Neinast: How the Newark Earthworks connects to the moon

Most readers know that the Octagon earthworks in Newark are somehow related to the Moon. But how are they related and what did the ancient mound builders know about the moon?

Ancient peoples would have noticed the movements of the sun and the moon and the progression of the seasons. Each day as summer approached, the eastern rise point of the Sun moved north. It then hovered around the same place (which we call the solstice northern maximum) for about a month before heading south again. It continued heading south into the winter, hovered at what we call the solstice southern maximum, and then headed north again. They also would have noticed that in the summertime, the Sun stays in the sky for a long time each day, but in the wintertime, it lingers but a short while.

While watching the Sun, those peoples also would have noticed the Moon and its phases, which are obvious and flashy and repeat themselves about every 29½ days.

They must have noticed another major motion to the Moon, the time it takes to orbit the Earth, that is not so evident. With a cycle of about 27⅓ days, the Moon emulates the Sun!

Each day, as the Moon rises in the east, the rise point moves north. It sits near the most northerly point for a couple of days, and then moves south again to the most southerly point, hovers there a bit, and then heads back north.

In the mid-1700s, French astronomers called these lunistices ("lunar stasis"). They further distinguished them as boreal lunistices (boreal meaning north, as in the aurora borealis) and austral lunistices (austral meaning south, as in Australia).

Just as with the summer (northern) solstice, the Moon stays in the sky for a long time for the boreal (northern) lunistice, but lingers a short time for the winter/austral (southern).

During the lunistices, the lunar rise points are rather close to the solar rise points for the soltices. But not quite.

The Moon's orbit around the Earth is tilted about 5.1° compared to the earth's orbit around the Sun. That extra tilt affects the northernmost and southernmost rise points of the moon during the lunistice "seasons", and it is that variation that the Octagon captures.

Furthermore, that tilt in the Moon's orbit sometimes adds to the northern- and southernmost rise points, and sometimes subtracts. As it does so over an 18.6 year period, the effect is to strengthen or weaken the degree of the Earth's natural tilt as far at the Moon is concerned.

Right now we are heading to the time when the effect is strengthened and the Moon's risepoints are headed to a maximum, which is called a Major Standstill. That will occur in 2024-2025. But even now, two years off, the Moon is working its way towards aligning with the Octagon at each lunistice, and it is getting pretty close.

The next Open House at the Octagon is on October 16, and it just so happens that it coincides with a boreal lunistice. The northernmost moonrise will occur at around 10:30pm the night before, on the 15th. And the moonset will happen during the day of the 16th at around 2:30pm. The Moon will be about 4 moon-widths away from a full alignment.

Robert Neinast, with his degrees in physics, got interested in the details of the Newark Earthworks when he participated in the week-long pilgrimage from the Chillicothe Earthworks to the Newark Earthworks in 2009.