The 2018 autumn equinox is on Saturday, 22nd September for those of us in the Northern Hemisphere. On this day, the sun rises at due east, passes directly above the equator, and sets in due west.
This divides the day into two equal halves of light and dark, but due to the way light passes throughthe Earth’s atmosphere, we won’t have exactly 12 hours of light and exactly 12 hours of dark.
Today, we know and understand how the atmosphere refracts light. We have satellites out there photographing the Earth and other planets from space. But how did our most ancient ancestors understand this? We know they did because they left elaborate monuments based on the movement of the sun, such as Newgrange and Loughcrew.
In September, Loughcrew takes centerstage. Less famous than Newgrange, it is just as amazing and significant. High on a hilltop with a commanding view of the surrounding counties, Loughcrew is a stone cairn. During the summer, a guide welcomes visitors and ensures the small cavern with the amazing carvings is not too crowded. But visitors can enter freely and see the carvings up close with no pressure to hurry through. It’s small and dark, but a flashlight can reveal all. The interior is decorated with stylized circular carvings. Are they flowers? The sun? A wheel representing time? We simply don’t know for sure. But our ancestors designed Loughcrew so that the sun illuminates the interior at the equinox.
How Did Pre-Christian Ireland Track Time?
We can visit these places, walk-in our ancestors’ footsteps and see first-hand the incredible carvings they made. But deciphering them is another story. We can study astronomy and use our observations of the sun’s movements to learn the science of it. But humans are more mysterious. We just don’t have enough clues to say for certain what the intricate carvings at Loughcrew mean. But the very existence of the place, an elaborate collection of cairns atop a hill designed around the sun’s movements, tells us our ancestors were very aware of the cycles of the year.
It begs the question of how did they track time? It’s obvious how anyone at any time or place would measure a day… but how did they divide the year? They knew about the sun’s movements and clearly celebrated solstice and equinox in some way. Did they have months? Did the notion of a week mean anything to them?
Some evidence suggests they did indeed have a calendar. One of the kerbstones at Knowth, at the Boyne Valley in the same complex as Newgrange, is known as the Calendar Stone. Featuring an elongated oval carved with a wavy line and several circular carvings, some experts believe it shows the year divided into cycles of the moon. That’s a fairly complex concept, considering that it doesn’t divide equally. (That’s why we have a leap year.) Another kerbstone at Knowth is called the Lunar Stone because it appears to depict the phases of the moon during one lunar cycle.
Today, Ireland is known for being fairly laid back about time keeping. But we have ample evidence our ancestors were very aware of time!