Crystals 'helped Viking sailors' (For Viking fans....and others, of course).

BBC ^ | Wednesday, February 7, 2007

[Jedi Master Pikachu]

The sun was not necessary for Vikings to navigate, say researchers

Vikings may have used a special crystal called a sunstone to help navigate the seas even when the sun was obscured by fog or cloud, a study has suggested.

Researchers from Hungary ran a test with sunstones in the Arctic ocean, and found that the crystals can reveal the sun's position even in bad weather.

This would have allowed the Vikings to navigate successfully, they say.

The sunstone theory has been around for 40 years, but some academics have treated it with extreme scepticism.

Researcher Gabor Horvath from Eotvos University in Budapest led a team that spent a month recording polarisation - how rays of light display different properties in different directions - in the Arctic.

Polarisation cannot be seen with the naked eye, but it can be viewed with what are known as birefringent crystals, or sunstones.

Birefringence, or double refraction, is the splitting of a light wave into two different components - an ordinary and an extraordinary ray.

The researchers found that the crystals could be used to find out where the sun was in the sky in certain foggy or cloudy conditions.

It is already thought that Vikings used sundials aboard ships to navigate.

Vikings were a seafaring race from Scandinavia who used their longboats to explore and conquer parts of Europe, Greenland, Iceland and Russia.

[leilani]

Latest Must-Have Accessories for the Nav Station Ping

[Cardhu]

This has nothing to do with the Vikings but I believe the Arabs sailed north and south up the coast of India and Africa using the Al Kemal (sp) plate, a square metal plate with a knotted string at the center. When in sight of land the plate held with the base on the horizon and the moved forward and backward until the North star touched the top of the plate. A knot was tied in the string at the point where it touched the nose to denote that specific headland.

Thereafter, in bad weather or out of sight of land they knew their latitude with reference to the coast of Africa or India.

Apparently the Polynesians had a similar method when sailing the huge Pacific. They used the magic gourd. A gourd with two holes in it that represented the position of the islands in relation to the north star.

Sail south and on the return find the exact latitude of your islands by using the magic gourd and turn right keeping the north star aligned at arms length with the base on the horizon. .those two holes in your water filled gourd to maintain it level in a moving environment. This way you would know when you moved either north or south of your intended track.

The height of the magician in the boat and the water level also made an artificial horizon. Navigation was always one of the dark arts.

I read about these things in a navigation book about 60 years ago which simply explained the principles before all the complexities were discussed. Of course knowledge of Longitude came much later.

[Paisan]

OK, change that to ALMOST always. If, as you claim, I don't know what I'm talking about, then the counter-claim is that the sun is NEVER visible during full overcast.
I will not debate this with you. Too many years sailing out of Boston Harbor, in weather fair and foul, have taught me otherwise.

[Ready4Freddy]

LOL! Thanks, leilani!

[GATOR NAVY]

...change that to ALMOST always...

Okay, since my primary objection was to the use of "always", I'm satisfied. Although my experience has been more along the line the sun is sometimes visible through a full overcast.

To let you know where I'm coming from, the majority of my sea time was the W Pacific, but I've been in every major basin except the Arctic and the S Atlantic.

Also, in the Navy on ships without aerographers, which was every ship I was on, navigation was responsible for the hourly weather observations. So between celestial and weather obs, I've spent a lot of time looking at the sky at sea.

[Paisan]

Thank you for your service, sir.

[SunkenCiv]

[RFEngineer]

“The Maori were (and are) a very fierce and proud warrior society and they would most naturally have sought to be well-fed. “

Cannibalism as a positive cultural feature is not something I’m prepared to sign on to.

Name one successful cannibal society. You can’t find one. What I would say is that if a seafaring society is too lazy to fish that they turn to cannibalism to be “well fed” is probably closer to the truth.

The Maori themselves would not brag about their historical cannibalism. They seek to downplay it. It is often excused in the clintonian fashion: “Everybody did it”

No successful culture practices cannibalism. If the white man hadn’t shown up to Australia and New Zealand, the Maori would still be cannibals, if there were any left at all.