Today (if you happen to be in New York and it is 28th May or 16th July 2013 when you read this) it will be possible to experience the ultimate urban prehistory phenomenon, Manhattanhenge, when the metropolis becomes a megalithic monument and skyscrapers and streets mediate an encounter with the setting sun, a kind of pagan solar power.

Manhattanhenge is the name for an event that occurs twice a year on lopsided solstices – when the sun sets in alignment with the east-west element of the grid street plan of Manhattan. On such occasions, if one stands in eastern Manhattan, and look west across clear thoroughfares such as 14th, 23rd, 42nd or 57th Street the skyscrapers frame a view of the full or partial sun setting at the end of these streets. This effect has become increasingly popular as a spectator event in recent years, with crowds drawn to prominent viewing positions. (For this year’s times and viewing positions, see the Hayden Planetorium website).

I first came across this phenomenon via the TV show CSI New York in an episode from the sixth season entitled, believe it or not, ‘Manhattanhenge’. In this particular episode of the forensic procedural drama, there is a lot of excitement, underpinned by implausible detective work and a lot of running about. The CSI Files takes up the story:

‘Hawkes finds two faded tickets and begins to analyze them. Hawkes is able to put it all together: Eckhart was using the sun tracking equipment to pinpoint Manhattanhenge: the day when the sun rises [sic] in line with the city’s grid. Manhattanhenge is scheduled to take place on December 5th: Hollis Eckhart’s birthday….’

For the purposes of this storyline, we need not worry ourselves who Hawkes might be, or Eckhart, but clearly Manhattanhenge is a vital element in the episode. The bad guy could have saved himself some time, however, by checking out the date and time of the next Manhattanhenge event online, rather than using fancy ‘sun tracking equipment’. (And what does that mean – eyes?)

The story quickly reaches an exciting conclusion:

‘Eckhart runs when he sees Mac, and the CSI gives chase, eventually cornering him in a Manhattan intersection as the sun rises. Eckhart, seeing the ghost of his wife, raises his gun to his head, but Mac manages to talk him down and the killer surrenders.’

All very easy in the end for this Mac character, and a ghost seems to have become involved as well. Although the programme did suggest Manhattanhenge happened at sunrise, not sunset, this skyscraper solstice has clearly become part of pop culture, and cultural consciousness. And this can’t be said for the vast majority of urban prehistory.

In 2010, I took part in an Inspace event in Edinburgh entitled Here comes the sun. I was asked to speak about the significance of the sun to people in prehistory, and in particular how archaeologists make sense of this. One of the other panellists was a retired NASA astronaut, who had a series of badges sewn onto his blue jumpsuit reflecting how many days he had spent in space.

Here are some of the more interesting slides from my presentation:

The main thrust of my talk was that the sun had always been important to people, although archaeologists have long been unsure about how this manifested itself. We know that it must have been important, and used in a number of ways such as:

Defining the agricultural cycle and seasons

Calendar, helping mark certain events in the year

Aid to way finding during journeys (by sea and land)

Rudimentary guide for telling the time

Suntanning

The sun would have been a means of organising the world – both spatially and temporally. But given that we are dealing with people who had no ‘scientific’ understanding of the nature of the sun, nor indeed of the earth, then we can only speculate how they explained its presence and movement, its coming and going over the horizon line. What did they think of the small orange disk that moved across the sky? How did they explain where it went at night, or why its heat declined and returned? And given this level of knowledge, whether the sun would come back or regain its warmth was always an act of faith, and hope. What would they do if the sun died?

The urban grid that is Manhattan allows one modern (pagan) attachment to the sun to continue to be celebrated. But the streetscape of Manhattan was not laid out with any concern for the movement of the sun. The famous grid street system, with numbered avenues, was first developed in the early 19th century, the result of the Commissioners’ Plan of 1811 (an 1807 version of this is shown above). It originally consisted of 12 north-south avenues, and 155 cross streets, running east to west. The width of most of these avenues and the distances that they were spaced from each another was standardized. This grid, to establish order and healthy conditions to Manhattan, was the outcome of a pragmatic decision related to simplicity and cost-effectiveness.

In other words, Manhattanhenge is an unintended consequence.

This is troubling. What if the solar and lunar alignments that are commonly attributed to stone circles, stone rows, henges, cursus monuments and standing stones are unintended consequences, coincidences that were only noticed after the event, mostly by middle-aged men with theodolites and IBM computers?

The unintended consequences argument that applies to the Manhattan grid is not one that would be accepted by ‘archaeoastronomers’ (as Alexander Thom and others are sometimes known). Instead, they believe that people in prehistory had a pseudo-scientific interest in heavenly bodies. The result of this belief was the development of the argument that prehistoric people were able – through experience and decades of observation – to record and predict the movement of the sun, moon and some key constellations. In some cases, it has been suggested that they could even predict eclipses.

According to this 20th century scientific mind-set, the response prehistoric people had to the sun was to study it, and to build monuments to the golden globe in the sky. People in the Neolithic and Bronze Age did not understand the true nature of the sun, but they recognised the cyclical nature of its movement, its predictability. And so ‘priests’, ‘shaman’, the ruling intellectual elite, were able to reflect the glory of the sun, controlling the sun by making it come back in predictable ways, and this elite organised ever more extravagant building projects to make sure everyone else in society knew how important they were.

The means by which these astronomer-priests were able to exert control was through secret, arcane knowledge, encapsulated in stage-managing experiences, predicting the future and facilitating the return of the sun and moon day after day, season after season, year after year, generation after generation. Careful observation of the sky, and the erection of timber posts and standing stones, allowed these experiences to be opened up – and demonstrated – to whole communities.

Archaeoastronomers study and characterise such astronomical wizardry through the use of calculations, equations, geometry, trigonometry, diagrams, arithmetic, algebra, statistics, astronomy and mathematics.

The absolutely obsessive levels of recording of the movement of bodies in the sky required to build stone observatories in the Bronze Age is only matched by the absolutely obsessive levels of recording of these stone observatories by archaeoastronomers.

Gerald Hawkins used an IBM computer to prove Stonehenge was a stone computer. Alexander Thom called the stone rows of Caithness in northern Scotland ‘machines’ and ‘devices’ because to his mind the intellect of Bronze Age people was best expressed in 20th century terms: through science and engineering. Thom’s views are expressed brilliantly in this BBC Chronicle episode from 1970 about his theories, called Cracking the Stone Age Code.

But: what if the solar and lunar alignments that are commonly attributed to stone circles, stone rows and standing stones are unintended consequences that we read into them? Are we in danger of reflecting back onto the ancient past our own interests, concerns, standards and knowledge? What if the astronomical events and phenomena that are so carefully searched for at megalithic monuments across the world are actually simply unintended consequences of complex stone structures that were built for any number of other reasons, and just happened to be beneath a variable, dynamic and complex sky? What would we do if we were unable to explain something in our own terms? What would we do if the sun died?

It is human nature, I think, to seek order in chaos, to see patterns in everything, and to seek to make sense of the mysterious and unknown. (All reasons of course why megalithic monuments may have been built in the first place.) And by chance, there is currently an exhibition of works entitled ‘Human Nature’ by the artist Ugo Rondinone at the Rockefeller Centre Plaza in New York (until 7th June). (This event is sponsored by feeble coffee.)

The focus of the exhibition is nine giant stone figures. The Public Art Fund website for the project explains:

‘Using rough-hewn slabs of bluestone from a quarry in Northern Pennsylvania, the artist has imbued each figure with a distinctive personality. Like a forest of giants, their immovable legs form gateways through which visitors may pass, sensing the tactile surfaces of these primal forms.’

And of course this is significant, because these stone figures mimic the trilithons of Stonehenge, and ‘bluestones’ were a component of the original Stonehenge (although the trilithons were made from more locally sourced sarsen). This artwork has encouraged many to suggest that this is an urban vision of Stonehenge (one blogger wrote: ‘When the sun is high, they cast almost mystical shadows across their 6,700-square-foot poured concrete base’, and of course, most of the big stones at Stonehenge are held in place by concrete). Others have suggested they are more reminiscent of the Inuksuit sculptures of the Inuit, simple piles of stones arranged in rough human forms in the Arctic. These bizarre statues have in the past been used for helping with navigation and hunting, rather like the sun was used by prehistoric people.

The nine bluestone figurines have become entangled in a series of anthropomorphic analogies, and the same could also be said of Stonehenge trilithons with their vaguely leg-and-torso form. Perhaps, though, this is just another layer of unintended consequence, and this is what happens when we are invited to make sense of megaliths, sculpture and even cityscapes. In distinctively different ways, Stonehenge and New York continue to inspire wonder, awe and inspiration. The creative and emotional responses they promote cannot be boiled down to equations and formula, and so crowds will continue to gather in Manhattan and Salisbury Plain to watch the sun and architecture interact in magical ways, whether unintended consequence or not.

Sources: Much of the basic information about Manhattanhenge comes from the Hayden Planetorium website (link above), the source also of the mocked up sunset photo. The CSI episode information came from the CSI files webpage, and the two screengrabs from the Manhattanhenge episode also come from this source. The Manhattan street plan from 1807 is an open source image from Wikipedia; the Thom picture is available in various places online, the Hawkins image was sourced from a blog about Stonehenge and the weird book cover is available widely. The source for the Human Nature photo from the NY Timeout website. The Inuksuit postcard came from Judith Burch’s webpage. Jan took the photo of Manhattan from above, Adrian told me about ‘ugohenge’, and Jimmy suggested I blog on this topic – thanks to all of them. The title of this blog is adapted from song by The Flock.