The Equinox at Loughcrew Cairns

Loughcrew Cairn TRising above the fields and pastures of County Meath near the town of Old Castle stand some of the most impressive megalithic structures in Ireland. Some 24 rocky mounds dot the tops of the highest hills of the Slieve-na-Calliagh range. The largest of these were described in the 19th Century as passage tombs, but it is now clear that they served a far more interesting purpose, as astronomical clocks.

Passage Tomb at Loughcrew CairnsSome 5,000 years ago, the stone age people living in this place went to great effort to construct monuments that track the apparent motion of the sun as it rises and sets. They carried bright white quartz from a distance to face the monuments, which must have stood out as beacons to the surrounding countryside on a moonlit night.

There are hints that the society which created these mounds was matriarchal. One of the mounds features what appears to be an enormous stone chair, and local legends refer to it as the “Hag’s Chair” or the “Witch’s Seat.” The form of the passages themselves is suggestive of a fertility cult, as are some of the mysterious carvings that are found at the back of the passages.

Carvings at Loughcrew Cairns

The passage at Cairn T is perfectly aligned with the rising sun on the equinox. At dawn today, a beam of light will trace a path across these carvings, illuminating the four sun symbols in order diagonally from top left to bottom right.

I visited this site a few years ago and found it quite moving. Being off the beaten track, we were able to take in the ruins without jostling crowds of tourists. My wife’s family hails from Old Castle, so it is not inconceivable that some of her ancestors were involved with the creation of these monuments. The experience of crouching in those passages is intimate, a shared experience across millennia. This intimacy is nicely balanced with the grandeur of the views that the site affords.

The connection I felt with the site is a deeply human one. It seems that every human culture has tracked the solstices and equinoxes, from the wood henges at Cahokia Mounds to the famous Stonehenge in England. While many of their secrets are lost to history, in one respect these technologies still function, as they mark off time in beams of sunlight on stone.

The people who built these structures did not how the sun burns or why the moon waxes and wanes. They did not know why five stars wander while the rest remain fixed. At Loughcrew, they did not know that the line of their four carved suns matches the tilt of the earth’s axis. But they could see with their naked eyes that the cosmos follows regular patterns, and they could know these patterns with the tools at hand, as we do today.