How the Ancients measured the Earth (Megalithic)

[Keimpe]

[Mick Harper]

My original contribution to this debate (I think, I am never quite sure) was to take Keimpe/Hatty's idea of a long straight horizontal edge (eg Waddon Hill, but the whole 'bowl' of Salisbury Plain would do it better) and say that 'simultaneity-of-observation' can be achieved in two ways -- by shining bronzed surfaces or making loud noises -- and having things relayed as necessary. It is known that various 'mysterious megalithic constructions' produce loud and distinctive noises in certain circumstances.

Once you've got the time lag between the sun touching a point there and again there (on an east-west line) then you can...um... compute the speed of the turning earth or whatever. And by measuring the angle when the two points are north and south, you get the circumference of the earth. Probably. I'll leave Brian to work out the details.

However, and not just because it is definitely mine own, I still prefer measuring the angle between rising and setting sun at the two ends of the Michael Line. It is reasonably straightforward measuring how far north Norfolk is from Cornwall since points-of-equal-latitude can surely be computed easily enough so you would be doing an Aswan-to-Alexandria calculation as soon as you got a place in Wales parallel to Norfolk and due north of Cornwall. However this is tricky in practice since you can't walk due north from Cornwall to Wales, as you can from Aswan to Alex,.hence the importance of Avebury, halfway along the line from where you do do the actual calculations.

In fact, now I come to think of it, if Avebury is halfway in distance, it will also be halfway in latitude between the two ends of the Michael Line and so direct calculations can be made at Avebury for all kinds of things, knowing that they represent the situation at Cornwall and Norfolk. Working out the halfway point on the Michael Line is only a matter of time and resources thrown at the problem, it is not difficult technically.

[Keimpe]

[Keimpe]

[Mick Harper]

Surely it is not necessary. Once you have a stone circle to squint along you just note where the sun is going down at the point where you last see it -- it goes practically (ie at this level of accuracy) straight down from there, does it not?

However your point raises a more interesting one. By utilising the Michael Line, on a known day of the year, it is possible to get a wondrously accurate squint at the sun's exact rising point (at Norfolk) and also its setting point (at Cornwall). With a known angular distance between Norfolk and Cornwall, known halfway point at Avebury etc, this should give you access to all sorts.

[Hatty]

[Keimpe]

Is there a village or city in Norfolk on which it's agreed upon nowadays that the St. Michael Line ends (or rather begins) there?

[Mick Harper]

From previous correspondence, wasn't it the current Norfolk/ Suffolk boundary or something similarly significant?

[Keimpe]

I don't know. All I need is a name that Google Maps recognizes. So far I've had to sort of guess what the end point should be. I'd rather have a more fixed village/city/whatever.

[Hatty]

The official endpoint is Hopton-on-Sea.

Bromholm might be worth investigating. The Priory which was owned by Cluniac monks was the centre of a thriving pilgrimage industry due to its relic of the Holy Cross known as the Holy Rood of Bromholm(e). Holm is said to mean 'rising land' or island in OE. (And talking of 'broom' why was it considered unlucky in May in Wiltshire, Sussex and Suffolk? Domesticity was a distraction from the serious business of angle-measuring?)

[Keimpe]

[Keimpe]

Let's wrap things up:

It's amazing how things suddenly seem to fall into place, once you've looked at things from a new perspective. I guess some of our members have had this more than once. For me it was a first, and I loved every second of it.

After I got home I started wondering how Silbury Hill could have been used to measure the earth. First of all, you probably want to measure in a North-South direction, since then you get the polar circumference. Because, even if you would be able to measure earth's circumference as an extension of the St. Michael Line, it would be a rather meaningless circumference. There's only two that matter: the equatorial and the polar. Not some odd diagonal one.

So, would there be a place north of the Avebury complex with a May 1 sunrise moment that exactly coincides with the Silbury Hill sunrise? So you can measure the difference in the angle towards the sun? And would the distance between that point and Silbury Hill be measurable?

And then it hit me. Hadn't I been there myself only days ago? Walking the Ridgeway, 100(s) of yards above the plains? Extending to the north as far as the eye can see? I even took pictures:



There's no need of a second observatory with the same Silbury characteristics. All you need is one fixed moment in time and a means to relay that moment to another phsysical location, as fast as possible, preferrably instantaneous.

So how about using the speed of light? Maybe King Sil's legend about his shining armour wasn't about some buried King, maybe it was about how Silbury Hill was used! A mirror (or some shining bronze plate - after all, we're talking bronze age here) could have been placed on top of Silbury Hill in the direction of the top of the Ridgeway (only a few miles away), from where it could be deflected in the direction of the plains as far as the eye can see!

Then you measure the angle towards the sun from your most distant point, after which you measure your distance to the Ridgeway over fairly even terrain, and you're in business.

When I started to investigate a possible Ridgeway - Silbury Hill connection, I stumbled accross another marvellous coincidence: it seems that when walking from the Ridgeway towards Avebury, during the last couple of miles, Silbury hill seems to pop in and out of view over Waden Hill with every step you take.

Someone even gave it a name: The Silbury Game. How wonderfully naive ... here's more information:

http://www.themodernantiquarian.com/site/4757

Ofcourse, this triple alignment of Silbury Hill + Waden Hill + The Ridgeway is most likely a tool for very accurately measuring the sun at a certain position/moment. Very much like looking through the barrel of a gun.

So that's my theory: the polar circumference of the earth was measured several thousand years B.C. on one particular May 1st, shortly after sunrise, by deflecting the sunlight hitting Silbury Hill back towards the Ridgeway and then in a nothern direction. As far away as possible the angle towards the sun was measured, then the distance towards the Ridgeway was measured and from this the polar circumference could be calculated.

I'm sure there's more to it than this. I hope it's just the beginning of much more. Surely, Silbury Hill has more tricks on its sleeve. Maybe West Kennett Longbarrow is involved (it's in direct view of Silbury Hill), and maybe even Milk Hill and Tan Hill. Who knows. There's an awful lot to explore.

[Hatty]

I completely agree that there is a relationship between the Ridgeway at Overton Hill and Avebury at Silbury Hill. The fact that Silbury cannot be seen until you get to the end of the Ridgeway is surely deliberate. The Ridgeway predates Avebury of course, its original function was presumably what it does best, trace the easiest though not straightest route to the Goring Gap.

When you look at the horizon from within the Avebury complex it appears bowl-shaped but level. (Looking at a similar site albeit on a smaller scale, a Bronze Age enclosure in Dorset, I immediately thought "it can't be natural, it's too perfect a bowl" but was told by a stone expert that it's a 'sink hole'.)

Would not someone signalling from Overton Hill be in full view of Silbury's 'twin', the Marlborough Mound, also? The Mound is on the same latitude as Silbury. (The Normans built a keep on it, apparently the college swimming pool follows the line of the castle moat). The two sites are not intervisible but they are linked by the Kennet river; sound travels over water.

On an earlier Ridgeway walk I went past Temple Farm, formerly part of a Templar estate, which overlooks a valley and thought "what a fabulous view that house has". I now realise it is due south of Barbury Castle up on the Ridgeway and the "fabulous view" is north/north-east facing. It might have been on a north-south alignment. Makes you suspect it's one coincidence too many.

Silbury Hill was constructed at the same time as the pyramids, part of a wider phase of measurement, great minds everywhere trying to find a solution to a conundrum that's on the intellectual agenda, like calculus or evolution later?

[Keimpe]

[Mick Harper]

Welcome to the "I know something nobody else in the world knows" Club, Keimpe. Just one minor point