Passage Graves and Astronomy

I meant to mention this before Christmas but somehow didn’t get around to it. has an interesting article on the astronomical orientation of passage graves in Denmark.

From the article:

With the help of GPS, a compass and a surveying instrument Claus Clausen measured the orientation of entrance tunnels of approximately 100 passage graves. It turned out that there was a remarkable concentration of certain orientations. Claus Clausen had a theory that it could be a calendar system, but the theory did not hold up. Astronomer and supervisor of the special project, Per Kjærgaard Rasmussen suggested that he look at the connection between the sun and the moon and especially lunar eclipses, because there were two orientations that occurred frequently and that could suggest something with specific full moons.

The article points out that there is a significant concentration of orientations to the east-southeast and equate this to the position of the rise of the full moon and suggest a ritual connection.
Since the story concerns Denmark, here is the obligatory Shakespeare/Hamlet reference – it seems that Shakespeare knew a little something about astronomy and displayed some of that knowledge in Hamlet.

3 Responses

  1. The article suggests that prediction of lunar eclipses (rather than observation) was involved:

    The calculations show, that in the period from 3.300 to 3.100 BC there was an over frequency of 50 percent in the number of lunar eclipses that could be seen in Denmark. And the exciting thing was that the pattern indicated that it could fit with the rise of the full moon immediately before a lunar eclipse.

    How the Stone Age people had known that a lunar eclipse would come after a full moon is unknown, but astronomer Per Kjærgaard Rasmussen explains, that if one had observed a lunar eclipse there is a very strong likelihood that another lunar eclipse would come either 12 months or 18.6 years later.

    However I don’t see anything in the article that requires prediction of lunar eclipses. Suppose the stone age people marked the orientation of the rise of each full moon. If a lunar eclipse followed, they used the orientation mark for the most recent full moon rise to decide the orientation for the next grave.
    In other words – there’s no indication of whether the grave orientation was decided before or after the lunar eclipse. To justify the phrase ‘How the Stone Age people had known that a lunar eclipse would come after a full moon is unknown’ requires evidence the grave orientation was decided before the lunar eclipse in question.

  2. The passage graves were build after an eclipse took place. Therefore the calculated distribution is consistent with the observed distribution.
    Claus Clausen

  3. Hi Claus. Thanks for the input!

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