Árvakr ok Alsviðr þeir skulu upp héðan svangir sól draga

May 1, 2018 5:43 AM

Without magnetic compass, clock, or GPS, how do you navigate in the North Atlantic when it's cloudy and you're out of sight of land? Vikings may have used sunstones and their ability to polarize light to find the hidden sun.

NYT article. Bonus: Some other Viking navigational tips and tricks.

posted by Eyebrows McGee (12 comments total)

I read a very thorough debunking of sunstones recently, but can I find it now? Of course not.

So I'll just have to settle for a prominent archaeologist pointing out on Twitter that no sunstones have ever been found in a "Viking" context.

Neat theory though.
posted by Helga-woo at 6:33 AM on May 1, 2018 [4 favorites]

I saw this recently; it’s so cool how it pops the sun out from behind the clouds.
posted by leotrotsky at 6:34 AM on May 1, 2018

Navigation, however, was no easy task. There was no map or chart to rely on, no sextant for celestial navigation, and no magnetic compass to help with dead reckoning. (That was how Columbus did it 500 years later.)

Another article on the mysteries of navigation. A mention of Columbus for some reason but no mention that Pacific islanders had pretty much mapped out the much larger Pacific Ocean thousands of years earlier.
posted by vacapinta at 6:46 AM on May 1, 2018 [8 favorites]

I did a post on Polynesian wayfinding last year!
posted by Eyebrows McGee at 6:55 AM on May 1, 2018 [4 favorites]

Here is somebody demonstrating a piece of Icelandic spar as a potential navigation tool - put a dot on the font of it and then look through it like a telescope. In most directions the double refractive qualities of the spar give you two dots - a black dot being the one on the front of the stone - and a purple dot. But point the spar in the direction of the sun and you see just one dot (because the refraction from the sun obliterates the second one in this direction). This works even though the sky may be overcast. If you know the direction of the sun - and you know how long since it came up (so hence: the date and some idea of your lattitude) - and you remember that it moves East to West at 15 degrees per hour - then you can work out which direction you are heading.

This is all very well in theory. But it sounds like it is past time for the people talking about sunstones as a navigation mechanism - to go get in a Norwegian boat and try to get to Greenland.
posted by rongorongo at 7:12 AM on May 1, 2018

Wondering where I had heard of Iceland Spar... must have been Pynchon's Against the Day. Interesting links on the Pynchon Wiki.

Also, possibly related- I used to work on high-end laser printers that used 2- or 4-beam scanning.
I think they used Wollaston prisms, which are calcite, and seem to do the same thing.
posted by MtDewd at 7:20 AM on May 1, 2018

FTA: "Stephen Harding, a biochemistry professor at the University of Nottingham and author of Science and the Vikings"

Excerpt:

The major breakthrough in sunstones was made by Dr. Eric Pillager, professor of bog chemistry at Yggdrasil Polytechnic University. Dr. Pillager could frequently be found late at night in his wooden lab, with electricity arcing between the twin horns of his Viking helmet, which he had fashioned into a crude also a Van de Graaff generator.

posted by compartment at 7:53 AM on May 1, 2018 [7 favorites]

From my understanding, sunstones are useless. However, magnetite located in the beaks of Vikings may be responsible for magnetoreception via trigeminal mediation. Experiments with magnets attached to the backs of Vikings demonstrated that disruption of the Viking's ability to sense the Earth's magnetic field leads to a loss of proper orientation behavior under overcast conditions.

More recent behavioral tests have shown that Vikings are able to detect magnetic anomalies of 186 microtesla.

Obviously though, more research is needed.
posted by happyroach at 10:08 AM on May 1, 2018 [6 favorites]

But it sounds like it is past time for the people talking about sunstones as a navigation mechanism - to go get in a Norwegian boat and try to get to Greenland.

I give you Björn Ahlander and the voyages of Draken H.H., coming back to the New World in 2018

(Okay, for all I know they have GPS under the rowing benches, but he's clearly holding up a sunstone in that video.)
posted by BWA at 10:15 AM on May 1, 2018 [2 favorites]

...it sounds like it is past time for the people talking about sunstones as a navigation mechanism - to go get in a Norwegian boat and try to get to Greenland.

Never underestimate Norsemen.

There's one in Norway too. I rode it (took that video) – grew up with a Norsk farfar (grandfather) who had quite a few boats – a McKenzie river driftboat, a big motored lake boat, a wooden lake rowboat that could seat 4, a small sailboat (good for 2 people at most), medium sailboat (4-6 people), and a couple of canoes. At this point I should probably add that his father was a boat construction foreman, so most of his boats weren't "expensive" if you looked at it from the point of view of dudes who cut down trees and built them, all except that lake motorboat made of fiberglass. I've been on everything from ocean motorboats to ferries to the big ships that run between Helsinki and Stockholm. The Viking boat? OMG. I've never experienced such a sense of exhilaration. The thing is stable and fast. I'd rather go to Greenland on one of those than on one of the hulking steel dullards I rode to Stockholm and back from Helsinki.
posted by fraula at 10:47 AM on May 1, 2018 [1 favorite]

And now we know why the Vikings never reached Australia: you can't use the sunstone navigation trick if there are no clouds.
posted by Joe in Australia at 4:36 PM on May 1, 2018

It's one of those weird obsessions because the Sagas and other old Icelandic texts are actually full of descriptions of ways that seafarers found their way around (or came upon unexpected lands because they were blown off course). In addition to that there's centuries worth of archeological finds that have been extensively studied. It's probably better understood how the Norse navigated their way around the North Atlantic than any other comparable historical seafaring society. Sunstones aren't really needed to explain their feats of navigation, though it's certainly possible that they could have used them.

As an aside, my ancestors owned the main Iceland spar mine in Iceland for a while.
posted by Kattullus at 12:15 AM on May 2, 2018 [2 favorites]