after 6,000 years ago, there arose a remarkable community of people
on this island. As if from nowhere, these astute, organised, intelligent
and capable people claimed their stake on this country and began
constructing permanent, indelible monuments which were to stand
the test of aeons of time. They were the megalithic builders.
constructions are Ireland's best known, most explored, and possibly
least understood, monuments. The most famous of these, Newgrange,
is a magnet for tourists, who flock to the Boyne Valley every
year in huge numbers. In 1999, there were 297,000 visitors to
Newgrange, and numbers have been rising steadily. The nearby megalithic
passage mound at Knowth
has recently opened to tourists also, and the third major Brugh
na Boinne site, Dowth,
is also open to the public. So what is it that attracts people
to these sites? What do they come to see? What are they told about
these remarkable monuments?
to the casual visitor, it is clear that there is something distinctly
mystical about Newgrange, Knowth and Dowth. The stark symbolism
etched deeply into the huge megaliths is a written record which
comes to us across over five millennia. At Newgrange, the huge stone
outside the passage entrance is highly decorated with huge, swirling
spirals. At Knowth, nearly every stone is decorated, and the site
has been hailed as having the largest collection of megalithic art
in all of Europe - in fact, over a quarter of all known megalithic
art in western Europe is at Knowth and its satellite mounds. Two
miles to the east at Dowth, there are more decorated stones. At
Loughcrew, 40 kilometres west of Brugh na Boinne in County Meath,
there are the ancient cairns of Sliabh na Caillighe, the mountain
of the witch, again featuring vast amounts of ancient carvings.
Among the familiar
patterns, such as zig-zags, waved lines, spirals and lozenes, there
are some decorations which are distinctly astronomical in nature.
At Dowth, there are stars and sunwheels, at Newgrange there's carvings
that look like a representation of Orion's Belt, at Knowth there
is a wealth of astronomical imagery - crescents and moon shapes,
stars, circles, spirals, sundials and astral imagery, and possibly
even a map of the moon. At Loughcrew there are suns and sunwheels,
stars and much more. Could it be that these sites share a common
astronomical purpose? Are we looking back through the murky mists
of time to an enlightened epoch, a time when men and women of great
intellect and ability mastered their study of the heavens and recorded
what they saw for posterity?
There is a dim light which shines from the remote distance of the
Neolithic past. It carries a message of wisdom, of understanding,
of cosmic awe and inspiration, and astronomical mastery of the highest
We have regrettably
looked upon the ancient people of this land as being primitive,
and in some quarters we are told that these awesome constructs with
their dazzling size and arcane symbols, are merely tombs, used to
bury the dead. Even today, archaeology calls Newgrange, Knowth and
Dowth "passage-tombs". I would like to see that title
removed, and to install a more accurate and fitting description
- something like "astronomical timepieces" or "Stone
Pick up almost
any amateur astronomy book at your local bookstore (or Astronomy
Ireland shop - phone 01-8470777!) and in the history of astronomy
section you will invariably read that the first astronomers were
the ancient Babylonians, or the Chinese. You will also read about
how the Greeks helped to enlighten the world with their many scientific
and astronomical discoveries. Some of these books are progressive
enough to mention that there were ancient astronomers at Stonehenge,
but most overlook Newgrange and Ireland, which is evidently the
place where competent astronomical study actually began.
NEWGRANGE / SÍ AN BRU
Winter Solstice sunrise event at Newgrange, where the sun shines
into the long passage on the shortest day of the year and illuminates
the central chamber, is the most heralded event in the Irish cultural
calendar, and attracts major media attention every year. Most people
know about it, and many gather at the famous mound every December
to witness the event, even though most of them have to make do with
seeing the event from outside. It is a famous example of ancient
astronomy in action in modern times, and is a fitting beginning
to our exploration of the ancient Irish skywatchers.
dawn on Winter
Solstice every year, just after 9am, the sun begins to rise
across the Boyne Valley from Newgrange over a hill known locally
as Red Mountain. Given the right weather conditions, the event is
spectacular. At four and a half minutes past nine, the light from
the rising sun strikes the front of Newgrange, and enters into the
passage through the roofbox which was specially designed to capture
the rays of the sun.
the following fourteen minutes, the beam of light stretches into
the passage of Newgrange and on into the central chamber, where,
in Neolithic times, it illuminated the rear stone of the central
recess of the chamber. With simple stone technology, these wonderful
people captured a very significant astronomical and calendrical
moment in the most spectacular way.
appears to be split into two beams - a higher beam and a lower beam.
This is in fact true, the lower beam being formed by the doorway
to the passage. It is the light which enters through the roofbox,
however, which reaches the central chamber.
For a very short
time, the beam of sunlight enters the chamber, illuminating the
floor. It is a narrow beam, only 34cm wide at the entrance and narrower
in the chamber. Originally, the beam would have struck the rear
chamber orthostat (C8) and, possibly, would have been reflected
onto another chamber stone, C10, which contains the famous triple
spiral. After just 14 short minutes, the beam disappears from the
floor of the chamber, retreats down the passage and once again the
heart of newgrange returns to darkness.
With this most
famous cosmic moment at the epicentre of our study, we can now expand
on the astronomical theme and demonstrate how Newgrange does not
stand in isolation as an astronomical device, despite what many
people might believe. The Winter Solstice sunrise phenomenon is
not the only function of Newgrange. In the book "Uriel's
Machine", Robert Lomas and Christopher Knight have speculated
that the roofbox and passage of Newgrange may have been used to
track down Venus during specific moments in its eight-year cycle.
Certainly the evidence for study of Venus is abundant in the Boyne
the roofbox of Newgrange, there are a series of eight markings,
which the authors have suggested could represent the eight years
of the Venus cycle. This eight-year cycle of Venus ties in very
closely with the metonic cycle of the moon, and may have been recorded
elsewhere at Brugh na Boinne as we will see later.
But it doesn't
stop there. Many astronomers will know that the moon's path through
the sky, although inclined slightly to the sun's path, will take
it into positions which are shared by the sun at certain times of
the year. The points where the imaginary line of the moon's path
crosses the line of the sun's path are called nodes.
It is when the moon is at a node that it sits on the ecliptic, and
when the nodes are located in Gemini and in the gap between Sagittarius
and Scorpio, then the Moon shares the sun's Summer Solstice and
Winter Solstice positions.
This only occurs
twice during a single rotation of the nodes, which takes 18.6 years.
So every nine years, on just a few occasions, a full moon or waning
gibbous Moon which rises in the Sun's Winter Solstice position can,
technically speaking, shine into Newgrange, or at the very least
line up with the passage and chamber.
On July 5th
2001, a group of amateur researchers (most of whom I know, including
Richard Moore), were given special permission by Duchas to access
the Newgrange chamber to see if they could witness the full moon
from the interior of the chamber. Regrettably, some cloud cover
meant the Moon was obscured for the crucial minutes after it rose,
but the cloud did clear in time to allow the group to see the Moon
from within the passage. Although this observation did not prove
conclusively that the Moon can be seen from the chamber, it goes
without saying that if the Moon's position can coincide with that
of the Winter Solstice sun, then the alignment is true.
There may be
more evidence to support a lunar function at Newgrange. The front
of the mound is decorated with a brilliant façade of milky-white
quartz, and some researchers and archaeologists believe the whole
mound may originally have been covered with this brilliant stone.
Perhaps Newgrange was supposed to be the earthly reflection of the
Speculation aside, it is clear that more research needs to be done
on this aspect of the astronomy of Newgrange. The Irish name for
Newgrange is Brugh na Boinne. The word Boinne, from which the River
Boyne is derived, means "White Cow", and the ancient goddess
Boann may have been associated with the Moon. Indeed, some researchers
have pointed out that the period of gestation of a cow is equivalent
to nine and a half synodic lunar months. The word Brugh is interesting
too. Traditionally it has been interpreted by academics as meaning
"mansion" or "house", but there is a word Brú
which I have found to mean "womb" (MacCionnaith Foclóir,
1938). Could the real meaning of Newgrange be "The womb of
the Moon???" The symbolism and interplay between the various
elements involved leads to further speculation about the whole purpose
of the site. We can imagine a full Moon rising over the hill of
Red Mountain, shining across the valley, over the Boyne River, which
has the same meaning as the Milky Way in the sky, and may in fact
have been seen as its earthly reflection. The Irish for Milky Way
is "Bealach, or bothar, an Bó Finne" - the way
or the road of the white cow. Perhaps the quartz façade on
the front of Newgrange is supposed to be another representation
of the Milky Way.
day we will see spread across the front pages of the world's newspapers
the wonderful image of moonlight flooding into the chamber of Newgrange.
research, as opposed to that of us amateurs, has also revealed interesting
astronomical functions at Newgrange. Archaeoastronomer Frank Prendergast
has produced data which shows that even the large standing stones
in front of the entrance of Newgrange, known as the "Great
Circle", were astronomical and calendrical in function. Although
carbondating has placed the construction of the Great Circle to
about 2000BC, over a thousand years after the construction of Newgrange
itself, Mr. Prendergast shows that the stones functioned properly
at that time. His research demonstrated how the shadow of GC1, the
megalith adjacent to the entrance, would have crossed the lower
part of the three spirals on the west side of K1 at the winter solstice;
that the shadow of GC-1 would have crossed through the centre of
the three spirals at the period when the south declination of the
sun was half its annual maximum; that the shadow of stone GC-2 similarly
crosses the same three spirals at the equinox; that the alignment
of GC5 to GC3 pointed towards sunrise when the north declination
of the sun was at half its annual maximum; it would also have been
possible to observe the summer solstice sunrise by sighting across
the top of GC1 and GC-2.
Our own work
has shown how the astronomers of Newgrange may also have used the
star Deneb, in the swan constellation Cygnus,
to help track down the position of the sun during the night before
Winter Solstice. The mystery is heightened by the attachment of
certain swan myths to Newgrange, such as the famous romance story
of Aonghus and Caer. Aonghus' mother was Boann, the Moon, and his
father, the Dagda, owned Newgrange.
The story tells
how Aonghus fell madly in love with a maiden who visited him while
he slept. She visited him in his dreams for a year, and all this
time he could not touch her because she would disappear. His mother
Bóann searched Ireland for the maiden, but was unable to
find her after a year of searching. Aonghus enlisted the help of
his father, the Daghdha, who in turn sought out Bodhbh, who was
the Tuatha Dé Danann king of Munster. Bodhbh revealed that
the maiden was, and brought Aonghus to meet her at Loch Béal
Dragan (Dragon's Mouth) in Tipperary. Bodhbh explained how Caer
was from Sídh Uamhain, an 'otherworld residence' in Connacht.
revealed to the Daghdha that his daughter went in the forms of a
bird and a girl on alternate years. At the following Samhain (November)
she would be a bird at Loch Béal Dragan, and the Daghdha
instructed Aonghus to go there and call her to him. He did so, and
found her in the shape of a beautiful white swan, in the company
of thrice fifty others. She went to him, and he too became a swan,
and they embraced each other and flew three times around the lake.
They then flew together to Brugh na Bóinne and put the dwellers
of that place to sleep with their beautiful singing. Caer remained
with Aonghus in the Brugh after that.
The story says
they took the form of swans and lived IN the Brugh. Is it purely
coincidence that the swan constellation is cruciform in shape, like
the Newgrange passage?? Maybe, and we have to remember there are
other cruciform passages in ancient megalithic mounds and cairns
in Ireland. But the mystery deepens with the addition of the Fourknocks
a lot of people seem to know this, but if you plot the line of the
direction of Winter Solstice sunrise from Newgrange on a map, this
line intersects the small Megalithic mound of Fourknocks, 15 kilometres
to the southeast.
Sunrise 3150 +/-100 BC = 133°54 +/-4' Range of azimuths calculated
by Tom Ray: 133°49' - 137°29)
So in other
words, Newgrange 'points' to Fourknocks, although Fourknocks is
not visible from Newgrange. Fourknocks, in turn, points to a very
unusual azimuth - around 17 degrees east of north, way beyond the
northernmost range of the rising Sun or Moon. What we need to resolve
is whether the passage of Fourknocks is aligned on a significant
star, or constellation. And, in the epoch when this small mound
was constructed, between 3000 and 2500BC (Gabriel Cooney), the star
Cygnus would be rising at this point.
The second significance
of Deneb relates to its precessional importance. Throughout the
entire 26,000 cycle of precession, Deneb remains mostly a circumpolar
object, never setting below the horizon and being visible to observers
at this latitude every night of the year.
in the epoch 3000 to 2500BC, Deneb is at its lowest point in the
entire precessional cycle. At this time it grazes the horizon, and
just about sets below the horizon at due north briefly during this
time, before rising again to remain visible to those who would wish
to watch the star.
of the Aonghus-Caer romance is interesting. It is the reference
to the "Lake of the Dragon's Mouth", where Aonghus found
Caer. This could be a possible reference to the constellation of
Draco, which is a prominent constellation in the northern hemisphere
of the sky.
is particularly relevant in the Neolithic period, because the main
star of Draco, called Thuban, was the pole star for a few hundred
years around the date 2,800BC. It is also fascinating to our story
in light of the fact that Cygnus the constellation is located very
close to the head of the dragon in the sky.
may also be featured at Newgrange. Kerbstone
52 is one of the finest decorated stones of neolithic origin
in Ireland. Located at the northwestern side of the great kerb,
it is diametrically opposite the entrance stone, Kerb 1, and features
a vertical line down the centre. A line plotted between Kerbstone
1 and Kerbstone 52 points in the direction of Summer Solstice sunset.
thorough interpretation of the stone's designs has yet been made,
but I believe it contains representations of the belt stars of Orion,
and that the large 'star' bored into the vertical line represents
Sirius, the brightest star in the night sky. Sirius shared the same
declination as the Winter Solstice sun around 3,150BC when Newgrange
was built, and it is possible the people who constructed Newgrange
were well aware of this coincidental alignment, and therefore they
may have used the passage of Newgrange to watch the precessional
drift of Sirius over long periods of time, even if it was not constructed
for that purpose.
kerbstone, number 51, may contain representations of the constellation
Cassiopeia with its familiar W shape. This is another constellation
which would skim the horizon in the late Neolithic, and its distinctive
shape would have been readily identifiable, as it is today. We know
from ancient myths that this constellation was identified with a
very important deity by the ancients. Charles Squire, in his 1912
volume "Celtic Myth and Legend" says: "For the children
of Dôn were certainly gods of the sky. Their names are writ
large in heaven. The glittering W which we call "Cassiopeia's
Chair" was to our British ancestors Llys Dôn, or "Dôn's
Court". This same children of Don have been identified with
their Irish counterparts, the children or people of the goddess
Danu, and Danu herself was the Irish Cassiopeia.
This is another
constellation which may have been featured as a target of the Fourknocks
construct, and the familiar zig-zag patterns carved on some of the
lintel stones in Fourknocks may be associated with this constellation.
Author Martin Brennan, whose pioneering work on Neolithic astronomy
and art in Ireland has been widely published, suggested that the
quadrangle shapes on these lintel stones may be connected with the
head of the constellation Draco, which as we have already seen was
the polar constellation in the Neolithic.
Some other alignments
at Newgrange are worthy of mention. Site
A is a sizeable tumulus located southeast of Newgrange. It sits
in direct alignment with the Winter Solstice sunrise as viewed from
Newgrange, but is much lower down than the rising sun. Site
B is one of the smaller satellite mounds near Newgrange, and
is located southeast of the great mound at the edge of the Boyne
river. Observations made by us in June 2000, confirm that the Summer
Solstice sun sets directly at Newgrange when viewed from this mound.
Another satellite mound, the largely destroyed Site
U, sits directly due east of Newgrange, and therefore the two
may be aligned on equinox sunrises and sunsets. Just west of Newgrange
there are two satellite sites called K
+ L, which were excavated during Professor Michael O'Kelly's
major works at Newgrange. Much of the passage and kerb stones of
site K remain, and Martin Brennan has pointed out that the passage
is aligned directly north-south.
DOWTH / DUBHAD
we move further to the east, and possibly further back in time,
to the megalithic cairn at Dowth, located less than a mile away.
Dowth in Irish is Dubad, which means "Darkness" or "Place
of darkness". It is the only one of the three great mounds
of Brugh na Bóinne, the others being Newgrange and Knowth,
which has not been excavated and reconstructed in modern times.
archaeological work was carried out here in the middle of the 19th
century, around the time of the Great Famine. By old-style, I mean
the typical Victorian grave-robbing archaeology where the recovery
of valuable finds and treasure is the main objective, and where
little concern is given to returning archaeological sites to their
original state. It was during this work that much of the top of
the mound was removed, resulting in the huge crater in the mound
which can be seen today. There are two known passages at Dowth,
both on the western side. Only part of the kerb of stones is exposed,
along the east, south and southwest of the mound. Many of the kerbstones
remain buried. But some of those which are exposed are very exciting,
especially kerbstone 51 on the east side, which has been named the
"Stone of the Seven Suns".
what appear to be suns, or stars, with rays coming out from the
centre, and with the whole surrounded by a circle. There are seven
of these suns in total, six of which are contained within circles.
Attempts have been made to explain the meaning of these symbols
- some say they are representations of the sun at different times
of the year, others say they represent celestial bodies such as
comets. One thing seems certain - they represent heavenly bodies
of some form. It really is an impressive stone.
It is to mythology,
and particularly the ancient story about how Dowth was built, which
reveals an ancient astronomical symbolism which may help to explain
something about the meaning of the 'Place of Darkness' and the Seven
Suns stone. The story comes from the Dindshenchas,
a collection of ancient stories about Irish placenames, and concerns
Bresal, who was the ruler of the time.
time there fell a murrain on kine in every place in Ireland, except
for seven cows and a bull that increased strength for every farmer
in his time. By him is built the solid hill in the likeness of Nimrod's
tower, so that from it he might pass to heaven, - that is the cause
why it was undertaken". The story continues to tell how Bresal's
sister stopped the Sun from moving so that there would be 'no night
but bright day' until work reached completion. Unfortunately, they
committed incest and the Sun went down . . .
The men of Erin
left the task incomplete, saying: ". . . since darkness has
fallen upon our work, and night has come on and the day is gone,
let each depart to his place. Dubad (darkness) shall be the name
of this place for ever."
Given that there
are seven "suns" on
kerb 51, and that the mythology about Dowth speaks of a bull
and seven cows, it seems likely that the site has some connection
with the constellation of Taurus, the Bull, which contains the open
cluster the Pleiades, otherwise known as "The Seven Sisters".
This constellation was very important around the time the Boyne
Valley mounds were being constructed, as it contained the Sun on
the Spring Equinox, that very important moment of the year when
the Sun's path along the ecliptic crossed the celestial equator
heading northwards. It is the Sun's position among the zodiac
stars at this time which determines the current 'age' - i.e. the
"Age of Taurus".
phenomenon which occurs at this time is what is known to astronomers
as a 'heliacal rising' of the Pleiades. This happens when the stars
in question rise at the eastern horizon but are quickly lost in
the glare of the rising sun. It is interesting to note that the
Egyptians, and the Dogon tribe in Africa, among others, used the
same Dowth-like 'sun-wheel' symbols to signify a heliacal rising.
If these 'sun-wheel'
symbols do represent the heliacal rising of the Pleiades, it could
tell us something very significant about the Neolithic people -
they were aware of the great cycle of precession, the slow wobble
of the Earth's axis which causes the celestial pole to shift over
time, resulting in the Vernal Equinox point, that place where the
Sun crosses the celestial equator, moving backwards, or westwards,
through the Zodiac over a huge 25,800-year period. This Vernal point
moves just one degree (about two widths of the full moon) every
72 years, and spends on average 2,150 years in each of the twelve
constellations of the Zodiac.
function of Dowth is not in question. In 1980, Martin Brennan, who
suspected the southern passage and chamber was aligned on the Winter
Solstice sunset, gained access to the chamber, and with the help
of some fellow enthusiasts, he filmed the beam of light from the
Winter Solstice sunset as it reached forth across the floor of the
chamber and struck the bottom of one of the decorated chamberstones.
This few minutes
of 8mm cine film, which I had the rare chance to view just over
a year ago, helped along with other discoveries in that year to
prove something which Brennan had believed from the time he had
begun his research into the Neolithic sites - that Newgrange did
not exist in isolation as an astronomically-aligned structure.
Solstice alignment of Dowth South has in recent years become
the focus of study for artist and author AnneMarie Moroney, who
has spent the last four winters recording, photographing and studying
She says that
From November to February the rays of the evening sun reach into
the passage and then the chamber of Dowth South. During the winter
solstice the light of the low sun moves along the left side of the
passage, then into the circular chamber, where three stones are
lit up by the sun. The convex central stone reflects the sunlight
in to a dark recess, lighting up the decorated stones there. The
rays then recede slowly along the right side of the passage and
after about two hours the sun withdraws from Dowth South. Interestingly,
she also says that the builders of the passage mounds seemed to
realise that the human eye would be harmed by watching the sun directly.
By directing the sunbeams through a small opening, the slightest
changes in the position of the sun could be observed safely. The
too may be astronomical in function, although an entrance shaft
erected in more modern times prevents any sunset from being watched
from within the passage. Some researchers have suggested it is aligned
on the cross-quarter
day sunsets on November 8th and February 4th, and Anne-Marie
Moroney has carried out some preliminary measurements and studies
which would back up this idea.
passage is inaccessible to the public, and was disturbed in the
early Christian period by the construction of underground storage
chambers called souterrains. However, those lucky enough to know
someone with connections in the world of archaeology who can access
a key to the gate of the Northern Passage, are in for a treat. That's
exactly what I got when I in November of 2000. The chamber of Dowth
North is an eerie place to be. Hidden from daylight, and sunken
into the ground, it is cold, dark and claustrophobic. The modern
electrical lights do not work, the chamber is currently only accessible
through a 70-foot souterrain, and the passage orthostats lean together
such that when you walk up the passage, you have to squeeze through
the stones. It's a strange experience, to say the least. But Dowth
North could be the oldest cruciform passage in the Brugh na Bóinne
area, and it is well worth a visit.
passage and chamber seem to be older in date than Newgrange, and
possibly Knowth, due to the fact that the passage at Newgrange is
more advanced, with water drainage techniques incorporated into
its roof structure which were not found at Knowth. The interior
of Dowth North seems to carry on the astronomical theme present
on some of the great kerbstones outside the mound. The chamberstone
C7 is particularly well decorated, featuring a number of stellar
symbols, concentric circles, a small spiral, linear markings and
other features such as small inverted V shapes.
astronomical theme was also picked up by George Coffey, keeper of
Irish antiquities at the National Museum, a century ago. Coffey
noticed that many of the star/sun symbols at Dowth were repeated
at Newgrange and Loughcrew. Perhaps at some time in the future,
the concrete shaft will be removed and once more the light will
be allowed into Dowth North. For the time being, it remains off
bounds even to the sun.
a number of white quartz stones have been found near what would
have been the original entrance to this passage, and this could
be another link with the Moon-Milky Way theme which we picked up
on earlier at Newgrange. Dowth is also known in legend as the place
where Boann is buried - perhaps this was a reference to the Full
Moon shining into the Dowth chambers before setting, once more plunging
the place of darkness into, well, darkness.
There have been
some suggestions in recent times that there may be a third passage
at Dowth, on the eastern side. Just to the left of the Stone of
the Seven Suns is a very interesting kerbstone featuring a vertical
line down the centre. Other entrance kerbstones, such as Kerbstone
1 at Newgrange and the entrance kerbstones at Knowth's two passages,
feature a vertical line. With no major excavations planned at Dowth
in the near future, it seems unlikely that we will know if there
is a third passage for the time being.
One other archaeological
site near Dowth is extremely worthy of a mention. Labelled Site
Q on archaeological maps, it is a structure known as a henge, or
an embanked enclosure. It is said by some to be the second largest
such ringed structure in Ireland.
ring through its southwestern opening, the huge scale of the site
and the height of the surrounding banks give one the impression
of a giant ampitheatre. If this was some kind of ceremonial site,
it certainly smacks of grandeur and hugeness. There is a second
opening, to the northeast of the ring, which may or may not have
been contemporary with the construction of the site. But if one
stands outside the structure, to the southwest, and lines up the
two entrances, this is the exact line of Summer Solstice sunrise,
an event which I have been witness to. Regrettably, it will take
an actual excavation of the site to discover if both openings were
contemporary with the original design of the site, but even if that
northeastern entrance turns out to be a 19th century agricultural
breach, the alignment raises the interesting, and somewhat speculative
suggestion, that perhaps the southwestern entrance may have allowed
viewers in the centre of the ring structure to accurately view Winter
Solstice sunset, perhaps as part of some major ritual event. From
the air, Site Q is egg-shaped, just like Newgrange, and the fact
that it may share a Winter Solstice sunset alignment with nearby
Dowth is interesting indeed.
the Place of Darkness where the Winter sun sets, we must now turn
our attention to the third great Brugh na Boinne mound, Knowth,
which has in recent years been causing great excitement in the fields
of both archaeology and astronomy. In the 1960s, Knowth was just
a large mound in a field, with no sign of any stones visible. Since
then, under the direction of Professor George Eogan, the whole site
has been thoroughly excavated and has thrown up more than its fair
share of treasures, decorated stones, surprises and mysteries.
the biggest reason Knowth has caused such a sensation is its plethora
of megalithic art. The site contains well over a quarter of all
megalithic art known to exist in Europe, and many of its 127
kerbstones are decorated, some highly so. Knowth also has two
passages, facing east and west. In our astronomical exploration
of Knowth, we first turn to one of the most exciting stones in the
Boyne Valley - the kerbstone which was named the "Calendar
Stone" by Martin Brennan.
kerbstone at Knowth proves that the people of the Neolithic were
competent astronomers, who had made observations over great periods
of time, and were able to pass on their astronomical knowledge from
generation to generation. The Lunar Stone presents a format that
can be used to track the synodic month, and from it we can obtain
very important calculations of large subunits of the Lunar, or "Metonic",
What this stone
demonstrates is that the Neolithic people who constructed the mound
were aware that the solar year, which is 365 days long, does not
contain an equal number of synodic periods of the Moon. But it also
shows they were aware of the great 19-year Lunar Cycle and studied
the movements of the moon over long periods of time.
A synodic period
of the Moon is marked by the return of the Moon to the same phase,
and is exactly 29.531 days long. So therefore, 12 lunar months,
or 'Synodic months' is exactly 354.372 days long. But this is a
whole 11 days shorter than a tropical year. The Neolithic mound-builders
knew this, and used the Lunar Stone to record their calculations
of the numbers of synodic lunar months in tropical years.
25 synodic months is 738.275 days, which is 8 days longer than 2
37 synodic months is 1092.647 days, 3 days short of 3 tropical years.
49 synodic months is 14 days shorter than 4 tropical years.
62 synodic months is 5 days longer than 5 tropical years.
It is this value
in the sequence which is represented on the lunar stone at Knowth.
There are a total of 31 'waves' across the stone, surrounded by
representations of the Moon - 29 of them - representing the 29 days
of the synodic lunar month. If we double the number of waves, we
get 62, representing 62 synodic periods of the Moon, which, as we
have already seen, is just 5 days longer than 5 tropical years.
The sequence continues until we get a very close correlation between
synodic months and tropical years: 99 synodic lunar months is only
2 days longer then 8 tropical years. But even closer still is 136
synodic months, which ends about a day before 11 tropical years.
And if we add 99 synodic months to 136 synodic months we reach the
"Metonic Cycle": 19 tropical years is equal to 235 synodic
lunar months, or 254 tropical lunar months. A tropical lunar month
is defined by the amount of time it takes the Moon to reach the
same background stars again - it is equal to 27.322 days. The Metonic
Cycle gets its name from a Greek called Meton who lived in Athens
in the 5th century BC, and who claimed he discovered this cycle
of the Moon himself based on simple observations. Based on our studies
of the Lunar Stone at Knowth, we now know the "Metonic
Cycle" was known about long before Meton ever existed.
it is highly possible that this kerbstone was used to calculate
the exact number of days in the tropical solar year. There are 29
moons in total, 22 crescents and seven circular moons which are
really double circles, and potentially signifying an extra count.
There is a folk tale still in existence from Brittany to Scotland
which says that you should never count stones more than once because
you will never get the same number. The numbers and arrangements
at Stone Age sites were chosen so that there were several ways of
If we count the moons, to get 29, and add the second set of circular
moons, we get 36. If we double 36 (and the stone already suggests
doubling with the waved line - 2x31=62) we get 72, and add the solar
spiral, we get 73. 5 times 73 is equal to 365, the exact number
of days in the year. Every fourth year, add the solar spiral to
get 366. Another 'Lunar Stone' at Knowth can also be used to calculate
the exact length of the year, as well as both the siderial and synodic
line" feature can also be seen to have supplemental counts
on the left side, continuing from 31 to 32, 33 and 34. 32 synodic
months is also a significant subunit of the Metonic Cycle, because
when doubled it becomes 64 synodic periods which ties in with five
calendar synodic periods of Saturn. 33 synodic months is one-third
of the very important metonic subunit: 99 synodic periods ends just
two days after eight tropical years. And 34 is one-quarter of another
large Metonic subunit: 136 synodic months ending about one day before
11 tropical years.
can also be used to calculate the lengths of the siderial and synodic
lunar month, and the solar year. I call it the "Lunar Stone".
In our look at this 5,300-year-old astronomical puzzle, we will
interpret the symbols as follows: the crescent shapes are early
and late phases of the moon; the circles are lunar phases close
to full moon, the small spiral with a single crescent to the right
represents the way the count is carried out, as identified by Martin
Brennan; the wavy line represents numbers of lunations, or months,
while the line underneath is a calibration bar marking a specific
number of lunations or months.
The 27-day count
begins on the extreme right of the stone, working towards the right,
a total count of 11 crescents. The eighth phase is marked with a
line to indicate a quarter moon. Then the three concentric circles
are added to the count, making a running total of 14. Working backwards,
we don't count the centre circle because it marks the turning point
of the count, and work outwards, adding another two circles, total
16, and then the 11 crescents again, totalling 27. This first method
of counting reveals the siderial month, the length of time it takes
the Moon to make one complete circuit through the sky, in other
words the time it takes the Moon to return to the same background
count works in a similar way, but this time, in addition to counting
the outer two concentric circles of the triple circle, the additional
double concentric circle on the far top left of the stone is also
counted. So we have (working inwards) 11 crescents, plus three circles,
total 14, and (working outwards) add two circles, plus another two
circles, total 18, plus the 11 crescents again, totalling 29.
This, I believe, is the Synodic Lunar Month count.
While the Siderial Month marks the Moon's return to the same background
stars, the Synodic Month marks its return to the same phase. Both
are important in calculating the 19-year Metonic Cycle. There are
235 synodic months and 254 siderial months in the Metonic Cycle.
Interestingly, another Irish researcher, Gillies MacBain, has pointed
out that the original total number of kerbstones around Knowth,
127, is half of 254, or half the number of siderial lunar months
in one Metonic Cycle. Could the whole site have been one large astronomical
calculator, with complex movements of the Moon seemingly figured
out and recorded for time??
As with the Calendar Stone, the Lunar Stone can
be used to work out the length of year. It involves a simple calculation,
using the stone as a guide, and the result is accurate. The length
of the Synodic Lunar Month is 29.5 days, and if we do as the stone
suggests (in the waved line calibrated count of 12) and multiply
the synodic period by 12 (in other words 12 lunations), we get 354.37
days, which is 11 days short of a complete year. One final addition
of the 11 crescents will result in the accurate answer of 365 days.
Another very well adorned kerbstone, number 15,
seems to contain a combination of a large sundial device and a series
of markings designed to help calculate the length of the year. Neil
L. Thomas, in his study of the Irish Stone Age symbols of 3,500BC,
believes he has identified the manner in which this stone device
Thomas says the stone is a unique statement, an
exact 365-day, siteen month, four week month, five day week solar
calendar. Brennan identified the large fan-like rayed device on
this stone as being a sundial, and stressed the importance of the
study of the sun's movements to the people who he called the "master
diallers of the New Stone Age". Their dials were constructed,
he says, so that they could tell time precisely, even to fractions
of a second, but this was for the purpose of making exact observations
simultaneously in different places.
There is another sundial
at Knowth. It is carved onto the top of a kerbstone on the northeastern
side of the mound. On the sundial at equinox, the sun rising in
the east casts its shadow west, at midday it casts its shadow north
and, as it sets, it casts its shadow east, completing a cross in
its circle and defining time and space simultaneously. Brennan says
the dial measures what are known as the unequal or 'planetary' hours,
which are shorter in winter and longer in summer. At the equinoxes
it divides the day into 8 equal parts, which are further subdivided
into 16 parts. This corresponds to the solar division of the year
into 8 parts.
There is another type of dialling
device at Knowth, outside the entrance to the western passage.
It is a strangely shaped standing stone, which casts an interesting
shadow at an interesting time of the year.
Frank Prendergast said that measuring the shadow
cast by a vertical pole, or gnomon, is known to have been used as
a simple astronomical instrument from which the approximate time
of day or even the altitude of the sun at local noon can be deduced,
leading to a reasonably accurate definition of north-south.
Perhaps the builders of Knowth knew the value of
gnomon shadows, because on the evening of maximum penetration of
the setting sun into Knowth West, March 3rd, the standing stone
casts a shadow on the entrance kerbstone. It does this for a number
of evenings at certain times of the year, but it is on the day of
maximum penetration that the shadow appears to line up against the
central vertical line of the entrance kerbstone just as the sun
sets. I managed to catch the progression of the shadow on film,
and the result is interesting. Just as the sunlight is penetrating
deep into the western passage, the gnomon shadow lines up perfectly
with the vertical centre line on the entrance kerbstone. When it
hits the stone, the setting sunlight becomes diffuse and the shadow
As the shadow event is happening outside, something
very familiar is happening inside Knowth West in early March and
early October. The long rays of the sun penetrate into the passage
and illuminate the darkness, revealing a wealth
of decorated stones inside.
Although similar to the Winter Solstice illumination
of Newgrange, the Knowth West illumination has not been sufficiently
recorded or publicly documented to show exactly how far beyond the
bend in the passage that the sunlight actually penetrates.
Until I took this photograph from inside the western
passage around sunset on the Autumn Equinox two years ago, I had
never seen a photo of this phenomenon. And even this photo does
not do the event justice - this was taken just as the sun was being
covered by a large bank of cloud in the west, and moments after
I took this picture the sunlight disappeared.
Because the western passage is oriented somewhat
south of west, to about 260 degrees azimuth, it is not aligned on
the equinoxes as some have claimed, but rather 18 days before the
Spring Equinox and 18 days after Autumn Equinox. An American astronomer
and researcher, Charles Scribner, has put forward a new theory as
to how the alignments functioned. Read
If all of that wasn't enough to whet your astronomical
appetite, there's always the work of planetary cartographer, Philip
Stooke of the University of Western Ontario, Canada, who claims
to have discovered a map of the Moon carved onto one of the stones
inside the chamber of the eastern passage at Knowth.
spends most of his time preparing maps of asteroids based on spacecraft
observations, but he has also prepared detailed maps of the Moon,
and it was this field of study which made his eyes light up when
he first saw a drawing of the carving in an archaeological book
about Knowth which he read in Canada. He told BBC Science Correspondent
David Whitehouse recently: "I was amazed when I saw it. Place
the markings over a picture of the full Moon and you will see that
they line up. It is without doubt a map of the Moon, the most ancient
one ever found." And all from thousands of miles away. In fact,
Philip Stooke confirmed to a journalist colleague of mine that he
has never been to Knowth. But he plans to visit to see the lunar
map for himself.
If his claim is true, it may lend some weight to
the argument that neolithic stone passages could have been used
to track down Moonrises and Moonsets. In this case, the light of
a full Moon rising in the east may once have shone into the eastern
passage of Knowth and illuminated the map in the end recess. Who
knows?? Later phases of activity at Knowth took their toll - in
the early Christian period the construction of souterrains seriously
altered the entrance to the eastern passage, and modern archaeological
reconstruction has seen the addition of a huge concrete slab at
the entrance, so we may never know the full extent of any astronomical
alignment the passage might have had.
One thing is certain - Knowth is an astronomical
site, and there is a wealth of discoveries which have yet to be
made there. There are huge amounts of astronomical symbolism carved
into its stones, so much in fact that to say Knowth is does not
have astronomical functions is tantamount to missing the point.
Some of these great stones and carvings are accessible to the public,
through organised tours which start at the nearby Brú na
Bóinne visitors centre. I would strongly encourage you to
go and have a look for yourselves, it really is a wonderful experience.
/ SLIABH NA CALLAIGHE
Before we finish
our wonderful exploration of Stone Age astronomy, we must leave
the Bend of the Boyne for a moment and turn our attention further
west, towards the hills of Meath at a place called Sliabh
na Caillaighe, the Mountain of the Hag, at Loughcrew. Here,
scattered on the peaks of the Carnbane hills which overlook some
breathtaking scenery, are a group of Stone Age cairns which may
be even older than their Boyne Valley counterparts.
It was here,
at one of the cairns called Cairn T, that Martin Brennan made a
discovery in the Spring of 1980 that was to put him on the front
page of newspapers across the world. Cairn T, at over 900ft above
sea level, stands in the central position and takes the most prominent
place on the highest summit of a megalithic area that may once have
contained as many as fifty to a hundred cairns. It was March 17,
1980, and Brennan and his friend Jack Roberts had just arrived at
Cairn T after a drive from Dublin. This was the latest in a string
of attempts to see the sunrise, but adverse weather conditions that
Spring meant they had not seen one single sunrise since March 1st.
Here is Brennan's
account of what happened:
winding up the mountain road when the disc of the sun broke on the
horizon. We felt as if we were ten minutes late for an appointment
made over 5,000 years ago. The lock on the modern door leading to
the passage had frozen during the night, and as we struggled with
it the rising sun was already above the horizon. When we drew back
the door a narrow chink of light streamed down the passage and flashed
into the end recess of the chamber."
upper left of the backstone a rectangular patch of light was rapidly
beginning to take form, brilliantly illuminating the entire chamber
in a growing splendour of shimmering golden orange light. It was
dazzling, and when we entered the chamber we stood back and gazed
assumed a clearly defined geometric shape that was projected on
to the upright backstone and moved diagonally across it, tracing
the path of the sun against a mural of prehistoric art. What impressed
us most was the careful and delicate modelling of the light beam
by the huge stones forming the passage and chamber, and how the
shape of the beam conformed to the patterns engraved on the stone.
For the first time we were seeing the signs and symbols in the context
in which the artist had meant them to be seen."
it was clear that they were dealing with a solar construct capable
of defining an individual day with far greater precision than Newgrange.
The wider differences in the sun's apparent movement at equinox
made it considerably easier to define the actual day of equinox
at Cairn T than the day of Winter Solstice at Newgrange. Coupled
with the help of the rock engravings, this created a remarkably
precise asonomical instrument.
The stone which forms the ceiling of the end recess
of Cairn T is also beautifully adorned, and contains a number of
star-like and sun-like patterns. This stone, too, would receive
reflected light on the morning of the equinox. Crouched in the small
recess, with one's face to the entrance and one's back to the beautiful
equinox stone, looking up at the ceiling gives one the impression
of looking at some kind of star map or astral guide. Sunwheels,
most notably those with 8 radials, echo the pattern of sunwheels
on the equinox stone. This highly-decorated stone, along with one
on the ceiling of the east recess at Newgrange, was engraved before
being positioned above the recess.
Some of the passage stones at Cairn
T are adorned with huge numbers of round holes, or cup marks,
and give the impression of some form of primitive star map.
Another interesting aspect of the Cairn T alignment
is the fact that when you look out from the end recess through the
entrance, the distant Hill
of Slane can be seen in the centre of the view. In other words,
the Spring Equinox sunrise viewed from Loughcrew Cairn T rises at
Slane. Was this another intentional alignment? Is it merely coincidence
that Saint Patrick was later to light his Easter fire here, and
that Easter is calculated using the Full Moon closest to the Spring
Equinox? Also coincidental is the fact that St. Patrick's Day is
celebrated three days before the Spring Equinox in modern times.
There is a large mound on the peak of the Hill of
Slane, although many visitors do not see it because it is shrouded
in a clump of huge trees and access is difficult. This mound was
said to have been the burial place of the Fir Bolg king Slaine,
who reigned in the ancient province of Ulster, which at that time
was the largest of the five provinces in the country. His territory
was bounded to the south by the River Boyne, which in ancient times
marked the border between the provinces of Ulster and Leinster.
It was in Drogheda, at a mound known today as the
Millmount, that the mythical Milesian rulers Eremon and Eber divided
the island into two kingdoms - one north of the Boyne and one south.
The mound later became the burial place of Eremon's brother, the
bard and astronomer Amergin, who famously chanted these lines when
the Milesians first landed at the Boyne Estuary:
"What land is better than this island of the
Who but I knows the place where the sun sets?
Who but I can tell the ages of the Moon?"
It seemed that Amergin and his brothers were well
aware of the Boyne River's long-established link with astronomical
study. Another curious alignment worthy of mention brings some of
these ancient sites into focus. A line drawn on an ordnance survey
map from Millmount through the Slane mound can be traced with reasonable
accuracy as far west as Loughcrew, and specifically Carnbane west
which contains a number of neolithic sites. If this supposed alignment
seems imaginative, it gains credence when one considers that from
Millmount, Winter Solstice sunset occurs exactly in the direction
of the Hill of Tara and another ancient mound, the Mound of the
Carnbane west, the apparent target of the alignment,
contains the biggest Cairn of all the cairns at Loughcrew, called
Cairn D. But it is a nearbly heap of stones, Cairn L, which attracts
more astronomical interest. It is inside the chamber of Cairn L
that on the November and February cross-quarter days, sunrise penetrates
into the chamber and illuminates a 6-foot tall white standing stone.
event was first rediscovered by Brennan on November 3rd, 1980. He
describes it thus: "A flash of light pierced the darkness of
Cairn L and illuminated the top of the standing stone. Instead of
the usual slow, progressive entry of the beam of light, it had penetrated
the chamber instantaneously." He said the beam of light was
modelled so that it struck only the standing stone, and no other
stones. He had witnessed precise astronomy at work, some 5,700 years
after this Stone Age timepiece was put together.
There are other alignments at Loughcrew too. The
direction of Summer Solstice sunrise is marked by the lining up
of four sites - Cairns P1, R2, T and U. Cairn I, which points to
Cairn T, can be used to track the sun as it makes it way towards
the equinox, while cairns S and U are aligned on the cross-quarter
day sunrises, Cairn S on May/August cross-quarter, and Cairn U on
November/February cross-quarter. Moonrises have also been observed
at Loughcrew, and the most interesting of these is the Harvest Moon
in August which shines into Cairn L and strikes stone 13 at the
back of the end recess.
/ BAILE TRÁ
Before I conclude,
there is one more site worthy of a mention. It is at Baltray,
a village at the Mouth of the River Boyne, where we meet two megalithic
standing stones, which have stood as silent sentries watching over
the estuary for thousands of years. The larger of these two standing
stones has a very flat, straight edge, which myself and two friends
discovered had a very unique alignment.
stone points to two small islands out in the Irish Sea, called Rockabill,
which in modern times have a lighthouse on the larger of the two
islands. In December of 1999, we confirmed, after much speculation,
that this was the location of the rising sun at Winter Solstice
as viewed from the Baltray standing stone.
The alignment is a bit off in this epoch though, and the sun's rising
position has drifted to the left in the years since the stones were
erected. We are not sure exactly when the stones date to, but we
suspect they are early indeed, perhaps as early as the Late Neolithic,
which would place their construction some time between 3000 and
2500 BC. At least one prominent archaeologist has agreed that this
might be the case. We know at Newgrange, thanks to the work of Frank
Prendergast and Tom Ray, that the sun's rising position now is a
whole degree, or two sun widths, to the left of where it was when
Newgrange was constructed, and it is clear that at Baltray the sun's
rising position is at least one and a half sunwidths left of Rockabill.
We would prefer to leave it to the professional archaeoastronomers
to tell us exactly when the stones date to, but it is sufficient
to conclude that the alignment is of major importance.
is the first major archaeological site one would encounter on a
journey up the Boyne River, and because of the major astronomical
theme of the many Stone sites along the river, it must be considered
important that the very first site has a Winter Solstice sunrise
alignment just as Newgrange does. These stones would have been important
as a boundary marker in ancient times, marking the border between
the ancient provinces of Ulster, to the north of the Boyne, and
Leinster to the south. Legend tells us this is the strand where
Cuchulainn met his son
Connla for the first time and the two fought on the shore of the
sea under the standing stones before Cuchulainn slew his son in
the shallow waters of the incoming tide.
The stones may
also have been used to track the position of the Moon, as is suggested
in another myth about Rockabill which tells how the Sun god, Balor,
was once trying to steal the magic cow, the Glasgabhlin, from Ulster.
This cow, the story says, had an everlasting supply of milk. I have
tentatively linked this cow with the Moon, and the calf with Venus,
suggesting that the astronomical purpose of the stones is more complex
than meets the eye. See more about the Baltray myth
To the casual
or foreign visitor, there is something awe-inspiring about the huge
megalithic sites of the Boyne region. Very few people leave Brugh
na Boinne without having felt some deep connection with the ancient
past, and fewer still leave without a clatter of questions on their
mind about the original intent and purpose of these sites.
For the astronomer,
these are surely exciting places to be. In one moment, an amateur
astronomer visiting Dowth or Loughcrew or Fourknocks or Newgrange
can bridge up to five and a half thousand years of history. For
just as we today gaze at the heavens and watch the sun, moon, planets,
and stars, so too did our ancient ancestors. Of that, we are now
a consensus is beginning to form, even in the more conservative
areas of archaeological and anthropological academic research, that
much of what the people of the Irish Neolithic were about involved
some form of heavenly study or knowledge. The field of ancient astronomical
research, once left almost entirely to amateurs, is now very much
a part of professional study of these sites.
And this is
a good thing. If we can begin to look at our ancient sites as being
connected, whether astronomically or otherwise, we can begin to
see the Cosmic landscape, in much the same form as it was originally
crafted, by people who felt a connection with the Cosmos in a much
stronger and definite way than we do. We may have discovered more
planets, put a man on the Moon and seen into the furthest reaches
of space with our telescopes, but we have lost something too - a
simple, but beautiful, relationship with the heavens which understands
the harmony of the sun and the seasons, the moon and the tides,
and their movement among the stars which reveals the longer ages
in which things slowly change.
landscape functions on more than simply one or two levels. It is
what I call three-dimensional, and each site demonstrates this perfectly.
At Newgrange, to take the most famous example, some would believe
that it is a device for tracking down Winter
Solstice. That is not the full picture. Newgrange is a complex
astronomical and calendrical device. The people who constructed
it knew this better than we do, and could probably tell exactly
what day of the year it was simply by looking at the way the sun
casts shadows on the stones. We have taken that simple observation
away, and replaced it with wristwatches, and calendars, and computers
and a host of devices and aids with which we can tell the day, or
season, or year.
The people who
built Newgrange, and Knowth and Dowth as well, were very familiar
with the lunar cycle. We know they studied the Moon's cycle because
they wrote about it on the stones, in a language which seems vague
and complex, but which can be interpreted symbolically by those
who care to look hard enough.
And our understanding
of their exact level of knowledge is still poor. There remains much
work to be done. Tonight, we have seen an astronomical interpretation
of three or four kerbstones at Knowth. There are 127 in total, and
many more decorated stones in the passages.
Maybe at some
stage we will know and understand, and see the universe in much
the same way as the megalithic astronomers. Until then, the journey
of discovery and enlightenment is an exciting and fulfulling one.
Murphy. This lecture was delivered to members of Astronomy
Ireland at their monthly lecture in DCU in January 2002.
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