Above the entrance passage is a square hole on the roof, which precisely aligns with the rising sun at the winter solstice of on December 21st, so that the rays touch the ground at the very center of the tomb for about 20 minutes. .
Some have asked whether the entry of the sun's rays into Newgrange at winter solstice could be a mere accident, resulting from a chance alignment, or worse still, from an unwitting alteration of the entrance during reconstruction. Professor Michael J O'Kelly was in charge of excavations at Newgrange and he took the precaution of double-checking, and asked a surveyor, John Patrick, to investigate the phenomenon. In an article published in 1974, Patrick concluded that the orientation of Newgrange must have been arranged deliberately by its builders; the sun had shone down the passage to the inner chamber ever since its construction some 5,000 years ago, and that it would continue to do so indefinitely (Patrick 1974: 517-19). Unfortunately, there is still unwillingness on the part of many archaeologists, and possibly inability, to consider adequately astronomical interpretations of passage mound engravings. A further puzzling tendency is the insistence that these mounds were primarily designed as tombs, despite the admitted absence of clear evidence for large-scale burial. Although it is not completely clear as to the exact nature of these megalithic monuments, there is a good deal of evidence that they were deeply ritual in purpose, not only in worship and astronomy but also in burial.
Ogham served as an alphabet for one of the ancient Celtic languages of Ireland. There is still a lot of debate over the origins of Ogham even though most of the findings have been translated. Ogham was used in fifth-century Ireland and is a 25 letter alphabet that was supposedly inspired by Ogma, god of eloquence. Ogham was carved on stone and wood and read from the bottom to the top.
