Solar Stone of the Vikings

Scientists discover a great secret of the Vikings: what is the solar stone, a mysterious tool to navigate on cloudy days. IX. In the 10th century, Viking navigation was ruled by the Sun, as the compass had not yet been invented. But on cloudy days it was more difficult to orient and use a "solar stone", as is said in the ancient documents of the Nordic Saga of the Vikings. However, the documents did not define what that stone was.

In 1967, the Danish archaeologist Thorkild Ramskou proposed that the scientific secret to orienting navigation is to detect the polarity of light, since from this detection it follows from where light rays come from. The stone could be a calcite crystal, very common in Scandinavia. Subsequently, scientists have tried to decipher the position of the Sun through calcite on a cloudy day.

The last session was conducted by physicist Guy Ropars of the University of Rennes 1. He has made a solar stone by inserting a calcite crystal into a wooden container and has measured the accuracy of the technique, according to his measurements the position of the Sun can be determined with a 1% error even after sunset. Experts have taken this measure as proof that the solar stone of the Vikings was a calcite crystal.