Greenland’s Viking Compass, Early GPS


Greenland revealed its own little jewel of its early history — a compass that was used like a GPS by the Vikings which had helped them navigate the waters in the dark. The compass was discovered in 1948 in an 11th-century convent in Uunartoq, Greenland. Recent research suggests that the Vikings may have used the compass, known as the Uunartoq disc, as an important navigational tool to sail across 1,600 miles of sea between Norway and Greenland. With only half of the disc remains, researchers estimated that its diameter to be about 7 centimeters (2.8 inches) which may once had a pin that jutted out in the center to cast a shadow to indicate a certain direction.

The Viking compass wasn’t like a magnetic compass the ancient Chinese used. Hungarian researcher Balázs Bernáth and his colleagues believed that the compass was used together with other tools, such as a flat wooden slab and a pair of crystals — called sunstones — that is made of calcite crystal. When the compass and the crystals were used together, they helped the Vikings navigate in the wee twilight glow at night since the summer nights in the northern seas aren’t completely dark. The faint twilight still cast small shadows upon the sunstones, which have a strange property that create a double refraction of sunlight, even when the conditions are cloudy or foggy. The sun’s position can be located by turning the crystals in front of the navigator’s eye until both shadows were equal.  This allows the Vikings to plot their course almost 24-hours a day.

In 2013, after Bernáth and colleagues recreated the compass and took the Viking sailing challenge, they concluded that the Viking compass is more likely to work under clear blue skies and less likely to perform well in cloudy conditions. However, it had only four degrees of error, which was much more accurate than relying on stars and other heavenly landmarks and was just as accurate as a modern magnetic compass.


Some people had speculated that during their voyages to and from Greenland, the Vikings may also had other uses of their compass besides using it like a GPS, such a symbol of protection known as the Vegvísir — meaning “guidepost” or “direction post” in Icelandic. However, this may likely be a misnomer because the symbol is actually from a 17th century Icelandic “magic book” called Galrabók, which had ties to medieval witchcraft, mysticism, and occultism, according to The Viking Runes. The Vegvísir has little relations to ancient Germanic faith, rituals, and traditions. With a 600-year gap between the end of the Age of Vikings and the writings of the Galrabók, the Vegvísir does not represent Viking culture– unless new evidence shows otherwise.

Greenland may harbor more evidence or new discoveries about the Vikings’ culture and history. The analysis and experimentation of the compass challenge the stereotype that Vikings were blood-thirsty savages that just pillaged and terrorized northern European between the eighth and 11th centuries. The clever and simple navigation device shows that they had ingenuity that allowed them to sail the high seas in the dark that few other cultures at the time could perform.


By Nick Ng


Applied Optics

Live Science

The Viking Rune