About the grooves in Gotland
There are about 3600 known grooves in stones in Gotland. 700 are in the bedrock, which is limestone, and the rest in about 800 stones. The lenght of the grooves varies from about 0.5 to 1 metre. They are between 5 cm to 10 cm wide and 1 cm to 10 cm in depth.
They are shaped as though they were made by a tool fixed on a pendulum, the cross section of the lenght of each mark being in most cases part of a circle.
The most important feature of the grooves is alignment. A study of 1256 grooves showed that they are aligned with certain positions of the celestial bodies, apparently the sun or the moon.
Stone with grooves from Stumle, Alva, Gotland
Map of the island of Gotland
Here 32 grooves in the bedrock have been dated. Gregorian dates (day, month, and year) are used. One metre is shown for scale. North is shown by the arrow.
Grooves at Hugraivs, Gammelgarn, Gotland
|The direction of each groove were measured. Then the distribution of the directions of the grooves around the horizon was graphed. I concluded that their orientation is not random. Computer simulations showed that the orientation of these marks is not random. Most of them are oriented east-west. Moreover, many are oriented towards the most northern or most southern rising and setting points of the moon. A professional astronomer, Göran Henriksson in Uppsala, Sweden, calculated the exact rising and setting times and directions of the moon many thousands of years into the past. An examination of one group of grooves--for example, the grooves on one stone, or on several adjacent stones, or those that lie close together in the bedrock--shows an interesting relationship. If it is assumed, as our theory suggests, that these grooves were made in the direction of the rising or setting of the full moon on a certain day, namely the winter solstice or the equinox, then it becomes possible to match each set of grooves with a set of dates calculated by Henriksson. . Since it is 19 years between such occasions and the direction varies in a complex way, it produces a pattern that is in some respects much like a fingerprint. The largest group dated consists of 32 grooves. It is very unlikely that a pattern like this could occur by chance. If the theory is correct, the oldest groove in this group was started March 19 in the year 3152 B.C. Then the second one was started nineteen years later--March 19 in the year 3133 B.C.|
Diagram of the directions of 1253 Gotlandic grooves.
Here are hyperlinks to some of the pages in the book about the grooves.
The book is in Swedish, but this is just the directions and maps and locations
of the grooves and there should not be problems to anyone to read.
Table of the directions of some groups of grooves. (The directions in degrees.)
Measured maps of the grooves
List of the locations of all the known Gotlandic grooves..
Created by Sören Gannholm
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