Oct. 12, 2012
-- It might look like just an ordinary picture of Stonehenge, but this is how the creators of the prehistoric monument wanted the site to be viewed, according to research using the latest 3D laser scanning technology. The groundbreaking analysis determined that the prehistoric monument was built to show off the solstices. In this view Stonehenge would look best when approaching from the Avenue, its ancient processional way to the north east.
Commissioned by the English Heritage, the laser-scan survey revealed in unprecedented detail the efforts made by prehistoric people at Stonehenge. "The result of the project were beyond all expectations. The investigation identified traces of stone working on virtually every stone," Marcus Abbott, head of geomatics and visualization at ArcHeritage, Hugo Anderson-Whymark, an Oxford-based expert on ancient worked stone, and colleagues wrote in the English Heritage report.
The laser-equipped researchers investigated the entire site. The laser scanner collected data with a resolution of 1 mm across the entire stone circle, and of just 0.5 mm for four stone surfaces of special interest. More than 700 surface features came to light.
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The laser highlighted prehistoric carvings from 4,500 years ago as well as damage made by modern visitors. Along with modern graffiti, this image shows scores of little axe heads and a possible dagger added when the slabs were already 1,000 years old.
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Overall, the laser scanning revealed 71 new Bronze Age axe heads, which bring the number of this type of carvings known at Stonehenge to 115.
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But the most interesting findings came from analysis of the stone surfaces. The study showed that the techniques and amounts of labor used varied from stone to stone. According to the researchers, these variations provide almost definitive proof that it was the intent of Stonehenge's builders to align the monument with the two solstices along a north-east/south-west axis. Indeed, the extremely straight and neat outline of the Great Trilithon, compared with all the other trilithons, shows that Stonehenge creators made deliberate efforts to shape it more carefully due to its special position on the solstice axis, just as they did for other stones that flank this axis.
The laser scanning showed that sides of the stones that flanked the solstice axis were most carefully worked to form very straight and narrow rectangular slots. To make them glisten in the sunlight, some stones had their crusts removed. These stones include two of the north-east facing sarsens in the outer circle, the Great Trilithon in the inner sarsen horseshoe, and an isolated upright stone in the south-west segment of the outer circle. By contrast, the stones in the south-western segment of the circle did not have their crusts removed.
The specially smoothed slabs created a dazzling light effect when the sun rays hit the stones. They would glisten in the dawn light on the longest day of the year and at sunset on the shortest This drawing shows Stonehenge in about 2300 B.C., after the construction of the sarsen outer circle and trilithons. Note the solstice axis.
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Remains of a baby dating back to 3,000 years ago have been found at a site in Ireland that is believed to be the birthplace of Halloween.
The fully intact skeleton, possibly belonging to a 7-10 month child, was unearthed during a three week excavation at Tlachtga, on the Hill of Ward near Athboy Co. Meath.
One of Ireland’s most enigmatic sites, the Hill of Tlachtga features impressive circular earthworks which are best seen from the air. Medieval texts link the site to Samhain, the ancient Celtic Festival which is the precursor to modern Halloween.
“We may never know what caused the death of the child. The skeleton probably dates back 3,000 years and was found on the bedrock at the base of a 1.5m (3-foot, 28-inch) ditch,” lead archaeologist Stephen Davis, at University College Dublin, told the Irish Examiner.
Excavation and surveys carried out using airborne laser revealed the area was a “key ritual site.”
“The site has several different phases of monumental enclosures and we believe them to be associated with festivals and rituals potentially dating back as far as 1,000 B.C.,” Davis said.
Sitting on top of the Hill of Ward, Tlachtga is a site steeped in folklore. According to Irish mythology, it got its name from the daughter of the powerful druid Mug Ruith. According to legend, the remains of the druidess, who is said to have died on the hill after giving birth to triplets, are buried there.
Tlachtga is also believed to be the site of the Great Fire Festival in which sacrifices were offered to gods on Samhain eve. All hearth fires throughout Ireland were extinguished and then lit again from a central fire on the hill.
Meaning summer’s end, Samhain was a great festival of the dead — a time when the doorways to the otherworld opened and journeys could be made from one side to the other.
The veil between the worlds of the living and the dead was believed to be the thinnest on Oct. 31, a day which lies exactly between the autumnal equinox and the winter solstice.
The excavation revealed the monument of Tlachtga is actually the last of at least three phases of enclosure on the hill.
“As a working model for the phases of construction, at least one small enclosure, about 15 inches in diameter, was enclosed by a very large, tri- or quadrivallate enclosure, about 650 feet in diameter, which was replaced by the monument we see today,” the archaeologists said.
The excavations also brought to light evidence of burning, which could have been ritual fires or the result of glass-making, Davis said.
He believes the child was most likely not the victim of any human sacrifice on the ritual site.
The remains have been taken to the School of Archaeology at University College Dublin for further examination.
Image: Tlachtga from the air. Credit: Excavations at Tlachtga via Facebook