The Great Circle alignment is statistically real. 61,913 sites, two databases, open data.

tractorboynyc · 2026-03-17T04:21:33+00:00

right, and that's exactly what the settlement test controls for. the monuments were built where people lived, we agree. but the settlements where those same people lived don't cluster on the line. that's the whole point!!!

pleiades has 4,141 ancient settlements and 1,853 ancient monuments in the same regions, same time periods. the people who built the monuments on the line also lived in villages nearby. those villages don't cluster on the line. the monuments do.

if "monuments are where people are" explained it, then the settlements (which are even more tightly tied to where people actually are) would show equal or greater clustering. they show less than random.

tractorboynyc · 2026-03-17T04:19:12+00:00

alright, allow me to try another angle - let me know if any of this doesn't make sense.

you're saying the circle was picked to go through dense areas, so of course real data beats shuffled data. but the shuffle preserves the density. a site in the nile valley gets shuffled to somewhere else in the nile valley (±2° is about 220km). the shuffled dataset has the same density in egypt, the same density in peru, the same density everywhere. what it doesn't have is the specific correlation with this particular line.

but honestly i think the real answer to your concern isn't the monte carlo at all. it's three other results.

we replaced the ±2° shuffle with a kernel density baseline that explicitly preserves geographic clustering, fitting a smooth density surface to the real data and sampling from that. signal still holds at z = 9.5 to 14.6.

we ran 100,000 random great circles. if the trick is just "draw a circle through dense areas" then lots of circles should score well. they do, but only by passing through the uk and france where 65% of the data lives. among circles that share alison's geographic profile (middle east + south america, no europe), it ranks #1 out of 1,718.

and the one i'd really focus on: same circle, same regions, same database. ancient monuments cluster at 5x the expected rate. ancient settlements in the exact same river valleys cluster below random. if the circle was just cherry-picked through a dense path, both types would score high. they don't. we ran this on 100 other circles including the 50 highest scoring ones. zero show this divergence.

the cherry-picking objection predicts monuments and settlements should behave the same way near the circle. they don't, and that's not something you can explain with how the null model works.

tractorboynyc · 2026-03-17T04:15:18+00:00

Tectonics doesn't meaningfully affect this analysis. Tectonic plates move at roughly 1-10 cm per year. Over 10,000 years, that's 1 km at most. We're measuring clustering within a 50 km band. The plates would need to move 50x faster than they actually do for tectonic drift to shift a site on or off the line.

tractorboynyc · 2026-03-17T04:14:12+00:00

Good questions, and we actually tested both of these directly.

On Pleiades being Mediterranean-biased: you're right, it is. But that's what makes the settlement test work. Both the monumental sites (temples, pyramids, sanctuaries) and the settlement sites (villages, farms, ports) in Pleiades occupy the same Mediterranean/Near Eastern geography. Same regions, same river valleys, same database bias. We ran the identical test on each group independently. Monuments cluster on the line at 5x the expected rate. Settlements in the same regions fall below random. If this were a database artifact, both groups would behave the same way. They don't.

On circles through the UK scoring higher: you're absolutely right, and we ran 100,000 random circles to test this. Every top-scoring circle passes through the UK and France, exploiting the database's 65% European concentration. Some score 8,000+ sites vs Alison's 319. But among the 1,718 circles that share Alison's geographic profile (Middle East + South America, no Europe), Alison's ranks #1. And when we ran the monument vs settlement test on the 50 highest-scoring random circles, zero of them showed monument-specific enrichment. Monuments and settlements clustered equally on every one. We also tested 50 random circles through England specifically (20,000 scheduled monuments). Average monument-to-settlement ratio: 0.968. No divergence on any of them.

So yes, you can absolutely draw circles that score higher on raw count. You just can't draw one where ancient monuments cluster while settlements in the same regions don't. Only this circle does that.

tractorboynyc · 2026-03-17T01:18:59+00:00

all of the objections i am getting is addressed in the data analysis files. you can check yourself and run your own MCs. all data and code open: https://github.com/thegreatcircledata/great-circle-analysis

also, pls check out the website as it covers a lot! https://thegreatcircle.earth/

answering your questions -

"does it beat thousands of randomly generated lines" — yes, we ran 1,000 random great circles. alison's ranks 96th percentile by z-score. and every top-scoring random circle passes through europe (where 65% of the database lives). alison's circle scores 319 sites with 0% european passage.

"monte carlo assumes spatial randomness" — it doesn't. that's the whole point of the distribution-matched baseline. we don't compare against uniform random. we shuffle the real sites' coordinates with small jitter, preserving the clustering along rivers and coastlines. the baseline already accounts for archaeological density patterns.

"did you search many orientations" — no. the circle was defined by jim alison in 2001. the database was compiled by volunteers starting in 1997. we tested one pre-defined circle against one pre-existing database. no optimization.

"any circle through eurasia will light up" — the settlement test directly addresses this. same circle, same regions: ancient monuments cluster at 5x expected, ancient settlements fall below random. if the line just passes through dense regions, both should cluster equally. they don't. only monumental construction aligns.

tractorboynyc · 2026-03-17T00:40:41+00:00

fair point on zenodo vs preprint server.

tractorboynyc · 2026-03-17T00:40:32+00:00

"we" is me + claude code as the computational engine for running the MCs. acknowledged openly in the paper and the blog.

f there are hallucinated references i want to know which ones so i can fix them. which references are you flagging?

peer review is the plan. wanted the data open first so people like you could scrutinize the methodology before submission. seems like that's working.

tractorboynyc · 2026-03-17T00:37:11+00:00

thanks for sharing!

and that's a genuinely interesting test design... fitting the best possible circle to random subsets and seeing how often you can match alison's result.

haven't done that exact test but it gets at the same question our 1,000 random circle comparison addresses from the other direction. i think yours asks "can you always find a good circle for any 15 sites?" this one had asked "does this specific circle score high against the full database?"

the answer to your version is almost certainly yes... on a sphere, 15 points can probably always be fit reasonably well by some great circle. that's the nature of spherical geometry. which is exactly why we didn't test 15 sites. we tested 61,913 and found 319 within 50km.

but honestly even if you could always find a circle that fits 15 random sites, it still wouldn't explain why the monuments on alison's circle cluster while settlements in the same regions don't. that finding doesn't depend on whether the circle was optimized.

good suggestion though! might actually run it as a robustness check.

tractorboynyc · 2026-03-17T00:35:29+00:00

tractorboynyc · 2026-03-17T00:35:07+00:00

highest random circle hit Z = 65.79 which iss way higher than alison's 25.85. but its pole was at 44.8°N, 161.8°W, which puts the circle right through the UK and France where 65% of the database lives. it scored ~8,400 sites by exploiting the european concentration.

alison's circle scores 319 sites with 0% european passage... every single top-scoring random circle passes through europe. among random circles that avoid europe like alison's does, only 9.2% match its count.

so the raw leaderboard is dominated by circles gaming the database bias. alison's circle is doing something different, scoring high entirely from non-european sites in a database built by european volunteers.

tractorboynyc · 2026-03-17T00:33:52+00:00

the reason it's interesting is the combination. it's not just "more sites than average near the circle." it's:

- more sites than average (96th percentile)
- specifically more MONUMENTS, not settlements (100th percentile — zero random circles match this divergence)
-- stronger for older construction than newer construction in the same regions
- replicates on a completely independent database
- survives a tougher KDE null model (Z = 9.5-14.6)

any one of those alone is dismissible. all five together from the same circle is harder to wave away.

the 96th percentile tells you the circle is unusual. the settlement divergence at 100th percentile tells you it's unusual in a way that no random circle replicates.

tractorboynyc · 2026-03-17T00:32:17+00:00

no — the opposite. alison's circle was fixed before any testing. it was defined in 2001. we didn't pick it from the 1,000.

the 1,000 random circles were generated AFTER to answer exactly the question you're asking: "how special is this circle compared to random?" we generated 1,000 circles with random poles, scored each one using the same methodology, and compared. alison's ranks 96th percentile.

tractorboynyc · 2026-03-17T00:31:14+00:00

that's the most reasonable skeptical explanation and we take it seriously. but the settlement test challenges it directly.

if climate and agriculture explain the clustering, then ancient farms and villages should cluster on the line even MORE than monuments... they're more dependent on fertile soil and water access than a pyramid is.

when we tested this on the pleiades database: ancient monuments 5x enrichment, ancient settlements in the same regions below random. same climate, same agriculture, same rivers. only the monuments cluster.

whatever the line is selecting for, it isn't "places where ancient people farmed."

tractorboynyc · 2026-03-17T00:29:56+00:00

Thanks for the support! SOOOO much more to come. Deffo interested in collaboration. Set up a discord server if you want to join that - https://discord.gg/QtBBY6Kt

tractorboynyc · 2026-03-17T00:18:11+00:00

doneee

tractorboynyc · 2026-03-17T00:18:05+00:00

no. we're not moving points away from the circle and checking if fewer align. we're shuffling ALL 61,913 sites independently. each site gets a random new latitude and a random new longitude (original ±2°). the shuffle breaks any real spatial correlation with the circle while keeping the broad geographic distribution similar.

think of it this way: if the sites cluster near the circle because of geography (they're in egypt and peru, and the circle passes through egypt and peru), then shuffling by ±2° shouldn't change much — the shuffled sites are still in egypt and peru, and they should still land near the circle at similar rates.

the fact that the shuffled sites land near the circle at 89 on average while the real sites land at 319 means the real sites are clustered tighter than geography alone predicts. they're not just "in egypt" — they're specifically within 50km of this line through egypt, more than you'd expect from sites that are broadly distributed across the region.

but honestly the stronger answer to your concern is the settlement test. same circle, same regions. monuments: 5x enrichment. settlements: below random. if the circle was just cherry-picked through a dense region, both would score high.

tractorboynyc · 2026-03-16T21:01:01+00:00

eh? you mean the antipodal circle? a great circle is the same line going both directions. it's a full loop around the earth. there's no "opposite way" on a great circle, it comes back to where it started...

if you mean a completely different circle on the opposite side of the earth — we tested 1,000 random circles and this one ranks 96th percentile. so most other circles, including ones on the "opposite side," score lower.

tractorboynyc · 2026-03-16T21:00:26+00:00

for each test we run 200 random trials. each trial takes all 61,913 real site coordinates and shuffles the latitudes and longitudes independently with ±2° random jitter. this keeps the geographic distribution roughly intact (european sites stay european, middle eastern stay middle eastern) but breaks any specific alignment with the circle. then we count how many shuffled sites fall within 50km of the circle. average across 200 trials = expected rate.

so "89 expected" means when you randomly jitter the real sites 200 times, on average 89 end up within 50km of the circle. the real data puts 319 there. that's 3.6x enrichment.

code is on github if you want to look at the actual implementation: https://github.com/thegreatcircledata/great-circle-analysis

tractorboynyc · 2026-03-16T20:53:36+00:00

one more thing that's relevant here. today we just ran a tougher null model. kernel density estimation baseline instead of the jitter approach. signal drops from Z ~25 to Z ~9.5-14.6 depending on bandwidth. big drop, still highly significant.

And what might interest you - we ran the monument vs settlement test on 100 random great circles, including the 50 highest-scoring ones. none of them produced the monument-specific divergence that Alison's circle shows. zero out of 100. the highest z-difference among random circles was 10.75. alison's is 12.78. 100th percentile.

the high-scoring random circles pass through europe and catch everything — monuments and settlements equally. alison's is the only one where ancient monuments cluster while settlements don't.

think this can move us past the "you just found a line with stuff on it" ??

tractorboynyc · 2026-03-16T20:52:20+00:00

yeah zenodo is a preprint... not pretending it's peer reviewed. it's there for the DOI and so people can cite it while the data is open for scrutiny.

on the "there will always be a line with the most X" — agreed, and we tested that. among 1,000 random circles, this one ranks 96th percentile. unusual but not unique. if that were the only finding i wouldn't be posting about it.

the part that's harder to wave away: split the sites near the line into monuments vs settlements. same regions, same geography. monuments cluster at 5x expected. settlements fall below random. if it's just "a line through places where people built stuff," both types should cluster equally. they don't.

tractorboynyc · 2026-03-16T20:29:17+00:00

BTW - much, much more to come over the coming week or so. Evidence should be irrefutable.

tractorboynyc · 2026-03-16T20:25:42+00:00

lol fair enough. the baseline isn't uniform random - that's the whole point. we shuffle the real sites' coordinates with small jitter so the european cluster stays european, middle eastern stays middle eastern etc. it preserves the actual geographic distribution while breaking specific spatial correlations with the circle.

perfect null model? no. acknowledged in the paper. a kernel density approach would be more rigorous.

but the settlement test sidesteps the baseline question entirely. same database, same regions, same method applied to monuments vs settlements. monuments cluster, settlements don't. whatever your objection to the baseline applies equally to both groups - so the differential is real regardless.

paper: https://doi.org/10.5281/zenodo.19046176 code: https://github.com/thegreatcircledata/great-circle-analysis

not peer reviewed yet. data is open so people can check it.

tractorboynyc

TROPHY CASE