New Scientist: Stonehenge may have been a giant calendar and now we know how it works


Say No 2 Net Validations
Oct 22, 2008

“All except two of the sarsens at Stonehenge come from that single source, so the message to me was that they’ve got a unity to them,” says Darvill. To him, this indicated that they were intended for a common purpose. To find out what, he looked for clues in the numbers.

The sarsens were arranged in three different formations at Stonehenge around 2500 BC: 30 formed the large stone circle that dominates the monument, four “station stones” were placed in a rectangular formation outside this circle, and the rest were constructed into five trilithons – consisting of two vertical stones with a third stone laid horizontally across the top like a lintel – located inside the stone circle.

“Thirty, 5 and 4 are interesting numbers in a calendrical kind of sense,” says Darvill. “Those 30 uprights around the main sarsen ring at Stonehenge would fit very nicely as days of the month,” he says. “Multiply that by 12 and you get 360, add on another 5 from the central trilithons you get 365.” To adjust the calendar to match a solar year, the addition of one extra leap day every four years is needed, and Darvill thinks that the four station stones may have been used to keep track of this. In this system, the summer and winter solstice would be framed every year by the same pair of stones.

This Stonehenge calendar system “makes a lot of sense”, says David Nash at the University of Brighton, UK. “I like the elegant simplicity of it.”

Others aren’t so sure. “It’s certainly intriguing, but ultimately it fails to convince,” says Mike Parker Pearson at University College London, UK.” The numbers don’t really add up: why should two uprights of a trilithon equal one upright of the sarsen circle to represent one day? There’s selective use of evidence to try to make the numbers fit.”

All interesting, but the last guy has a point, this seems a but dubious.
Would still be cool if we now had it figured out.


Oct 15, 2003
The Dream
What do you expect from shamans? It might have been a collection of solar clocks, but all the stones are way too close to each other to extrapolate anything more. Unlike a famous experiment with water levels in ptolemaic Egypt.


the resident Cassandra
Dec 4, 2006
Indeed it does look dubious.

Stone circles or any others may simply mean "we like to pile up stones like a gate" or "arrange them in a circle" or line or whatever. Just like the pyramids can simply mean "we thing marking a tomb with a big point pile of stones is cool".

It will be only guesses, the megalithic monuments. The pyramids at least we can hope for some contemporary testimonials, do have some. And none fantastic that I know of.


High Quality Person
Nov 29, 2006
I'm a little confused by this, I thought it was already established that Stonehenge was a calendar of sorts. The alignment of various triliths (thats the door looking things, right?) aligns too closely to the solar equinox to be a coincidence, and similar alignments are seen in other stone circles.

Am I missing something?


Oct 16, 2021
NES/FG/SF Activity:Arguing the toss
I thought it understood that much of the henge had been moved about by a farmer when making it into a tourist attraction?
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