrange and Fourknocks were built. It was as if the builders intended to enshrine this special moment in precessional time.

Another precession-related event of the Neolithic which does not happen today involved the bright ‘ring’ of the Milky Way becoming visible along the whole horizon, from north to east to south to west and back to north again. It is a peculiarity of slow precessional vibration that sees the ring of the Milky Way ‘wobble’ through the sky, like a wedding ring spinning on a table before it comes to rest. But when Newgrange was built, there were certain times of the year when this bright band of stars did just that – it came to rest, settling along the whole horizon, enveloping a Boyne Valley observer in a ring of light. It must have been fascinating to be living at a time when such interesting things were happening in the sky. But it doesn’t stop there.

At the time Newgrange was built, another remarkable cosmic event was happening. The brightest star in the night sky, Sirius, the one we call the ‘dog star’, was rising in exactly the same place where winter solstice sun would rise. It’s declination placed it firmly in the sky window framed by the roofbox aperture of Newgrange, viewed from its chamber. On a nightly basis, for maybe two thirds of the year, the dog star would ‘shine’ into the chamber, or at least it would be visible through the entrance by an observer in the chamber. Was it just purely by chance that this was occurring, or was Newgrange designed as a chamber ‘of many lights’, as the mythology might imply? Was it an observation chamber not just for the sun, but for the moon, the Morning Star and perhaps also the Dog Star as well?

We think that a myth about a ringfort on a nearby hill might commemorate this special alignment, this sacred moment in precessional history. The hill lies towards the southwest of Newgrange. On the shortest day of the year, the sun sets over this hill as viewed from the entrance of Newgrange. The name of the hill, fascinatingly, is Réaltoge, meaning ‘star’, or ‘young star’. The folk tale about the Réaltoge hillfort says that there is gold buried under it, guarded by a dog. Is this the golden light of the sun, which set at Réaltoge on winter solstice in the Stone Age, followed by Sirius, the Dog Star, setting at night?

Newgrange might have been designed as a sort of crude precessional monitor of sorts. This is something we suggested in Island of the Setting Sun in 2006. The slow displacement of the Dog Star caused by precession would have been discernible by dedicated observers in the Newgrange chamber over a period of a few decades. Of course, within a couple of centuries of the monument’s completion, the light of the Dog Star would no longer have been visible in its chamber. Engravings on a stone at the rear of Newgrange, kerb 52, which sits along an axis formed by the entrance kerb stone and the passage and chamber, appear to represent the three belt stars of Orion, pointing to Sirius. And Sirius appears to be sitting exactly on a vertical line on the stone, as if it was directly in alignment with the passage and chamber. In addition to all this, we read in the myths that Bóinn, the mother of Oengus and the moon/Milky Way goddess, had a faithful lapdog called Dabilla.

We found that a meaningful interpretation of the true functions of Newgrange, Knowth and Dowth could only come when several aspects and disciplines were studied, including archaeology, astronomy, mythology, spirituality and geodesy, among others. It was only where stars, stones and stories combined that we were able to see a larger picture emerging.

It is a remarkable testament to the builders that their monuments have survived for more than 5,000 years. It is even more remarkable that information about the cosmological significance of these monuments comes to us through the stories associated with them. We have no doubt that some of these stories have come all the way down, through countless generations, from the time that they were built.

Part 1

By Anthony Murphy



Anthony Murphy

Anthony Murphy is a journalist, author, amateur photographer and astronomer, and father of five children from Drogheda in County Louth. He has been writing since an early age, and has studied the astronomy, archaeology and mythology of the... Read More

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