Ancient Vikings were very good mariners. They crossed wide seas with none of the navigational equipment we have today, instead relying on their knowledge of the sun and the stars. But a question that has always plagued archaeologists, is how did they accomplish this on the Atlantic, which can often be a pretty soggy, foggy, and altogether nasty place?
According to Viking legend, they used a 'sunstone,' a magical device that allowed their navigators to read the celestial positions even in deep fog. And now, archaeologists think they've found what it was.
Researchers at the University of Rennes in France have put together all the evidence they've found, and have wound up with something quite plausible. While not magical, the device was a transparent calcite crystal, known as an 'Iceland Spar,' that ancient navigators would've used to depolarise light - meaning that the crystal was able to split light along two different axes.
In practice, that means that a sailor simply had to put a dot on top of the crystal, and then look at it from below. The incoming light would hit the dot, and create the illusion that it was duplicated. This optical effect was apparently all ye olde sailors needed to be able to locate the sun, even when it wasn't even visible.
In case you didn't get that, (I sure didn't), lead researcher Guy Ropars has a less technical version:
"Then you rotate the crystal until the two points have exactly the same intensity or darkness. At that angle, the upward-facing surface indicates the direction of the Sun. A precision of a few degrees can be reached even under dark twilight conditions...Vikings would have been able to determine with precision the direction of the hidden Sun."
These precursors to the compass were also used later on, being considered more reliable than the newer compass due to the fact that the presence of metal didn't affect it.
I'm still saying it's magic.
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