How the Vikings navigated day and night. The secret of the "sun stones": how the Vikings got from Norway to Greenland almost blindly

For many decades, scientists have tried to unravel the mystery of the navigation of the Vikings, who, as you know, could swim quite long distances. They often sailed from Norway to Greenland, without losing their course and spending relatively little time on it. Of course, it is possible that they were able to perform such maneuvers thanks to compact Drakkar ships that swam quickly and kept well on the water. But there are legends that the Scandinavian navigators had special navigation aids, such as "sun stones". The secrets of their creation and use have not been unraveled to this day.

Disk Wunartok

There could not have been any navigation of a relatively modern magnetic type in those days. Sailors relied on the will of the Earth, hoping for good weather and the right course. They were guided by the position of the luminary, the stars, the moon, and the like. And only the northern seas, not distinguished by a mild climate, were a real test for the conquerors. How did the Vikings, who constantly encountered these seas, navigate them?

In 1948, a special artifact was found - the Uunartok disk with interesting marks. According to legend, the Vikings used it as a compass, combining it with some miraculous "solstenen" - "solar crystal".

In the records that were made during the Viking Age, one can often find information about the Uunartok disc. They wrote about him that this device is incredibly accurate, despite the uncomplicated design. The most interesting thing is that in those days such technologies were equated with witchcraft. How could mankind then invent such a high-tech device?

It is known that in the Christian world of the 9th-11th centuries, the Vikings were considered dirty and disgusting pagans. All other peoples thought that this people, which did not even have a state, could not have anything remarkable. It turned out that this is far from the case.

Scientists who studied the Uunartok disk suggested that this product is a kind of sundial with marks that corresponded to the cardinal points. Also in the central part of the disk there was a special hole - "gnomon". The light passing through it was compared with the marks on the disk, after which it was determined in which direction the ship was moving.

Practical experiments with the disk were carried out by G. Horváth, an employee of the Otvos University located in Budapest. He determined that if you keep the disc in clear weather in a certain position, then the shadow from his "gnomon" will fall on one of the marks. Comparing it with the marks on the compass, Horvath realized that the Viking device was amazingly accurate - its error did not exceed 4⁰. Thus, using it correctly, it was really possible to navigate.

It should be noted that in his report, Horvath reported some features. The disk turned out to be maximally effective only in the period from May to September, and only at a latitude of 61⁰. Based on this, it can be assumed that the Vikings used the ancient compass only in summer, when they made the maximum number of trips. The only thing that Horvath could not solve was the mystery of the "sun stone".

"Sun Stone" in mythology

For a very long time, scientists argued about the plausibility of the legends about the navigation of the Vikings, which indicated a certain “sun stone”. Skeptics said that it was an ordinary magnetic iron ore. Magical abilities were attributed to the "sun stone": it could summon the sun and emit a bright glow.

Archaeologist T. Ramskow from Denmark in 1969 put forward the theory that the magic stone of the Vikings must be sought among the now known crystals that have polarizing properties. The scientist began to study all possible minerals located on the territory of Scandinavia. As a result, he chose three contenders for the main role of the miraculous "solstenen": tourmaline, Icelandic spar and iolite. All of these crystals could have been used by the Vikings. It remained a mystery which of the above was "solstenen".

An Elizabethan ship shed light on the search for the real "solstenen" in 2003

In 1592, an Elizabethan ship sank near a Norman island called Alderney. The crash site was discovered in 2003, after which they began to study it in detail. In the captain's cabin of the sunken ship, they found a piece of transparent material, which, as it turned out later, was Icelandic spar.

This discovery forced scientists to think again about the "sun stone", which was completely forgotten for a while. Researchers G. Ropar and A. Lefloch decided to resume experiments on the creation of "solstenen", using feldspar of Icelandic origin as the main material. They published the results of their experiments in 2011. Their discovery amazed the entire scientific world.

It turned out that the functions of "solstenen" were based on the refraction of rays, which was described back in the seventeenth century by the Danish scientist R. Bertholin. The light penetrating the mineral was split into two beams. These rays have different polarizations, so the brightness of the images on the opposite side of the stone was also different and depended on the polarization of the source light. Simply put, in order to calculate the position of the Sun, it was necessary to change the position of the mineral until the images on its reverse side acquired the same brightness. This method is effective even in cloudy weather. Based on this, it can be assumed that the Icelandic spar could indeed serve as a navigator for the Vikings, and as accurate as possible.

Thousands of kilometers long, moving between settlements in Iceland and Greenland. And they didn't use compasses. Researchers have long been at a loss as to how the brave Scandinavian sailors managed to perform such feats time after time, especially given the weather conditions of the region.

A group of Hungarian scientists decided to get an answer to this question, and for this they turned to computer modeling and ".

According to stories about the Vikings, the so-called sun stones helped them navigate the terrain. According to legend, such stones helped to determine the position of the sun, even if it was hidden behind the clouds. The problem is that scientists have not found a single similar stone in the places of Viking shipwrecks.

"Actually, it's all just speculation," says biochemist Stephen Harding of the University of Nottingham, who was not involved in the study. However, he immediately adds that one of the possible evidence for the existence of sun stones can be considered a whitish mineral found next to other navigational instruments in a shipwreck of the 16th century.

Let's make a small digression here. We are talking about 1592, when one of the English ships sank near the island of Alderney in the English Channel, sailing to the coast of France to participate in the fight against the Spanish fleet. Four centuries later, divers raised fragments of the hull, equipment and weapons from the bottom of the English Channel to the surface. Among the finds was a white mineral in the shape of a rhombohedron the size of a small bar of soap. The authors of the project "Vesti.Science" (website) in detail about that discovery. Apparently, this mineral was really used for navigation.

According to Harding, there is every reason to believe that English sailors adopted some navigational "tricks" from the Vikings, who plied the same waters and raided the British Isles centuries earlier.

But back to sun stones: even assuming that such stones existed, how did they help the Vikings get from point A to point B?

Previously, experts have already uncovered the ability of several types of minerals (especially ultrapure crystals of calcite, cordierite and tourmaline) to polarize light. In this case, the light passing through the crystal is divided into two beams (polarized light has a different trajectory than unpolarized light). If you look at the sky through the crystal and rotate it, you can see concentric rings around the sun, and thus determine the direction to the luminary. Moreover, the stone allows you to find the location of the sun behind the clouds, large rain clouds or even beyond the horizon. The position of the luminary gives navigators a correct starting point during long journeys.

Theory is theory, but how does this method work in practice? As biophysicist Gábor Horváth of the University of Budapest, one of the authors of the recent study, notes, previous scientific papers have answered positively the question of whether minerals can be used to navigate. But this was not enough for curious scientists: Horvath, along with his colleague Denes Száz (Dénes Száz), included data from previous work in computer simulations of travels between Bergen, Norway, and the Viking settlement on the southeast coast of Greenland.

It is noted that such a journey could take about three weeks of day sailing, taking into account the typical speeds of Viking ships (11 kilometers per hour).

The calcite crystal, as in the photo, may have been the very Viking sun stone that allowed sailors to successfully travel such long distances.

In their paper, published in the scientific journal Royal Society Open Science, the authors write: using data obtained in earlier experiments, they determined the success of navigation using "sun stones". The scientists simulated 3,600 trips from Norway to Greenland, given varying cloudiness during the summer solstice and vernal equinox. Simply put, the experts wanted to understand how quickly (or even whether) the Vikings could reach Greenland under various weather conditions, depending on the methods of navigation (type of stones) and the frequency of their use.

To clarify, the vernal equinox is the supposed start of the Viking season on the high seas, and the summer solstice is the longest day (with the shortest night) of the year in the respective hemisphere.

The researchers took into account three factors: cloudiness (which varied throughout the day), the type of crystal used as a sunstone, and how often sailors used it. Each time the navigator "consulted" the sunstone, the simulated ship corrected course if necessary.

It turned out that if the sailors "taken readings" every four hours, then their ships reached Greenland in 32-59% of cases. But as soon as they consulted the stone every five or six hours, the chances of reaching land in the allotted time were noticeably reduced. And those who consulted the stone every three hours or more often reached the desired shores with a 92-100% probability.

All three types of crystals studied (calcite, a form of calcium carbonate, cordierite, a silicate rich in iron and magnesium, and tourmaline, a silicate rich in boron) were found to be equally beneficial when used every three hours or less. If the interval increased - up to five or six hours - then cordierite showed slightly better results, but calcite, a mineral known as Icelandic spar, was less suitable than other stones.

Nevertheless, the scientists conclude, all three crystals would be invaluable tools in the dangerous seas of the North Atlantic, and, apparently, some of them were used by the famous Vikings.

The simulation results showed that such navigation is really effective both on the days of the spring equinox and on the days of the summer solstice, even in cloudy weather. Of course, if the sailors determined the direction at least once every three hours (regardless of the type of "sun stone"), the authors of the work sum up.

You probably remember how we discussed who they are. Here in the sagas about the Norwegian Vikings there are references to the mysterious and magical "Sun Stone", with the help of which sailors could determine the position of the sun. In fairy tales about St. Olaf, the king of the Vikings, along with other magical items, some mysterious crystals are also mentioned, so the possibility of the existence of these stones was doubtful for a long time.

The brave Viking sailors did not know the magnetic compass (which, moreover, is useless in the polar regions), but at the same time they were perfectly oriented at sea, sailing to Greenland and North America. One of the ancient Icelandic sagas (late 9th - early 10th century) describes an episode of the Vikings sailing in cloudy weather, when it was not possible to navigate by the Sun: “The weather was cloudy and stormy ... The king looked around and did not find a shred of blue sky. Then he took a sun stone, raised it to his eyes and saw where the Sun sends its ray through the stone.

Back in 1967, Danish archaeologist Thorkild Ramskou put forward an explanation for these legends. He suggested that the ancient texts referred to transparent minerals that polarized the light passing through them.

Indeed, a polarizing filter directed at a cloudy sky allows you to determine where in the sky the polarization of light is maximum and where it is minimum, and from here you can understand where the Sun is located. Sunlight itself is not polarized, but clouds do. This method of navigation was discovered only in the 20th century and was used in polar aviation until the advent of the radio compass and satellite navigation, but the Vikings may have known it a millennium ago. By the way, bees use it on cloudy days, as their eyes perceive polarized light.

In 1969 and 1982, Ramscoe published books on the sun stone and Viking solar navigation (illustrations from nordskip.com).

Since light from the sky is also polarized according to the Rayleigh sky model, sailors could look up through the stone by slowly turning it in different directions.

The coincidence and non-coincidence of the polarization planes of the light scattered by the atmosphere and that of the crystal would be expressed in the form of a darkening and clearing of the sky as the stone and the observer turn around. A series of such successive "measurements" would help to find out with some decent accuracy where the Sun is.

Experts have put forward several candidates for the role of a sunstone - Icelandic spar (a transparent version of calcite), as well as tourmaline and iolite. It is difficult to say which mineral the Vikings used, all these stones were available to them.

Icelandic spar (left) and iolite (right, photographed from both sides to demonstrate strong pleochroism) have the right properties to try to learn how to navigate the hidden Sun.True, so far no one has conducted a convincing experiment with the stones themselves in the boundless sea in order to finally confirm the beautiful version of the ingenious navigation among the ancient Scandinavians (photos ArniEin/wikipedia.org, Gerdus Bronn).

It is curious that in the twentieth century, iolite found its way into aviation as a polarizing filter in an instrument used to determine the position of the Sun after sunset.

The fact is that even at twilight the glow of the sky is polarized, and therefore the exact direction to the hidden star can be easily recognized with "polaroid" vision. The reception will work even if the Sun has already dropped seven degrees below the horizon, that is, tens of minutes after sunset. By the way, bees are well aware of this fact, but we will return to them later.

In general terms, the principle of the Viking compass was clear for a long time, but the big question was the experimental verification of the idea. Gábor Horváth, a researcher from Otvos University in Budapest, has devoted the last few years to experiments and calculations in this direction.

In particular, together with colleagues from Spain, Sweden, Germany, Finland and Switzerland, he studied patterns of light polarization under cloudy skies (as well as in fog) in Tunisia, Hungary, Finland and within the Arctic Circle.

Gabor Horváth in the Arctic in 2005 (photo from elte.hu).

"Measurements were made using precise polarimeters," New Scientist informs. Now, Horvath et al. have summarized the results of the experiments.

In short: the original (from the so-called first-order scattering) pattern of polarization in the sky is still detectable even under the clouds, although it is very weak, and the cloudiness itself (or a foggy veil) introduces “noise” into it.

In both situations, the coincidence of the polarization pattern with the ideal one (according to the Rayleigh model) was the better, the thinner the cover of clouds or fog and the more breaks in it, supplying at least a fraction of direct sunlight.

The Arctic sky (from left to right) is hazy, clear and cloudy. From top to bottom: color image of the "dome", differences in the degree of linear polarization throughout the sky (darker - more), the measured angle of polarization and the theoretical angle with respect to the meridian. The last two rows show a good match (illustrated by Gábor Horváth et al./Philosophical Transactions of the Royal Society B).

Gabor and his associates also simulated navigation in conditions of a cloudy sky completely shrouded in a veil. It turned out that in this case, too, the "imprint" of the polarization is preserved and, theoretically, it is possible to calculate the position of the Sun from it. But the degree of polarization of the light in this case turned out to be very low.

In practice, this means that armed not with polarimeters, but with sunstones, the Vikings could hardly notice slight fluctuations in the brightness of the sky when looking through the crystal. Navigation under a continuous cloud cover, if possible, turned out to be inaccurate, the scientists concluded.

However, the investigation undertaken by Horvath showed that the legends about the sun stone and Thorkild's explanation of its work are quite plausible and scientifically sound.

Scientists have found that both in a clear sky (columns on the left) and in a cloudy sky (on the right), the proportion of the total sky area in which Rayleigh polarization (shaded in gray) falls as the Sun rises (black dot) above the horizon (elevation angle indicated in brackets). This photo was taken in Tunisia.

This, by the way, means that the “polarization” navigation method is more profitable in high latitudes, where the Vikings honed their skills (illustrations by Gábor Horváth et al. / Philosophical Transactions of the Royal Society B).

By the way, about the legends. Horvath quotes a reference to "polarizing navigation" in a Scandinavian saga: "The weather was cloudy, it was snowing. Saint Olaf, the king, sent someone to look around, but there was no clear dot in the sky. Then he asked Sigurd to tell him where the Sun was.

Sigurd took the sunstone, looked up at the sky and saw where the light came from. So he found out the position of the invisible Sun. It turned out that Sigurd was right.”

Nowadays, scientists describe the principle of navigation through polarized light much more accurately than the ancient storytellers. First, the birefringent crystal (the same sun stone) had to be “calibrated”. Looking at the sky through it in clear weather, and away from the luminary, the Viking had to turn the stone, achieving the greatest brightness. Then the direction to the Sun had to be scrawled on the stone.

The next time, as soon as a small gap appeared in the clouds, the navigator could aim a stone at it and turn it to the maximum brightness of the sky. The line on the stone would point to the Sun. We have already talked about determining the coordinates of a day star without any gap.

Archaeologists find sunken Viking ships from time to time, modern enthusiasts build copies of them (the video below shows one of these replicas - the ship Gaia), but so far not all the secrets of skilled sailors of the past have been revealed (illustrations from marineinsight.com, waterwaysnews.com, reefsafari.com.fj)

Well, it was easier to find out the direction to the geographical north by the position of the Sun. To do this, the Vikings had a specially marked sundial, on which the extreme trajectories of the shadow from the gnomon were shown by carvings (from dawn to sunset on the equinox and summer solstice).

If the Sun was present in the sky, the clock could be positioned in a certain way (so that the shadow fell on the desired band), and the cardinal directions could be determined from the marks on the disk.

The accuracy of these compass watches was great, but, with a correction: quite correctly they showed the north only from May to August (just in the Viking sailing season) and only at a latitude of 61 degrees - just where the most frequent route of the Vikings passed through the Atlantic between Scandinavia and Greenland (illustrations by Gábor Horváth et al./Philosophical Transactions of the Royal Society B).

Opponents of the theory of "polarimetric navigation" often say that even in cloudy and foggy weather, as a rule, the position of the Sun can be estimated by eye - according to the general picture of illumination, rays breaking through irregularities in the shroud, reflections on the clouds. And because, allegedly, the Vikings did not need to invent a complex method with a sun stone.

Gabor decided to test this assumption as well. He photographed many full panoramas of the daytime sky with cloudiness of varying severity, as well as the evening sky at dusk (near the sea horizon) at several points in the world. Then these pictures were shown to a group of volunteers - on a monitor in a dark room. They were asked with a mouse to indicate the location of the Sun.

One of the shots used in the eyeball navigation test. The subjects' attempts are shown by small white dots, a large black dot with a white edging marks the "average" position of the luminary according to observers (illustration by Gábor Horváth et al./Philosophical Transactions of the Royal Society B).

Comparing the choice of subjects with the actual location of the luminary, the scientists found that as the density of clouds increases, the average discrepancy between the apparent and true position of the Sun increases markedly, so the Vikings may well have needed additional technology for orientation to the cardinal points.

And to this argument it is worth adding one more. A number of insects are sensitive to linear polarization of light and use this advantage for navigation (and other crustaceans even recognize light with circular polarization). It is unlikely that evolution would have invented such a mechanism if the position of the Sun in the sky could always be seen with ordinary vision.

Biologists know that bees, with the help of polarized light, orient themselves in space - they look at gaps in the clouds. By the way, Horvath also recalls this example when he talks about the prerequisites for unusual navigation among the Vikings.

There is even a species of bees ( Magaloptagenalis from the halictid family), whose representatives even fly to work an hour before sunrise (and manage to return home before it) and then after sunset. These bees orient themselves in the twilight according to the polarization pattern in the sky. It is created by the Sun, which is just about to rise or has recently set.

For a long time, scientists could not understand how the Vikings traveled from Scandinavia by sea, overcoming thousands of nautical miles. It is known that they were excellent navigators and in the 9th-11th centuries they sailed to Russia and Ireland, and in the 10th century they discovered Greenland. However, how did they navigate, overcoming such great distances, if the compass was discovered only in the 16th century?

The sagas and legends speak of "sun stones" that were used for navigation even in bad weather - the stones helped them find the sun in the sky, even if it was completely covered by clouds. In particular, this is mentioned in the saga about the settlement of Greenland from the biography of King Olaf, who ruled Norway in the late 900s. It is interesting that in 1948 a copy of the Uunartok disk was found, which, in combination with the same solar stone (Solstenen), could serve for navigation. According to scientists, the device was a sundial marked with the cardinal points and carved, indicating a change in the shadow.

The first to suggest that such stones really existed was the Danish archaeologist Torvild Ramsku. In 1969, he stated that it could be a natural crystal that polarizes light (for example, calcite). In the process of observing the cloudy areas of the sky, by rotating the crystal, it was possible to find those areas from which, due to Rayleigh scattering, completely polarized light comes out. When drawing perpendiculars to the line that connects these areas, you can find the sun hidden behind the clouds, knowing its exact position.

Archaeologist Gabor Horváth and his colleagues have made computer simulations of Viking voyages from Bergen in Norway to Hvarf on the southern coast of Greenland, which took about three weeks. The model took into account 1000 such trips and the use of calcite (as well as cordierite, tourmaline and aquamarine) for navigation - an error was indicated for each stone. The journey began at the summer solstice or spring equinox, the cloudiness was set randomly. The model showed a very high probability of success of this method of navigation - 92%. However, this indicator was valid only if the stone was verified every 3 hours - with a course correction every 4 hours, the probability of success dropped to 32-58%, for verification every 6 hours - up to 10%. Scientists have suggested that it was an error in navigation that led the Vikings to land on the coast of Newfoundland in North America (the territory of modern Canada) in 985-1000. Later they founded the settlement of Vinland there. One way or another, the Vikings discovered North America and explored its territory long before the voyages of Christopher Columbus.

Although the theory that calcite was the same “sun stone” has not been proven (it was not found either in their graves or in the places where the settlements were located), this assumption well explains the navigational abilities of ancient sailors. Moreover, calcite was found among the tools on the British shipwreck in 1592, and there is evidence of the use of polarizing stones by pilots in the 20th century, when the compass could malfunction.

The way the ancient inhabitants of Scandinavia, the Vikings, oriented themselves in the open sea, in high latitudes, where the sun does not set below the horizon for months during the polar day, has long been a subject of conjecture, scientific disputes and assumptions, as well as folklore. And indeed, how, without a magnetic compass, without other navigational instruments, without the ability to navigate by the stars, which, for example, Arab or European sailors had, it was possible not only to discover new lands, but also to return back to the harsh, but such a beloved homeland , even after wintering in foreign lands?

Recent discoveries, coupled with research and experiments by scientists, show that the Vikings most likely used a sundial and a "sun stone" for orientation in their campaigns.

Mysterious Artifact

In 1948, in the ruins of a Benedictine monastery in Uunartok (Greenland), archaeologists discovered a mysterious wooden artifact. The area of ​​Uunartok was inhabited by the Vikings until the 10th century. The semicircular artifact had a zigzag engraving in the form of notches along the perimeter. If a symmetrical second part is attached to the artifact, then there would be exactly thirty-two of these cutouts, which coincides with the number of divisions on a modern compass, points. A few more lines were scrawled inside.

Some skeptics argue that this is just a household decoration, but most researchers think that this is the notorious Viking sun compass. The latter even tested its action on board an exact copy of the Viking ship. However, the navigation lines were incomplete and the instrument was therefore not very suitable for determining north. Without going into technical details, we can say that the error in this case was significant and would lead to a long voyage in the wrong direction, which in the conditions of the northern seas is not only dangerous, but deadly.

Scientists from the University of Budapest, led by Bernat Balasz, put forward their hypothesis that the find had a more complex structure and only in this form could it be successfully used for navigation. In their opinion, the design consisted of two gnomons (a part of a sundial, by the shadow from which the time is determined). The first, shorter and wider gnomon, served to determine half a day. The second, higher and narrower, and also more accurate, made it possible to determine the latitude. A similar, more complex device could already be used in the afternoon.

The alleged device of the Viking navigation device based on the found fragment. The lines were used for the rectangular gnomon (center), making it possible to fix the moment of local noon. Seventeen notches in the form of teeth on the (presumably) northern side served to read the length of the noon shadow of a tall gnomon. (Reconstruction of Balazs Bernath)

But what about orientation on cloudy days or after sunset? How did the Vikings navigate the northern latitudes so confidently and well that they were able to reach Greenland, discover America several centuries before Columbus, visit Baghdad, and, according to some sources, even the Far East?