Support post position becoming interesting. Apparently there is a singular huge pit at the centre of Stonehenge.
Will research for next edition of "A Neolithic Universe" (there are about 48 similar items queued for adding as additional evidence).
brian-mountainman.blogspot.com/2025/03/extr...
[2/2]

It's easy to estimate how far they are from each other and then it's also easy to estimate how far down the horizon is when looking from Feddau to Eryr. From that, you can estimate that the world, if a disk, would be very small. From that, you know it must be a sphere. [5]

But there are other ways to find out that you're on a sphere. A really special place for that is the end of the Preseli range: two peaks (Feddau and Eryr) are at the same level and each is above horizon when viewed from the other [4]

But at high level, you would be able to look down at the boat. So to tell that it's a sphere, you might have to be simultaneously at high level and at low level (or really fast at scaling down a mountain). So if your boats aren't big, it'd be hard to make a judgement one way or the other. [3]

If the earth were a flat disk, then it depends heavily on how high up you are and how big the ships are. But for all intents and purposes, the arrival of a small boat on a flat disk looks much the same as the arrival on a spherical sea (one metre high waves close to you will obscure the boat) [2]

Really interesting question. The eye can only distinguish objects at about 1/5000 slope (ie about 0.5 minutes). So a 4m high sail of a ship might, for someone with superb eyesight, a very clear day, and a bright florescent sail, be visible at about 20km. [1]

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Interesting list. This project (@aneolithicuniverse) is well researched. But the history bit depends on POV.

[5] This explanation is far more likely than any other current theory. Presented at various archaeological conferences, the hypothesis also contains little or nothing in the way of controversy (so is not well known).

This 'gentle reminder' thread inspired by the post below.
bsky.app/profile/greg...

[4] The original version (2012) can still be found on the Megalithic Portal (run by @megalithic.bsky.social). Most of the text has changed little from that initial edition to the (much expanded) version which now forms the 3rd edition.

www.megalithic.co.uk/download.php...

[3] The hypothesis is all about knowledge, so has no unfalsifiable standard narratives (such as religion, politics or unification).
In 2020, after an intermediate 2nd edition, the book was expanded to about 250 pages. The only review (excepting Amazon) is here:

www.megalithic.co.uk/article.php?...

[2] The project is based on the idea that Stonehenge was a summary of a search for knowledge about the world and the Cosmos.
After the initial pdf summary, a short expanded (76 page) booklet was published. Now difficult to find, the only review of that is below:

www.megalithic.co.uk/article.php?...