In relation to its connection to the sky, Stonehenge is greatest identified for its photo voltaic alignments. Each midsummer’s night time tens of 1000’s of individuals collect at Stonehenge to have a good time and witness the rising Solar in alignment with the Heel stone standing exterior of the circle. Six months later a smaller crowd congregates across the Heel stone to witness the midwinter Solar setting inside the stone circle.
However a speculation has been round for 60 years that a part of Stonehenge additionally aligns with moonrise and moonset at what is named a significant lunar standstill. Though a correlation between the format of sure stones and the most important lunar standstill has been identified about for a number of many years, nobody has systematically noticed and recorded the phenomenon at Stonehenge.
That is what we’re aiming to do in a mission bringing collectively archaeologists, astronomers and photographers from English Heritage, Oxford, Leicester and Bournemouth universities in addition to the Royal Astronomical Society.
There may be now an abundance of archaeological proof that signifies the photo voltaic alignment was a part of the architectural design of Stonehenge. Round 2500 BC, the individuals who put up the big stones and dug an avenue into the chalk appeared to wish to cement the solstice axis into the structure of Stonehenge.
Archaeological proof from close by Durrington Partitions, the place the place scientists imagine the traditional individuals who visited Stonehenge stayed, signifies that of the 2 solstices it was the midwinter one which drew the most important crowd.
However Stonehenge consists of different components, equivalent to 56 pits organized in a circle, an earthwork financial institution and ditch, and different smaller options such because the 4 station stones. These are 4 sarsen stones, a type of silicified sandstone frequent in Wiltshire, that have been fastidiously positioned to type an nearly precise rectangle encompassing the stone circle.
Solely two of those stones are nonetheless there, and so they pale compared to their bigger counterparts as they’re just a few toes excessive. So what might their function be?
Drone Explorer/Shutterstock
Lunar standstill
The rectangle that they type isn’t just any rectangle. The shorter sides are parallel to the primary axis of the stone circle and this can be a clue as to their function. The longer sides of the rectangle skirt the skin of the stone circle.
It’s these longer sides which are thought to align with the most important lunar standstill. For those who marked the place of moonrise (or set) over the course of a month you’ll see that it strikes between two factors on the horizon. These southern and northern limits of moonrise (or set) change on a cycle of 18.6 years between a minimal and a most vary – the so-called minor and main lunar standstills, respectively.
The key lunar standstill is a interval of about one and a half to 2 years when the northernmost and southernmost moonrises (or units) are furthest aside. When this occurs the Moon rises (and units) exterior the vary of sunrises and units, which can have imbued this celestial phenomenon with that means and significance.
Fabio Silva, CC BY-NC
The strongest proof we have now for folks marking the most important lunar standstill comes from the US southwest. The Nice Home of Chimney Rock, a multi-level advanced constructed by the ancestral Pueblo folks within the San Juan Nationwide Forest, Colorado, greater than 1,000 years in the past.
It lies on a ridge that ends at a pure formation of dual rock pillars – an space that has cultural significance to greater than 26 native American tribal nations. From the vantage level of the Nice Home, the Solar won’t ever rise within the hole between the pillars.
Nonetheless, throughout a significant standstill the Moon does rise between them in awe-inspiring vogue. Excavations unearthed preserved wooden that meant researchers might date to the 12 months episodes of building of the Nice Home.
Of six chopping dates, 4 correspond to main lunar standstill years between the years AD1018 and AD1093, indicating that the location was renewed, maintained or expanded on consecutive main standstills.
Returning to southern England, archaeologists assume there’s a connection between the most important lunar standstill and the earliest building section of Stonehenge (3000-2500 BC), earlier than the sarsen stones have been introduced in.
A number of units of cremated human stays from this section of building have been discovered within the southeastern a part of the monument within the basic route of the southernmost main standstill moonrise, the place three timber posts have been additionally set into the financial institution. It’s attainable that there was an early connection between the location of Stonehenge and the Moon, which was later emphasised when the station stone rectangle was constructed.
The key lunar standstill speculation, nonetheless, raises extra questions than it solutions. We don’t know if the lunar alignments of the station stones have been symbolic or whether or not folks have been meant to watch the Moon by way of them. Neither do we all know which phases of the Moon can be extra dramatic to witness.
A seek for solutions
In our upcoming work, we might be attempting to reply the questions the most important lunar standstill speculation raises. It’s unclear whether or not the Moon would have been robust sufficient to forged shadows and the way they’d have interacted with the opposite stones. We may even must examine whether or not the alignments can nonetheless be seen right now or if they’re blocked by woods, visitors and different options.
The Moon will align with the station stone rectangle twice a month from
about February 2024 to November 2025, giving us loads of alternatives
to watch this phenomenon in several seasons and phases of the Moon.
To deliver our analysis to life, English Heritage will livestream the southernmost Moonrise in June 2024, and host a collection of occasions all year long, together with talks, a pop-up planetarium, stargazing and storytelling classes.
Throughout the Atlantic, our companions on the US Forest Service are creating instructional supplies in regards to the main lunar standstill at Chimney Rock Nationwide Monument. This collaboration will lead to occasions showcasing and debating the lunar alignments at each Stonehenge and at Chimney Rock.
