RASC eNews

"Newgrange is an extremely well-preserved and very large neolithic monument dating from about 5000 years ago, dated from both the archaeological and astronomical evidence. A corballed inner chamber within the mound ... lies at the end of an 18m downwards sloping tunnel. On each winter solstice for the past 5000 years the first rays of the rising Sun would have passed through a specially constructed aperture ... above the entrance. Today these rays fall on the floor of the inner chamber ... but 5000 years ago the actual stone would have been illuminated. Newgrange is the oldest neolithic monument in the World with a known astronomical function, and it predates the better-known Stonehenge in the neighbouring island of Great Britain by more than a thousand years.

... At some unknown time in the past the passage was blocked and the  function of the observatory lost - although, strangely, local folklore tells of the midwinter sunrise entering the mound. It was rediscovered when the mound was excavated in the 1960s and since that time a small number of observers have been in the chamber each year to observe the event. I was there a few years ago and it is [a] very moving experience - one can not help but think of our remote ancestors ... doing the same thing."

Professor Michael Redfern
School of Physics, National University of Ireland, Galway
International Year of Astronomy 2009, Irish Node