New Analysis of a Crystal Viking 'Sunstone' Shows It Could Accurately Navigate the Oceans

Wednesday, 04 April 2018 - 7:21PM
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Wednesday, 04 April 2018 - 7:21PM
New Analysis of a Crystal Viking 'Sunstone' Shows It Could Accurately Navigate the Oceans
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Nowadays, you don't hear about crystals being useful unless you're talking to someone who believes in pseudoscientific "healing crystals". But they have real uses too, beyond just being nice-looking rocks (yes, we know, they're minerals).

A popular tale about ancient Vikings is that during 900 to 1200 CE when they were sailing the northern Pacific Ocean, they navigated using prismatic crystals like calcite, cordierite, and tourmaline which are capable of "splitting" a beam of sunlight into two, and can even show the location of the sun on a cloudy day using polarized light. These were commonly referred to as "sunstones".

Since there's no evidence that the Vikings had magnetic compasses, but also no evidence that they carried these sunstones, the concept of navigation via sunstone tends to be approached cautiously by historians. But a new study published in Royal Society Open Science ran a series of thousands of computer simulations of Viking voyages, and found that a sunstone could have accurately guided them on the open ocean. 



Researchers Dénes Száz and Gábor Horváth from Eötvös Loránd University in Hungary are among the first to really test whether a light-polarizing sunstone could navigate effectively. They tested out the crystals in question in 1080 different sky situations with a variety of sun elevations and levels of cloudiness. Using this, they now had a standard error for the crystals for the next part of their experiment.

After this, they started running computer simulations of a single boat trip from a point in Norway to a point in Greenland, replicating the likely paths of Viking ships, with a variety of different weather conditions and levels of cloudiness - and on two separate days, the spring equinox and summer solstice

There were 1,000 simulated voyages for each of the three types of crystals (calcite, cordierite, and tourmaline), and six different periodicities (how often the crystal was checked) on the two different dates, with 36,000 simulated voyages total.

They found mixed results, but in the best case, a cordierite sunstone consulted every three hours gave a 92.2-100% success rate that the virtual Vikings would safely reach the virtual Greenland coast. While there's still never been a sunstone of any kind found near a Viking shipwreck, the research at least validates the oral legends that it was possible. 

So, to put things in Mythbusters terms, an accurate Viking sunstone could be considered Plausible under the best conditions. If you're ever about to go sailing on the open ocean, and for some incomprehensible reason you choose not to bring a modern compass, you could bring a hunk of cordierite instead so you don't lose track of the sun.

Just make sure you read up on polarized light before you set sail.
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