Neolithic 'sun stones' sacrificed in Denmark revives sun after volcanic eruption | Hacker News Reader

Neolithic 'sun stones' sacrificed in Denmark revives sun after volcanic eruption

archaeologymag.com

"Sun Stones" refers to two things.

1) crystals with an interesting polarised effect which allow you to identify the vertical plane of the sun in cloudy skies, and therefore effect navigation at sea in overcast daylight, modulo some basic idea of the time.

2) quasi religious carved stones, "sacrificed" by burial, in attempts to placate the gods over the awful horrors of a post-eruption landscape and climate.

The article is about the second kind.

> effect navigation at sea in overcast daylight, modulo some basic idea of the time

What do you mean with "modulo some basic idea of the time"?

The sun moves. You can't sail a constant linear course using a device which is sun seeking, unless you include some sense of time. It describes an arc in the sky, you'd be steering in a curve.

Happy to be told otherwise.

At dawn and sun set you don't need to know the time. But then again that is only twice a day to adjust course.

I wonder if you can track mid day with such a stone.

Without wishing to be over pedantic, that's modulo time at the granularity of a day, and with set points.

With a wish to be overly pedantic, if you can keep a somewhat steady course during the day, or anchor, and pick the mid point between sun set and dawn you don't even have to know the day of the year, time of the day, or anything time related.

I was mostly confused by the wording. I didn't know 'modulo' could be used like that, but apparently it has a colloquial meaning of "except for the variation accounted for by" and now the phrase makes sense to me.

It is interesting to note that in a 4900 year period it not very significative if they were saved by this ritual or all of the died in a 20 year span. But I hope they managed to see the sun again.

original title: Neolithic ‘sun stones’ sacrificed in Denmark to revive the sun after volcanic eruption

didn't see a good way to shorten.

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