New In Science: Viking Navigation Secrets

A discovery that, if it proves out, may be of some interest to us! 
To avoid getting lost on their voyages across the North Atlantic 1000 years ago, Vikings relied on the sun to determine their heading. (This was long before magnetic compasses were available in Europe.) But cloudy days could have sent their ships dangerously off course, especially during the all-day summer sun at those far-north latitudes. The Norse sagas mention a mysterious "sunstone" used for navigation. Now a team of scientists claims that the sunstones could have been calcite crystals and that Vikings could have used them to get highly accurate compass readings even when the sun was hidden. 
The trick for locating the position of the hidden sun is to detect polarization, the orientation of light waves along their path. Even on a cloudy day, the sky still forms a pattern of concentric rings of polarized light with the sun at its center. If you have a crystal that depolarizes light, you can determine the location of the rings around the hidden sun.
If you are interested in how it read in the sagas, try this:
The weather was thick and snowy as Sigurður had predicted. Then the king summoned Sigurður and Dagur (Rauðúlfur's sons) to him. The king made people look out and they could nowhere see a clear sky. Then he asked Sigurður to tell where the sun was at that time. He gave a clear assertion. Then the king made them fetch the solar stone and held it up and saw where light radiated from the stone and thus directly verified Sigurður’s prediction.


MikeD said...

Never confuse technologically primitive with unsophisticated.

Lars Walker said...

I'm still not entirely sure why this story is news now. The basic information has been known for years. Somebody tested it again, and again it proves possible. Doesn't move the ball down the field much.

Grim said...

Well, the reason the story is in the news is that the journal article was just released. I think reducing error to 1% is pretty good for a guessed-at reproduction (no one, as you know, has ever found a real one to use as a model). It's possible that the Vikings themselves were able to refine the technology even more.

Mark said...

The Vikings also used a gadget that looked something like a little sundail mounted on a wooden handle to navigate. It had little pegs on the circumference and was, I suppose a primitive ancester of the sextant.

Lars Walker said...

Yes, and that's also disputed. It unquestionably works, but some archaeologists insist that the "dial" is actually just a bit of ecclesiastical furniture decoration, and was never used as a compass.

To complicate the matter, other historians claim that this sundial device, in a stone version, is actually what the sagas mean by "sunstones."

This is what keeps academic historians in business.