Has the Mystery of Stonehenge’s Purpose Finally Been Solved? 3D Laser Scanning Shows Stones Were Aligned with the Sun to Light up an Art Gallery
Mark Prigg, Daily Mail (London), October 8, 2012
Stonehenge was designed to light up carvings as though they were on display in a modern museum, a groundbreaking 3D scan of the iconic stones has found.
The latest 3D laser technology revealed new evidence of the importance of the midwinter sunset to the ancient creators of Stonehenge, along with 71 new images invisible to the naked eye due to weathering of the stone.
It suggests that the stonemasons used the best materials where the rays would hit the stone, ensuring they would glisten in the final light of the setting winter solstice sun, or at dawn on the longest day.
The laser scan has also revealed many more prehistoric carvings, including 71 new images of Bronze Age axe heads chipped into five of the giant stones, bringing the number of such carvings discovered at Stonehenge to 115.
The previously unknown Early Bronze Age carvings are invisible to the naked eye.
To find them, researchers analysed 850 gigabytes of information.
3D scanners were used to record billions of points micro-topographically on the surfaces of the monument’s 83 surviving stones.
Detailed analysis of that data carried out on behalf of English Heritage found images had been engraved on the stones.
This was usually done by removing the top 1-3 millimetres of weathered (darker coloured) rock, to produce different sized shapes.
Although now largely invisible to the naked eye, back in the Early Bronze Age the images would have been clearly visible on unweathered stone.
The varying techniques and amounts of work confirms not only that the builders intended to align the monument on the axis of the sun at midsummer and midwinter, but also that the view from the north east was particularly important.
Researchers said it was clear the stones were meant to be approached from the north east up the ancient processional avenue towards the direction of the midwinter sunset.
Approaching and viewing the stone circle from this direction meant the winter solstice sunset had particular importance to prehistoric people, and efforts were made to create a dramatic spectacle for those coming from the north east, experts said.
The stones in the outer circle which could be seen on the approach from the north east have been completely ‘pick dressed’, removing the brown and grey crust of the rock on the surface to reveal the bright, grey-white underneath.
But the outer faces of those on the other side of the outer circle were not worked in the same way.
The stones facing the north east are also the largest and most uniform, and the lintels are very well-worked and finished compared to those elsewhere in Stonehenge.
Stones that flanked the north east/south west axis of the summer and winter solstices were most carefully worked to create straight and narrow rectangular gaps.
The researchers said that as other stones in the monument have more natural, less neat outlines, it seems that the creators were making a special effort to allow a dramatic passage of sunlight through the stone circle at midsummer and midwinter.
Professor Clive Ruggles, emeritus professor of achaeo-astronomy at University of Leicester, said: ‘This extraordinary new evidence not only confirms the importance of the solstitial alignment at Stonehenge, but also show unequivocally that the formal approach was always intended to be from the north east, up the avenue towards the direction of midwinter sunset.
‘We see how the utmost care and attention was devoted to ensuring the pristine appearance of Stonehenge for those completing their final approach to the monument at the two times of the year when sunlight shines along the alignment – when those approaching had the midsummer rising sun behind or midwinter setting sun ahead.’
English Heritage said the new presentation of Stonehenge, which includes a new visitor centre 1.5 miles away out of sight, involved closing the A344 to reunite the stone circle with the avenue from which it was meant to be approached.
[Editor’s Note: Pictures of the laser imaging and axe etchings are available at the original article link below.]