The rock formation identified is at the surface throughout the Orkney Islands. The River Avon seems to be at least close to navigable by a barge carrying a 5m long stone, requiring less than a mile of transport across land to Stonehenge. So it doesn't seem to require extremely implausible means to get it there. As to why -- perhaps the Stonehenge civilization came from Orkney originally, bringing their sacred stone with them? Or perhaps Orkney was a sort of Rivendell back then -- it's easier to defend as an isolated island group. You might go get a big stone from the monks there to establish the authenticity of your satellite colony.

I wonder what the Avon looked like back then?

The waters down the west coast can be a little hairy. I asked Claude to analyze the paper and speculate a route and it thought the east coast route, then up the Thames and down the Avon was more likely?

"Modern oceanographic knowledge tells us that the Irish Sea can be challenging due to strong currents, frequent storms, and numerous shoals and sandbanks. These conditions were likely present in Neolithic times as well." (Claude)

> (Claude)

That certainly is a sequence of words consistent with the rules of English grammar. Can you explain what you think it contributes to the conversation? Are you suggesting it’s more likely to be semantically valid than other such sequences of words?

Interesting thanks :)

> I asked Claude to analyze the paper and speculate a route and it

utterly failed to mention glacial erratics.

https://en.wikipedia.org/wiki/Glacial_erratic

https://www.cyark.org/projects/okotoks-erratic/overview

Mind you, so did every other HN commentator and it's something that rarely comes up when forums speculate on the transport of stones in the UK for ancient monuments.

It's easier to stack up the "weird non local" stones dropped at the end of a valley after a glacial retreat than it is to transit them ~1,000 km without a crane and a truck.

The ring of Brodgar is in the area where this stone came from. There is also evidence of stone circles underwater near to it from before sea levels rose at the end of the last ice age. If your religious sites were getting inundated I imagine you'd try to move the most important part of them as far away from the area as possible and to higher suitable ground. So Stonehenge may exist as a consequence of ancient climate change :). The river Avon at Amesbury had population centres in Neolithic times. The Old Sarum hill fort near Salisbury for example.

I'm not surprised that they could, I'm more surprised that they wanted to.

What else was there to do? There was no Internet, no television, no football (perhaps), no books, no broadcast radio.

I'm only half joking.

Maybe someone was "visiting" Scotland, and decided that it would look good in their backyard

Yea, ancients had a certain taste for decorations.

For example in Assyria, to get an audience with their king Ashurbanipal, I believe, one had to go through a corridor full of heads of king's defeated enemies.

We often forget how violent past was. It was extremely hard to live to adulthood without killing anyone.

See also: Stone of Scone.

Fascinating but also a lot more portable

Although humans from this period are anatomically the same as us, their culture isn't much like ours and the things you're talking about are a matter of culture.

The specifics are a matter of culture, but every civilization has transportation and trade. That's universal.

>every bit as clever and complex as us

5000 years is a long time for adaptational/behavioral selection in the comparatively - compare to other large mammals - dense society. During the well observable last couple centuries we see significant changes in the average human height, aggressiveness and testosterone production, socials skills, even IQ level noticeably drifts over just few generations being the subject of economical and societal mass-selection process. You can't just dismiss the selective effect of mass culling events like wars, revolutions, Inquisition and similar societal level massive behavioral-based selection processes adjusting the society for specific traits (for example Russian revolution killed several millions most educated people, and later Stalin "adjusted" the society by killing several millions of people who tended to be less-conformists), executing over the centuries or later putting in prison significant number of people with specific social/behavioral traits, etc.

I see people strongly disagree. I wonder how those people would explain how similar selection actions produce such strong changes in just a few generations of say dogs or cows.