NASA Logo, National Aeronautics and Space Administration
Ancient Observatories, Timeless Knowledge

Sun-Earth Day Presents: Ancient Observatories, Timeless Knowledge

Multimedia Center
Image Gallery
Gotland Grooves

Gotland Grooves

The length of the grooves, found on thousands of stones on the island of Gotland, 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 length 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.Learn More»

Photo Credit: Soren Ganholm

NASA Logo -