What is the secret behind the success of such accomplished sailors navigating the Vikings? The answer is a stone.
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| The Vikings Sun-stone. (Picture from: http://www.ravingravens.com/) |
A thousand years ago the Vikings were the rulers of the North Atlantic Ocean. Although there was as yet no compass, they can still know the location in the middle of the ocean by utilizing solar sail as a guide.
But not every day sunny. At certain seasons, clouds piled up above the sky so the sun's position could not have known. When this occurs, they switch to using wind as a guide. But the wind is often deceptive.
Viking Legend says, when the sky filled with clouds, sailors had to lift the stone into space to search for clues. The stone called the sun-stone and come from mainland Iceland.
Experts later learned that the sun stone formed from calcite crystals that have unique structures. The light that passed through a calcite crystal will separate into two parts, creating two shadows on the opposite side. Brightness level of the shadow depends on the polarization of light.
But not every day sunny. At certain seasons, clouds piled up above the sky so the sun's position could not have known. When this occurs, they switch to using wind as a guide. But the wind is often deceptive.
Viking Legend says, when the sky filled with clouds, sailors had to lift the stone into space to search for clues. The stone called the sun-stone and come from mainland Iceland.
Experts later learned that the sun stone formed from calcite crystals that have unique structures. The light that passed through a calcite crystal will separate into two parts, creating two shadows on the opposite side. Brightness level of the shadow depends on the polarization of light.
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| Map of Viking exploration. (Picture from: http://www.ravingravens.com/) |
Knowing this, Viking sailors direct sun stone into the air as she saw the shadow pattern. Though the sun hid behind clouds, the sun stone can be seen as concentric rings with the sun in the middle. As a result, the sun's position can be known.
Physicist from the University of Rennes, France, Guy Ropars, proved this technique to create a sun stone using calcite crystals from Iceland. This stone is mounted on a wooden device that pass light through a small point. Homemade sun stone Ropars able to know the position of the sun with an error rate of 1 percent, even when the sun was behind the horizon.
"This technique is a smart solution for navigation in the open ocean," said John Phillips, the navigation experts from Virginia Polytechnic Institute and State University.
Viking techniques are also used by birds, by revealing the position of the sun through the polarization of light. *** [WIRED | ANTON WILLIAM | KORAN TEMPO 3699]
Physicist from the University of Rennes, France, Guy Ropars, proved this technique to create a sun stone using calcite crystals from Iceland. This stone is mounted on a wooden device that pass light through a small point. Homemade sun stone Ropars able to know the position of the sun with an error rate of 1 percent, even when the sun was behind the horizon.
"This technique is a smart solution for navigation in the open ocean," said John Phillips, the navigation experts from Virginia Polytechnic Institute and State University.
Viking techniques are also used by birds, by revealing the position of the sun through the polarization of light. *** [WIRED | ANTON WILLIAM | KORAN TEMPO 3699]
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