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U.S. Mounds Called Oldest Celestial Calendar
By Philip J. Hilts, Washington Post Service

Washington ­ Ancient earthworks in Louisiana may be the world's largest astronomical calculator, according to recent discoveries by two scientists who have studied the ruins for years. The 3,800 year old earthworks in north-eastern Louisiana are arranged in six great octagons, one inside the other, with passages radiating out of all eight corners. The whole monument, made of dirt ridges, measures about three quarters of a mile across. Each of the eight sides of the outermost octagon is about 1,300 feet long.

The best known of the ancient astronomical calendars in the world is Stonehenge in England. But the ring of stones that makes up Stonehenge's calendar, by comparison, is only a few hundred feet across. The great monument at what is called Poverty Point, Louisiana, was built by people who carried basketfuls of dirt and heaped them up to form the ridges that make the sides of the octagons. The scientists say half a million cubic yards of dirt must have been moved to make the octagons, making it the most massive of all monuments in the ancient world. It is lower but much more massive than the great pyramids of Egypt, according to archaeologist William Haag, who recently retired from Louisiana State University and has studied the Poverty Point structures for 25 years.

The unusual ridged mounds at Poverty Point have been known to archaeologists since the turn of the century, but the array is so large that the concentric octagons could not be seen until 1954 when the first aerial photos were taken.

"Then the whole earthwork just appeared to us," Mr. Haag said, "We were aware of the ridges, but the magnitude of them never entered our heads, or that they were man-made, until we saw those pictures,"

Special Positions

It was not until the mid-1970's that Mr. Haag began to think that this great array was not only manmade, but might serve as an astronomical calendar as the Stonehenge monument does. In the last two years he and astronomer Kenneth Brecher of Boston University made of measurements and calculations to check the idea.

Mr Haag said that if an observer stands in the middle of the earthworks and looks down the aisle probably pointed to a special position of the sun, moon or some bright star.

The three lanes left uneroded point westward. At the summer solstice, the longest day of the year, the sun sets directly in the centre of one of the aisles. At the winter solstice, the shortest day of the year, the sun sets in the other still-intact aisle. A third aisle points at the north star, Mr. Haag said.

Mr. Haag believes that the monument was used by people of the area ­ at the time about 5,000 occupied the village at the site ­ to mark the key times of the year for hunting and gathering food.

David Thomas of the American Museum of Natural History said that some scholars, although impressed by the size and pattern of the monument, are doubtful that this and other ancient monuments were used at astronomical calendars.

The positioning of the monuments might well be accidental in some cases, he said. He pointed out as an example that in St. Louis, looking through the Gateway Arch to the city, one can see that some monuments and the street pattern of the entire downtown area are all aligned on an east-west axis. If someone were to dig the city up a few millennia from now, the city might appear to be laid out as some astronomical setup. Mr. Haag replies that the probabilities of more than one arm of the monument coinciding exactly with key points in the solar year is very small. No major features of St. Louis or any other place makes a pattern corresponding to astronomical points in that way, he said.

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Boyne Valley Tours Pick up and return to your accommodation or cruise ship. Suggested day tour: Newgrange World Heritage site, 10th century High Crosses at Monasterboice, Hill of Tara the seat of the High Kings of Ireland and the Hill of Slane where St. Patrick let a Paschal fire in 433  More ...