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Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsEnglish Channel crystal may be fabled sunstone
A rough, whitish block recovered from an Elizabethan shipwreck may be a sunstone, the fabled crystal believed by some to have helped Vikings and other medieval seafarers navigate the high seas, researchers say.
In a paper published earlier this week, a Franco-British group argued that the Alderney Crystal a chunk of Icelandic calcite found amid a 16th century wreck at the bottom of the English Channel worked as a kind of solar compass, allowing sailors to determine the position of the sun even when it was hidden by heavy cloud, masked by fog, or below the horizon.
Thats because of a property known as birefringence, which splits light beams in a way that can reveal the direction of their source with a high degree of accuracy. Vikings may not have grasped the physics behind the phenomenon, but that wouldnt present a problem.
You dont have to understand how it works, said Albert Le Floch, of the University in Rennes in western France. Using it is basically easy.
Vikings were expert navigators using the sun, stars, mountains and even migratory whales to help guide them across the sea but some have wondered at their ability to travel the long stretches of open water between Greenland, Iceland, and Newfoundland in modern-day Canada.
http://www.hindustantimes.com/world-news/Europe/English-Channel-crystal-may-be-fabled-sunstone/Article1-1024314.aspx
talkingmime
(2,173 posts)The Straight Story
(48,121 posts)talkingmime
(2,173 posts)Tab
(11,093 posts)Berlum
(7,044 posts)Know what i mean?
grasswire
(50,130 posts)...as the character in the Vikings TV series tries to navigate to the West. A sunstone was introduced to viewers briefly, last week.
pam4water
(2,916 posts)And probably Thom Hartmann too.
pam4water
(2,916 posts)Read the articles on five sites before I under stood how it worked: XD
http://www.businessinsider.com/viking-sunstone-discovered-2013-3
The Straight Story
(48,121 posts)If you put a dot on top of the crystal and look at it from below, two dots appear, because the light is "depolarised" and fractured along different axes.
You then rotate the crystal until the two points have exactly the same intensity or darkness.
"At that angle, the upward-facing surface of the crystal indicates the direction of the Sun," Ropars told AFP in an interview in 2011, when preliminary research about the Alderney stone was published.
Read more: http://www.businessinsider.com/viking-sunstone-discovered-2013-3#ixzz2NBztZRK8