Secrets Of Legendary Viking Crystal Sunstones And The Mysterious Uunartoq Artifact Unraveled

MessageToEagle.com - In ancient times, the Vikings explored strange new lands and visited many distant places located across the ocean. While voyaging on the seas, how did the Vikings know where they were going?
There are several ways Vikings navigated. One method for navigating was to observe migrating animals. Another way was to observe the stars.
The Norse sagas also mention a mysterious "sunstone" used for navigation.
One of the reasons why the existences of sunstones have long been disputed is because they are contained in the saga of Saint Olaf, a tale with many magical elements.
However, this has changed and now. Sunstones can no longer be considered just a myth.
Archaeologists have discovered a special crystal that suggests legendary Viking sunstones did exists in reality.

The crystal uncovered in the 1592 sunken Elizabethan shipwreck near the Channel Islands, between England and France is shown to be an Iceland spar.


The research team headed by scientists at the University of Rennes says the stone was next to a pair of navigation dividers, suggesting it may have been kept with the ship's other navigational tools.It is believed that Vikings used so-called sunstones as a compass to find their way in arctic waters. Researchers suggest that sunstones could have been held up toward the center of the sky, allowing sunlight to hit it and get polarized and broken into an "ordinary" and an "extraordinary" beam.

On a clear not cloudy day, they could have rotated the crystal until the pair of beams lined up. By noting where the sun was when this happened, navigators could make a reference point to use even when the Sun was obscured by clouds or twilight.
If the crystal is held east-west, the double image becomes a single image and thus allows a sailor to locate the Sun.


This crystal found at the Alderney shipwreck. Image credit & copyright: Alderney Museum
According to the study published in the journal Proceedings of the Royal Society A."such a crystal immersed in sea water play a crucial role by limiting the solubility, strengthening the mechanical properties of the calcite, while the sand abrasion alters the crystal by inducing roughness of its surface.
Although both phenomena have reduced the transparency of the Alderney calcite crystal, we demonstrate that Alderney-like crystals could really have been used as an accurate optical sun compass as an aid to ancient navigation, when the Sun was hidden by clouds or below the horizon.
To avoid the possibility of large magnetic errors, not understood before 1600, an optical compass could have helped in providing the sailors with an absolute reference. An Alderney-like crystal permits the observer to follow the azimuth of the Sun, far below the horizon," the research team writes in the science paper.


As highly skilled navigators, Vikings crossed thousands of kilometres of open sea.
Credit: Bryba Prods/united Artists/The Kobal Collections
It is doubtful archaeologists will ever uncover a complete crystal in a Viking site because Vikings preferred to commit their dead to funeral pyres, cremating them and their grave goods.
Then there is the mysterious Uunartoq artifact that could shed more light on how Vikings navigated 1,000 years ago. The disc is estimated to have been about seven centimeters in diameter.
Researchers based at Eötvös Loránd University in Hungary have studied the Uunartoq artifact that was discovered in an 11th century convent in Greenland in 1948.


Click on image to enlarge The Uunartoq disc. Credit: Proceedings of the Royal Society 

When the artifact was discovered some dismissed it as simply a decorative object. Other scientists believe that the Uunartoq disc was used as a compass by the Vikings as they traversed the North Atlantic Ocean from Norway to Greenland.

"Vikings routinely crossed the North Atlantic without a magnetic compass and left their mark on lands as far away as Greenland, Newfoundland and Baffin Island.

Based on an eleventh-century dial fragment artefact, found at Uunartoq in Greenland, it is widely accepted that they sailed along chosen latitudes using primitive Sun compasses. Such instruments were tested on sea and proved to be efficient hand-held navigation tools, but the dimensions and incisions of the Uunartoq find are far from optimal in this role.

On the basis of the sagas mentioning sunstones, incompatible hypotheses were formed for Viking solar navigation procedures and primitive skylight polarimetry with dichroic or birefringent crystals," a team of Hungarian researchers wrote in their science paper.

A closer examination of the Uunaritoq artifact reveals that disc could in fact have functioned as a single entity. However, it is more likely the disc was used in conjunction with other tools - including a pair of crystals and a flat, wooden slab - to help navigate when the sun was low in the sky or even below the horizon.
"When the sun is low above the horizon, even the shadow of a small item can fall off the board, and such situations are frequent in the northern seas," said study co-author Balázs Bernáth.
With help of the crystal sunstones, the Vikings could locate the sun after sunset. Such crystal calcite stones produce patterns when they're exposed to the polarization of UV rays within sunlight.
This means that when the crystals are held up to the sky, the orientation of these patterns cast within the stone can help pinpoint the position of the sun below the horizon. Once the Vikings had determined the position of the hidden sun, they could have used a specially designed wooden slab called a shadow stick to simulate the shadow of the gnomon based on the angle at which the hidden sun would hit it. The location of the outer edge of that imaginary shadow could then have been used to determine their cardinal direction.
The discovery of the crystal sunstone and the Uunartoq artifact provides us with valuable knowledge how the Vikings could navigate long distances so many years ago.


The Viking ships were silent, swift, and light enough to be pulled ashore
and carried over land.
The Norse saga tells:

"The weather was very cloudy. It was snowing. Holy Olaf the king sent out somebody to look around, but there was no clear point in the sky. Then he asked Sigurd to tell him where the sun was. After Sigurd complied, he grabbed a sunstone, looked at the sky and saw from where the light came, from which he guessed the position of the invisible sun. It turned out that Sigurd was right."

For a long time, this intriguing story baffled historians. Today, we know the mythical Viking sunstone was a polarizing crystal that was most likely used by the Vikings to successfully navigate across the North Atlantic to the New World.

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Paleorivers Flowed Across Sahara 130,000 to 100,000 Years Ago, 100 km Wide Ancient River Made Mighty Mississippi Seem Puny

Paleorivers Flowed Across Sahara 130,000 to 100,000 Years Ago, 100 km Wide Ancient River Made Mighty Mississippi Seem Puny

Paleoclimate simulations reveal potential 'green corridors' across North Africa. The role of the Sahara as a geographical filter and launch zone for dispersals of Homo sapiens out Africa is a controversial topic.

Three ancient river systems, now buried, may have created viable routes for human migration across the Sahara to the Mediterranean region about 100,000 years ago, according to research published September 11 in the open access journal PLOS ONE by Tom Coulthard from the University of Hull, UK, and colleagues from other institutions.

Researchers used a novel palaeohydrological and hydraulic modelling approach to test the hypothesis that under wetter climates c.100,000 years ago major river systems ran north across the Sahara to the Mediterranean, creating viable migration routes. They confirm that three of these now buried palaeo river systems could have been active at the key time of human migration across the Sahara.

Unexpectedly, it is the most western of these three rivers, the Irharhar river, that represents the most likely route for human migration. The Irharhar river flows directly south to north, uniquely linking the mountain areas experiencing monsoon climates at these times to temperate Mediterranean environments where food and resources would have been abundant. The findings have major implications for our understanding of how humans migrated north through Africa, for the first time providing a quantitative perspective on the probabilities that these routes were viable for human habitation at these times.

Simulated probability of surface water during the last interglacial. This figure details Archaeological sites, and an annual probability that a location has surface water. The archaeological data are derived from a number of sources (including. The findspots are characterized by Aterian and Middle Stone Age artefacts such as bifacial foliates and stemmed Aterian points and/or typical ‘Mousterian’ points, side scrapers and Levallois technology. Most are represented by surface scatters but where stratified examples exist these can be shown by dating (OSL and U-series techniques) and geomorphological setting to belong within MIS 5e

Credit: doi:10.1371/journal.pone.0074834.g002

Simulating paleoclimates in the region, the researchers found quantitative evidence of three major river systems that likely existed in North Africa 130,000-100,000 years ago, but are now largely buried by dune systems in the desert. When flowing, these rivers likely provided fertile habitats for animals and vegetation, creating 'green corridors' across the region.

At least one river system is estimated to have been 100 km wide and largely perennial. The Irharhar river, westernmost of the three identified, may represent a likely route of human migration across the region. In addition to rivers, the researchers' simulations predict massive lagoons and wetlands in northeast Libya, some of which span over 70,000-square kilometers.

Yearly average rainfall from a 25 year snapshot of an ESM experiment and catchment area (hatched region) as well as the time series of zonally averaged precipitation for two stripes south of the catchment highlighting the (i) South-North gradient of rainfall during the wet seasons (June to September) and (ii) the modelled year to year variability of the monsoon system. The data is drawn from 12 hourly precipitation data produced during a time-slice experiment of the last Interglacial (MIS 5e, ~124 ka BP) performed by the fully coupled atmosphere-ocean- sea ice-biosphere general circulation model of the Max-Planck-Institute for Meteorology. The ESM consists of the spectral atmosphere model ECHAM5 including the land surface model JSBACH and a dynamic vegetation module coupled to the general circulation ocean model MPIOM. The model runs for the atmosphere at a truncation T31, which corresponds to a horizontal resolution of ~300 km in the area under investigation

Credit: doi:10.1371/journal.pone.0074834.g001

"It's exciting to think that 100 000 years ago there were three huge rivers forcing their way across a 1000km of the Sahara desert to the Mediterranean -- and that our ancestors could have walked alongside them" said Coulthard.

Previous studies have shown that people traveled across the Saharan mountains toward more fertile Mediterranean regions, but when, where and how they did so is a subject of debate. Existing evidence supports the possibilities of a single trans-Saharan migration, many migrations along one route, or multiple migrations along several different routes. The existence of 'green corridors' that provided water and food resources were likely critical to these events, but their location and the amount of water they carried is not known. The simulations provided in this study aim to quantify the probability that these routes may have been viable for human migration across the region.

For the first time, the simulations demonstrate that Saharan “Humid Corridors” were highly likely during the last interglacial strongly re-affirming the viability of these routes as migratory corridors for early hominids. This research provides an unprecedented means of developing new hypotheses for past human, faunal and floral activity in this region and for validating the performance of palaeo climate simulations, according to the researchers.
Contacts and sources:

 Kallie Huss
Public Library of Science

Citation: Coulthard TJ, Ramirez JA, Barton N, Rogerson M, Brücher T (2013) Were Rivers Flowing across the Sahara During the Last Interglacial? Implications for Human Migration through Africa. PLoS ONE 8(9): e74834. doi:10.1371/journal.pone.0074834

Source: http://nanopatentsandinnovations.blogspot.nl/2013/09/paleorivers-flowed-across-sahara-130000.html