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Stonehenge is one of those iconic monuments that has captured the imaginations of people. Its alignment with the Sun at the solstices is as clear as day, although the function of the monument remains uncertain. But researchers will be spending the next several months looking at a different type of alignment – some stones might be aligned to the lunar standstill.
Things do not stay still in the sky. Due to the inclination of the planet with respect to its orbit, the position of the Sun and where it rises and sets moves about over the course of the year. Stonehenge is aligned in such a way that the light of the sunrise on the summer solstice and the last rays of sunset on the winter solstice go through the middle.
But beyond the stone circle, there are the so-called station stones whose function is unknown. They appear to be connected not with the Sun, but with the Moon. Similar to the solar movements, the position of moonrise and moonset changes due to the inclination of the Moon’s orbit with respect to the Earth. But it is not an annual thing. It takes 18.6 years for the cycle to complete.
During the peak of its cycle, the Moon’s declination swings from 28.725 degrees north to 28.725 degrees south in a single month. This period is known as the major lunar standstill (lunistice) and the next one will go on until January 2025. So researchers will be visiting Stonehenge several times over the coming months, all the way through the major standstill, to understand the potential alignment between the monument and our natural satellite.
“I think the moon in general would have been very important to them,” Heather Sebire, senior property curator of Stonehenge, told IFLScience. “And you know when they had a full moon, perhaps they had extra light and they were able to do things that they couldn’t do the rest of the time”
“In terms of the lunar standstill, they think it might have significance here because of there are four outlying stones known as the ‘station stones’. Only two of them survive and they form a rectangle, and there is some thought that might have something to do with the setting outside of the circle.”
In a minor lunar standstill, the declination of the Moon is between 18.134° (north or south). The next one is happening in 2034.
As researchers continue to investigate this fascinating alignment, Stonehenge is inviting people to join in the fun. As is traditional, visitors will be allowed into the circle for the solstice (which this year is the earliest since 1796), but the following day it will be all about the lunistice.
https://www.youtube.com/watch?v=nZHaqSf8VxM
The lunar standstill moonrise event is online only, so you can watch the livestream from the comfort of your own home, wondering together with the researchers if this great monument was also aligned with the Moon.