The beam of sunlight on the floor of the chamber at Newgrange

91 On the Winter Solstice, the light of the rising sun enters the roofbox at Newgrange and penetrates the passage, shining onto the floor of the inner chamber. The sunbeam illuminates the chamber of Newgrange for just 17 minutes.

92 It is believed by some researchers that the colour of the sunrise on the morning of Winter Solstice was the original inspiration for the name of the hill over which that sunrise occurs when viewed from Newgrange. The hill is called Red Mountain.

93 It has been suggested by Robert Lomas and Christopher Knight that Venus would have been visible inside the chamber of Newgrange at certain times during its eight-year cycle.

94 It is an astronomical fact that at certain times during its 19-year cycle, the Moon shares the same declination, and therefore the same rising azimuth, as the midwinter sunrise. Therefore, there are times during the Moon's cycle when it too would be visible inside Newgrange.

95 Newgrange and Dowth are situated such that at moonrise at the time of minor standstill north, the Moon comes up over Dowth viewed from Newgrange. At minor standstill south, the Moon sets over Newgrange viewed from Dowth. Martin Brennan suggests a similar minor standstill orientation for Newgrange and Knowth.

96 A survey of the roofbox, passage and chamber of Newgrange by Dr. Jon Patrick in 1972 found that the Winter Solstice orientation of the site was an original feature, and that they were sophisticated constructions, intended to maximize the accuracy and length of the beam entering the chamber.

97 A further study by Tim O'Brien showed that at the time of construction the sun-beam was so accurately framed by the roof-box aperture that Newgrange could be used to determine the exact day of solstice.

98 While sunrise on Winter Solstice takes place over a hill across the Boyne river called "Red Mountain", sunset takes place over a hill in the distance called Realtoge, which means "star" or "young star" and which has a large ringfort on its summit.

Is Newgrange the "womb of the Moon"?

99 Newgrange is known as a brugh (or brú), which is often translated as meaning a "mansion". However, there is an old Irish word - Brú - which means "womb". Could Brú na Bóinne mean "womb of the bright cow" or "womb of the Moon"? Many researchers have pointed out the layout of the entrance, passage and chamber of Newgrange has a resemblance to the female reproductive organs.

100 Frank Prendergast's research demonstrated how the shadow of GC1, the megalith adjacent to the entrance, would have crossed the lower part of the three spirals on the west side of K1 at the winter solstice; that the shadow of GC-1 would have crossed through the centre of the three spirals at the period when the south declination of the sun was half its annual maximum; that the shadow of stone GC-2 similarly crosses the same three spirals at the equinox. Click here for more.