четверг, 23 августа 2018 г.

The Whole Tooth Trainee dentists need plenty of practice but…

The Whole Tooth

Trainee dentists need plenty of practice but getting hold of real teeth for training purposes can be difficult. What’s more, using extracted natural teeth poses a risk of infection, and there can be wide variations in shapes and sizes. Although artificial teeth are available, made from various coloured resins that represent different components such as pulp or root, they don’t behave in the same way as genuine gnashers and aren’t well liked by students. Researchers are now developing ways of turning real-life imaging data from CT scans into lifelike 3D printed models like the one here, which are designed to more accurately reflect the structure, composition and properties of natural teeth. There’s more work to be done to develop the technique but given that nearly two thirds of dental procedures done by undergraduate trainees fail because they’ve had to learn with artificial teeth, let’s hope that they make it snappy.

Written by Kat Arney

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Culsh Earth House, Aberdeenshire, Scotland, 17.8.18.When I visited here last time in June...

Culsh Earth House, Aberdeenshire, Scotland, 17.8.18.

When I visited here last time in June this year, the entrance was home to a wasp’s nest. Now in mid August it has gone and this made it much easier to photograph the site. The earth house is in excellent condition and would have been used for storage for an Iron Age Roundhouse community.

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Comet 21P Approaching North America Nebula

At the time of writing Comet 21P/Giacobini-Zinner passed 58 Cygni (Latin v Cygni) a binary star in Cygnus which shines at magnitude 3.94 and 6.40. This means the comet is fast approaching the Mexico region of the North America nebula (NGC 7000) making for a good photographic opportunity.

This news comes with a sting in its tail for those located at higher latitudes however. As we have almost reached the Summer Solstice, those located above 50 deg N latitude will have far from ideal sky conditions. The Sun will not sink far below the horizon all night meaning that astronomical darkness is never reached. Those of you located in the UK and northern Europe, Canada or the northern states of the USA will have to battle with twilight. Not ideal for an object such as the North American nebula which requires a decent amount of exposure time to reveal good detail. 

Comet 21P will enter the boundary of the nebula around the 17 June and will pass 3rd magnitude star ξ Cygni on the night of 19-20 June leaving the nebula’s boundary a day later. Below is a finder chart for this time period.


Comet 21P and NGC7000

21p NGC7000 Finder Chart  21p NGC7000 Finder Chart

Click images to enlarge

The short period comet will brighten rapidly through July and August and is hoped to possibly reach naked eye visibility.  As night-time darkness conditions improve, 21p remains well placed for observation for most of the summer visible in the late evenings. The comet reaches perihelion on 10 September 2018 at a distance of 0.39 au from the Sun.

The post Comet 21P Approaching North America Nebula appeared first on Comet Watch.

Cullerlie Stone Circle, Aberdeenshire, Scotland, 17.8.18.A restored and reset stone...

Cullerlie Stone Circle, Aberdeenshire, Scotland, 17.8.18.

A restored and reset stone circle with multiple ring cairn settings.

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2018 August 23 Comet, Heart and Soul Image Credit &…

2018 August 23

Comet, Heart and Soul
Image Credit & Copyright: Juan Carlos Casado (TWAN, Earth and Stars)

Explanation: The greenish coma of comet 21P/Giacobini-Zinner stands out at the left of this telephoto skyscape spanning over 10 degrees toward the northern constellations Cassiopeia and Perseus. Captured on August 17, the periodic comet is the known parent body of the upcoming Draconid meteor shower. Predicted to be at its brightest next month, the comet is actually in the foreground of the rich starfield, only about 4 light-minutes from our fair planet. Giacobini-Zinner should remain too faint for your eye to see though, like the colorful Heart and Soul nebulae near the center of the sensitive digital camera’s field of view. But the pair of open star clusters at the right, h and Chi Persei, could just be seen by the unaided eye from dark locations. The Heart and Soul nebulae with their own embedded clusters of young stars a million or so years old, are each over 200 light-years across and 6 to 7 thousand light-years away. They are part of a large, active star forming complex sprawling along the Perseus spiral arm of our Milky Way Galaxy. Also known as the Double Cluster, h and Chi Persei are located at about that same distance. Periodic Giacobini-Zinner was visited by a spacecraft from Earth when the repurposed International Cometary Explorer passed through its tail in September 1985.

∞ Source: apod.nasa.gov/apod/ap180823.html

Carlungie Earth House Photoset 1, nr. Dundee, Scotland, 16.8.18.A sophisticated network...

Carlungie Earth House Photoset 1, nr. Dundee, Scotland, 16.8.18.

A sophisticated network of semi-subterranean passages and roundhouse foundations from the Iron Age.

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10 Things: How to Photograph a Meteor Shower

Taking photographs of a meteor shower can be an exercise in patience as meteors streak across the sky quickly and unannounced, but with these tips – and some good fortune – you might be rewarded with a great photo.

These tips are meant for a DSLR or mirrorless camera, but some point-and-shoot cameras with manual controls could be used as well.

1. The Photo Op: Perseids Meteors

The Perseids are dusty remnants of comet 109P/Swift-Tuttle.

Earth passes through the comet’s invisible, multi-billion mile trail of tiny debris each year around August, creating a meteor shower of so-called “shooting stars” as the particles are vaporized in our atmosphere.

Perseid meteors already are streaking across the sky. This year’s shower peaks on a moonless summer night -from 4 pm on the 12th until 4 am on the 13th Eastern Daylight Time.

Read more on the Perseids

2. Get away from city lights and find a place with dark skies.

In this 30 second exposure, a meteor streaks across the sky in Spruce Knob, West Virginia, during the 2016 Perseids meteor shower. Credit: NASA/Bill Ingalls

Too much light and it will be hard for your eyes to see fainter meteors, plus your image will get flooded with the glow of light. Turning down the brightness of the camera’s LCD screen will help keep your eyes adjusted to the dark. The peak of the 2018 Perseid meteor shower occurs just after the new moon, meaning a thin crescent will set long before the best viewing hours, leaving hopeful sky watchers with a moonlight-free sky!

3. Use a tripod.

In this ten-second exposure, a meteor streaks across the sky above Washington, DC during the 2015 Perseids meteor shower, Credit: NASA/Joel Kowsky

Meteor photography requires long exposures, and even the steadiest of hands can’t hold a camera still enough for a clear shot. Heavier tripods help reduce shaking caused by wind and footsteps, but even a lightweight tripod will do. You can always place sandbags against the feet of the tripod to add weight and stability. If you don’t have a tripod, you might be able to prop your camera on or up against something around you, but be sure to secure your camera.

4. Use a wide-angle lens.

In this 30 second exposure taken with a circular fish-eye lens, a meteor streaks across the sky during the 2016 Perseids meteor shower as a photographer wipes moisture from the camera lens Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls

A wide-angle lens will capture more of the sky and give you a greater chance of capturing a meteor in your shot, while a zoom lens captures a smaller area of the sky. The odds of a meteor streaking past that small patch are lower.

5. Use a shutter release cable or the camera’s built-in timer.

Long exposures are not just for meteors. In this shot taken at Joshua Tree National Park, a hiker’s headlamp leaves a trail of light along a twilight path. Credit: National Park Service / Hannah Schwalbe

A tripod does a great job of reducing most of the shaking your camera experiences, but even the act of pressing the shutter button can blur your extended exposure. Using the self-timer gives you several seconds for any shaking from pressing the shutter button to stop before the shutter is released. A shutter release cable (without a self-timer) eliminates the need to touch the camera at all. And if your camera has wifi capabilities, you might be able to activate the shutter from a mobile device.

6. Manually focus your lens.

In this 30 second exposure, a meteor streaks across the sky during the annual Perseids meteor shower Friday, August 12, 2016 in Spruce Knob, West Virginia. Credit: NASA/Bill Ingalls

At night, autofocus will struggle to find something on which to focus. Setting your focus to infinity will get you close, but chances are you’ll have to take some test images and do some fine tuning. With your camera on a tripod, take a test image lasting a few seconds, then use the camera’s screen to review the image. Zoom in to a star to see how sharp your focus is. If the stars look like fuzzy blobs, make tiny adjustments to the focus and take another test image.

Repeat until you are happy with the result.

If your camera has a zoomable electronic viewfinder or live view option, you might be able to zoom to a star and focus without having to take a test image.

7. Aim your camera.

The Perseids appear to radiate from the constellation Perseus, visible in the northern sky soon after sunset this time of year.

Even though we don’t know when or where a single meteor will appear, we do know the general area from which they’ll originate.

Meteor showers get their name based on the point in the sky from which they appear to radiate. In the case of the Perseids, during their peak, they appear to come from the direction of the constellation Perseus in the northern sky.

8. Calculate your exposure time.

In this 20-second exposure, a meteor lights up the sky over the top of a mountain ridge near Park City, Utah. Even though this image was captured during the annual Perseid meteor shower, this “shooting star” is probably not one of the Perseid meteors, which originate from material left behind by Comet Swift-Tuttle. Instead, it’s likely one of the many bits of rock and dust that randomly fall into the atmosphere on any given night. Credit: NASA/Bill Dunford

As Earth rotates, the stars in the sky appear to move, and if your shutter is open long enough, you might capture some of that movement. If you want to avoid apparent star movement, you can follow the 500 Rule. Take 500 and divide it by the length in millimeters of your lens. The resulting number is the length of time in seconds that you can keep your shutter open before seeing star trails. For example, if you’re using a 20 mm lens, 25 seconds (500 divided by 20) is the longest you can set your exposure time before star trails start to show up in your images.

9. Experiment!

In this 30 second exposure photo, hikers find their way to the top of Spruce Knob in West Virginia to view the annual Perseids meteor shower, Friday, August 12, 2016. Credit: NASA/Bill Ingalls

Once you know the maximum exposure time, you can set your shutter priority to that length and let the camera calculate other settings for your first image. Depending on how the image turns out, you can manually adjust aperture (set it to a lower number if the image is too dark) and ISO (set it to a higher number if the image is too dark) to improve your next images. Changing only one setting at a time will give you a better understanding of how those changes affect your image.

10. Enjoy the show.

The crew of the International Space Station captured this Perseid meteor falling to Earth over China in 2011. Credit: NASA

With your camera settings adjusted, capturing that perfect photo is just a matter of time and luck. The highest rate of meteors visible per hour is in the hours after midnight and before dawn. Set up your camera next to a lounge chair or a blanket to witness the wonder of a meteor shower for yourself – and, with any luck, you’ll take home some envy-inducing shots, too!

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ESA’s Aeolus Wind Satellite Launched

ARIANESPACE – Vega Flight VV12 Aeolus Mission poster.

23 August 2018

Image above: Vega lifts off on Arianespace’s fifth mission of 2018 from the Spaceport in French Guiana. Flight VV12 Aeolus.

ESA’s Earth Explorer Aeolus satellite has been launched into polar orbit on a Vega rocket. Using revolutionary laser technology, Aeolus will measure winds around the globe and play a key role in our quest to better understand the workings of our atmosphere. Importantly, this novel mission will also improve weather forecasting.

Aeolus liftoff replay

Carrying the 1360 kg Aeolus satellite, the Vega rocket lifted off from Europe’s Spaceport in Kourou, French Guiana, at 21:20 GMT (23:20 CEST, 18:20 local time) on 22 August. Some 55 minutes later, Vega’s upper stage delivered Aeolus into orbit and contact was established through the Troll ground station in Antarctica at 00:30 CEST on 23 August.

Named after Aeolus, who in Greek mythology was appointed ‘keeper of the winds’ by the Gods, this novel mission is the fifth in the family of ESA’s Earth Explorers, which address the most urgent Earth-science questions of our time.

Aeolus satellite

“Aeolus epitomises the essence of an Earth Explorer. It will fill a gap in our knowledge of how the planet functions and demonstrate how cutting-edge technology can be used in space,” said Jan Wörner, ESA Director General.

ESA’s Director of Earth Observation Programmes, Josef Aschbacher, added, “Aeolus carries the first instrument of its kind and uses a completely new approach to measuring the wind from space.

Aeolus reveals all

“Such pioneering technology has meant that it has been a demanding mission to develop, but thanks to all the teams involved we are thrilled that this extraordinary satellite is now in orbit. We look forward to it living up to expectations!”

Highlighted by the World Meteorological Organization, the lack of direct global wind measurements is one of the major deficits in the Global Observing System.

By filling this gap, Aeolus will give scientists the information they need to understand how wind, pressure, temperature and humidity are interlinked.

This new mission will provide insight into how the wind influences the exchange of heat and moisture between Earth’s surface and the atmosphere – important aspects for understanding climate change.

Earth’s winds

Aeolus carries one of the most sophisticated instruments ever to be put into orbit. The first of its kind, the Aladin instrument includes revolutionary laser technology to generate pulses of ultraviolet light that are beamed down into the atmosphere to profile the world’s winds – a completely new approach to measuring the wind from space.

While Aeolus is set to advance science, it will also benefit society.

Although weather forecasts have advanced considerably in recent years, Aeolus will provide global wind profiles to improve the accuracy even further. In addition, its data will be used in air-quality models to improve forecasts of dust and other airborne particles that affect public health.

 Profiling the world’s winds

The satellite is being controlled from ESA’s European Space Operations Centre in Darmstadt, Germany. Controllers will spend the next few months carefully checking and calibrating the mission as part of its commissioning phase.

Related links:

Aeolus: http://www.esa.int/Our_Activities/Observing_the_Earth/Aeolus

Vega-C: http://www.esa.int/Our_Activities/Space_Transportation/Launch_vehicles/Vega-C

Europe’s Spaceport: http://www.esa.int/Our_Activities/Space_Transportation/Europe_s_Spaceport

Arianespace: http://www.arianespace.com/

CNES: https://cnes.fr/en

Airbus Defence and Space: http://www.airbus.com/

Centre Spatial de Liège: http://www.csl.uliege.be/jcms/c_5053/en/home

Images, Video, Text, Credits: ESA/Arianespace /ATG medialab.

Best regards, Orbiter.chArchive link

Nice sunny days can grow into heat waves… and wildfires: summer weather is stalling

Be it heavy downpours or super-hot spells, summer weather becomes more persistent in North America, Europe and parts of Asia. When those conditions stall for several days or weeks, they can turn into extremes: heatwaves resulting in droughts, health risks and wildfires; or relentless rainfall resulting in floods. A team of scientists now presents the first comprehensive review of research on summer weather stalling focusing on the influence of the disproportionally strong warming of the Arctic as caused by greenhouse-gas emissions from burning fossil fuels. Evidence is mounting, they show, that we likely meddle with circulation patterns high up in the sky. These are affecting, in turn, regional and local weather patterns — with sometimes disastrous effects on the ground. This has been the case with the 2016 wildfire in Canada, another team of scientists show in a second study.

Nice sunny days can grow into heat waves... and wildfires: summer weather is stalling
Credit: EPA, CC BY-SA

“Giant airstreams encircle our globe in the upper troposphere — we call them planetary waves,” explains Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research (PIK) and co-author of the second paper. “Now evidence is mounting that humanity is messing with these enormous winds. Fueled by human-made greenhouse-gas emissions, global warming is probably distorting the natural patterns.” Usually the waves, conveying chains of high- and low-pressure domains, travel eastwards between the equator and the North Pole. “Yet when they get trapped due to a subtle resonance mechanism,” says Schellnhuber, “they slow down so the weather in a given region gets stuck. Rains can grow into floods, sunny days into heat waves, and tinder-dry conditions into wildfires.”

Investigating the Arctic Factor and connecting the dots

“While it might not sound so bad to have more prolonged sunny episodes in summer, this is in fact a major climate risk,” says Dim Coumou from the Potsdam Institute for Climate Impact Research (PIK) and Vrije Universiteit Amsterdam, lead-author of the review paper and co-author of the wildfire case study. “We have rising temperatures due to human-caused global warming which intensifies heat waves and heavy rainfall, and on top of that we could get dynamical changes that make weather extremes even stronger — this is quite worrying.” This summer is an impressive example of how stalling weather can impact societies: persistent hot and dry conditions in Western Europe, Russia and parts of the US threaten cereal yields in these breadbaskets.

Tons of studies have appeared on this topic in recent years, sometimes with seemingly conflicting results. For the paper now published in Nature Communications, an international team of scientists set out to review the existing research and tried to connect the dots, with a focus on the Arctic factor. Under global warming, the Arctic warms more than the rest of the Northern hemisphere. This reduces the temperature difference between the North Pole and the equator, yet this very difference is a main driving force for the airstreams. “There are many studies now, and they point to a number of factors that could contribute to increased airstream stalling in the mid-latitudes — besides Arctic warming, there’s also the possibility of climate-change-induced shifting of the storm tracks, as well as changes in the tropical monsoons,” says Simon Wang from Utah State University in the US, a co-author of the review paper.

Nice sunny days can grow into heat waves -- and wildfires: summer weather is stalling
Dynamical mechanisms which link Arctic Amplification with summer mid-latitude weather patterns
[Credit: Coumou et al, Nature Communications 2018]

“Under global warming, the Indian summer monsoon rainfall will likely intensify and this will also influence the global airstreams and might ultimately contribute to more stalling weather patterns. All of these mechanisms do not work in isolation but interact,” says Wang. “There is strong evidence that winds associated with summer weather systems are weakening and this can interact with so-called amplified quasi-stationary waves. These combined effects point towards more persistent weather patterns, and hence more extreme weather.”

The case of the Canadian wildfire disaster

The wildfire in Canada’s Alberta region in 2016 is one stark example for the potentially disastrous impact of planetary-waves slow-down and the resulting summer-weather stalling. In a study now published in Scientific Reports, the other research team shows that indeed the blaze has been preceded by the trapping of a specific kind of airstreams in the region. In combination with a very strong El-Nino event this favored unusually dry and high-temperature conditions on the ground, entailing an increased fire hazard here. It took two months before the officials eventually could declare the fire to be under control. This was the costliest disaster in Canadian history with total damages reaching 4.7 billion Canadian Dollars.

“Clearly, the planetary wave pattern wasn’t the only cause for the fire — yet it was an additional important factor triggering a deplorable disaster,” says Vladimir Petoukhov from PIK, lead-author of the case study. “In fact, our analysis reveals that beyond that single event, actually from the 1980s on, planetary waves were a significant factor for wildfire risks in the region. Since it is possible to detect the wave patterns with a relatively long lead-time of ten days, we hope that our findings can help forest managers and fire forecasters in the future.”

A phenomenon that sounds funny but isn’t: “extreme extremes”

“Computer simulations generally support the observations and our theoretical understanding of the processes, so this seems pretty robust,” concludes Coumou. “However, the observed changes are typically more pronounced than those seen in climate models.” So either the simulations are too conservative, or the observed changes are strongly influenced by natural variability. “Our review aims at identifying knowledge gaps and ways forward for future research,” says Coumou. “So there’s still a lot to do, including machine learning and the use of big data. While we do not have certainty, all in all the state of research indicates that changes in airstreams can, together with other factors, lead to a phenomenon that sounds funny but isn’t: extreme extremes.”

Source: Potsdam Institute for Climate Impact Research (PIK) [August 20, 2018]



Massive monumental cemetery built by Eastern Africa’s earliest herders discovered...

An international team, including researchers at Stony Brook University and the Max Planck Institute for the Science of Human History, has found the earliest and largest monumental cemetery in eastern Africa. The Lothagam North Pillar Site was built 5,000 years ago by early pastoralists living around Lake Turkana, Kenya. This group is believed to have had an egalitarian society, without a stratified social hierarchy. Thus their construction of such a large public project contradicts long-standing narratives about early complex societies, which suggest that a stratified social structure is necessary to enable the construction of large public buildings or monuments. The study, led by Elisabeth Hildebrand, of Stony Brook University, is published in the Proceedings of the National Academy of Sciences.

Massive monumental cemetery built by Eastern Africa's earliest herders discovered in Kenya
Stone pendants and earrings from the communal cemetery of Lothagam North, Kenya, built by eastern Africa’s
earliest herders ~5000-4300 years ago. Megaliths, stone circles, and cairns flank the 30-m platform mound; its
 mortuary cavity contains an estimated several hundred individuals, tightly arranged. Most burials had highly
personalized ornaments. Lothagam North demonstrates monumentality may arise among dispersed,
mobile groups without strong hierarchy [Credit: Carla Klehm]

The Lothagam North Pillar Site was a communal cemetery constructed and used over a period of several centuries, between about 5,000 and 4,300 years ago. Early herders built a platform approximately 30 meters in diameter and excavated a large cavity in the center to bury their dead. After the cavity was filled and capped with stones, the builders placed large, megalith pillars, some sourced from as much as a kilometer away, on top.

Stone circles and cairns were added nearby. An estimated minimum of 580 individuals were densely buried within the central platform cavity of the site. Men, women, and children of different ages, from infants to the elderly, were all buried in the same area, without any particular burials being singled out with special treatment.

Additionally, essentially all individuals were buried with personal ornaments and the distribution of ornaments was approximately equal throughout the cemetery. These factors indicate a relatively egalitarian society without strong social stratification.

Historically, archaeologists have theorized that people built permanent monuments as reminders of shared history, ideals and culture, when they had established a settled, socially stratified agriculture society with abundant resources and strong leadership.

Massive monumental cemetery built by Eastern Africa's earliest herders discovered in Kenya
View of Lothagam North Pillar Kenya, built by eastern Africa’s earliest herders ~5000-4300 years ago. Megaliths, stone
circles, and cairns can be seen behind the 30-m platform mound; its mortuary cavity contains an estimated several
hundred individuals, tightly arranged. Most burials had highly personalized ornaments. Lothagam North
demonstrates monumentality may arise among dispersed, mobile groups without strong hierarchy
[Credit: Katherine Grillo]

It was believed that a political structure and the resources for specialization were prerequisites to engaging in monument building. Ancient monuments have thus previously been regarded as reliable indicators of complex societies with differentiated social classes. However, the Lothagam North cemetery was constructed by mobile pastoralists who show no evidence of a rigid social hierarchy.

“This discovery challenges earlier ideas about monumentality,” explains Elizabeth Sawchuk of Stony Brook University and the Max Planck Institute for the Science of Human History. “Absent other evidence, Lothagam North provides an example of monumentality that is not demonstrably linked to the emergence of hierarchy, forcing us to consider other narratives of social change.”

The discovery is consistent with similar examples elsewhere in Africa and on other continents in which large, monumental structures have been built by groups thought to be egalitarian in their social organization.

This research has the potential to reshape global perspectives on how — and why — large groups of people come together to form complex societies. In this case, it appears that Lothagam North was built during a period of profound change. Pastoralism had just been introduced to the Turkana Basin and newcomers arriving with sheep, goats, and cattle would have encountered diverse groups of fisher-hunter-gatherers already living around the lake.

Massive monumental cemetery built by Eastern Africa's earliest herders discovered in Kenya
Stone palette with zoomorphic bovine carving from the communal cemetery of Lothagam North, Kenya, built by
eastern Africa’s earliest herders ~5000-4300 years ago. Megaliths, stone circles, and cairns flank the 30-m platform
 mound; its mortuary cavity contains an estimated several hundred individuals, tightly arranged. Most burials
 had highly personalized ornaments. Lothagam North demonstrates monumentality may arise among
dispersed, mobile groups without strong hierarchy [Credit: Katherine Grillo]

Additionally, newcomers and locals faced a difficult environmental situation, as annual rainfall decreased during this period and Lake Turkana shrunk by as much as fifty percent. Early herders may have constructed the cemetery as a place for people to come together to form and maintain social networks to cope with major economic and environmental change.

“The monuments may have served as a place for people to congregate, renew social ties, and reinforce community identity,” states Anneke Janzen also of the Max Planck Institute for the Science of Human History. “Information exchange and interaction through shared ritual may have helped mobile herders navigate a rapidly changing physical landscape.” After several centuries, pastoralism became entrenched and lake levels stabilized. It was around this time that the cemetery ceased to be used.

“The Lothagam North Pillar Site is the earliest known monumental site in eastern Africa, built by the region’s first herders,” states Hildebrand. “This finding makes us reconsider how we define social complexity, and the kinds of motives that lead groups of people to create public architecture.”

Source: Max Planck Institute for the Science of Human History [August 20, 2018]



Study shows indigenous Canadian Arctic people’s textiles predated European contact

A new study by Brown University researchers shows that the Dorset and Thule people—ancestors of today’s Inuit—created spun yarn some 500 to 1,000 years before Vikings arrived in North America. The finding, made possible in part by a new method for dating fiber artifacts contaminated with oil, is evidence of independent, homegrown indigenous fiber technology rather than a transfer of knowledge from Viking settlers.

Study shows indigenous Canadian Arctic people's textiles predated European contact
Example of Dorset culture spun yarn from the Nanook Site 
[Credit: Brown University]

The study was led by Michele Hayeur Smith, a research associate at Brown’s Haffenreffer Museum of Anthropology, who focused on artifacts from five Dorset and Thule archaeological sites in the eastern Canadian Arctic held in the Canadian Museum of History’s collections. Co-authored with Kevin P. Smith, deputy director and chief curator of the Haffenreffer Museum, and Gørill Nilsen of the Arctic University of Norway, the research is changing the understanding of indigenous textile technology as well as the nature of the contact between Dorset and Thule peoples and the earliest European explorers of the eastern Canadian Arctic.

Here, Hayeur Smith and Smith discuss the study, published in Journal of Archaeological Science, and what it means for understanding the history of the high Canadian Arctic.

Q: What was the impetus for undertaking this study?

Michele Hayeur Smith (MHS): I am a specialist in Norse textiles, and I was researching the production and circulation of textiles from the Viking age to the 19th century. I started this project because it came to my attention that there were huge collections of pre-modern textiles in Iceland, which is where I started out. I was also interested in looking at women. Textiles happen to be a very gendered activity in Norse society—men had no involvement whatsoever with it. In Iceland, it became very important because it was a form of currency for almost 800 years: Everything was based on the value of cloth.

I eventually expanded my research to the rest of the North Atlantic to see what was going on in the other Norse colonies in terms of textiles. There were some fragments of cloth and yarn that had been found in the Canadian High Arctic, and there was an assumption that it came from the Norse. I went through the collections at Canadian Museum of History—a sizeable collection of pieces of yarn that had been claimed to be Norse. The assumption was that Norse had taught the Inuit how to spin, that it was a cultural transfer.

Q: What did you discover?

MHS: I went in thinking it was an interesting hypothesis that there was a Norse trading post in Baffin Island. First, I performed an initial physical analysis of the material, which included spun sinew, spun yarn, woven textiles and raw wool of unknown species. Second, I needed to date it. And third, I got permission to sample the pieces and do some DNA analysis to identify the animal fibers in them.

One textile piece from the high north was Norse, and several others from a site called Okivilialuk were also clearly fragments of woven European cloth, but not Norse. However, strands of yarn from southern Baffin Island, at sites called Nanook, Nunguvik and Willows Island 4, were obviously different, and not Norse. This yarn, when I analyzed it, immediately struck me as distinct. The materials were wrong for Norse textiles, made of maybe musk ox or arctic hare rather than sheep or goat. The fibers were very tightly spun, very consistent, with very little variation in how it was made, which is not what you see in Norse textiles.

Study shows indigenous Canadian Arctic people's textiles predated European contact
Example of Dorset culture spun yarn from the Nanook Site 
[Credit: Brown University]

At that point, we worked with a commercial laboratory, Beta Analytic, using the protocol Gørill Nilsen developed, which is critical in accurately dating textiles contaminated with marine mammal oils. In the high Canadian Arctic, people live predominantly off marine mammals. They would hunt seals, whales and other animals and use the fats for a range of purposes. The oils from these mammals permeate archaeological sites and artifacts, including textiles. Because of what is known as the marine reservoir effect, in which sea mammals absorb ancient marine carbon, the radiocarbon date of artifacts with marine oil on them can be thrown off by 400 to 800 years. Nilsen’s method essentially “shampoos” out the oils so Beta Analytic could use Accelerator Mass Spectrometry (AMS) dating to give us an accurate age.

Q: And you used this new method to date the yarn and textile samples?

Kevin P. Smith (KPS): First, we tested Gørill’s method on two pieces of cloth—we split one piece of yarn and tested it without using her method. The date came back older than any known date for human occupation in the Arctic, so we knew it was contaminated; but after we used her method to clean the sample, we re-dated it and it fit other evidence from the site beautifully. Then we tested her method on another piece of cloth whose age we already knew and received an identical date. These tests showed us that the method could remove contaminants without damaging the cloth and affecting dates on it.

Then, we applied her method to one piece of spun sinew and seven pieces of spun yarn from Dorset culture sites, to one piece of Norse textile from an ancestral Inuit, Thule culture site, and to two of those mysterious pieces of European cloth from Okivilialuk.

Q: What did the AMS date tell you about the yarn and textile samples?

KPS: The results were jaw-dropping.

The oldest Dorset pieces were made almost 1,000 years before the Vikings settled in Greenland, around 1000 AD. In fact, the oldest piece of yarn, from a site on Willows Island, was dated to between 15 B.C. and 50 A.D. And the most recent piece of Dorset culture yarn was spun around 725 A.D. We knew then that the Dorset had been spinning yarn for more than a thousand years before the Vikings arrived in Greenland and was a consistent part of their culture for at least 800 years! It’s also interesting that there appears to be no evidence that the Dorset people shared this technology with the Thule people, ancestors of today’s Inuit, who migrated across the Canadian Arctic and eventually to Greenland, in the late 1200s A.D.

Study shows indigenous Canadian Arctic people's textiles predated European contact
Michele Hayeur Smith’s research on textiles spanning the North Atlantic region has been supported
 by three major grants from the National Science Foundation’s Arctic Social Science Program
[Credit: Brown University]

However, when we turned to the piece of woven cloth from an ancestral Inuit site called Skraeling Island, we confirmed that those Thule ancestors of today’s Inuit were in contact with Norse explorers in the High Arctic during the late around 1275 A.D., almost 300 years after the Vikings had tried, unsuccessfully, to establish a colony in North America.

Finally, those pieces from Okivilialuk were both woven in the 1500s, suggesting that the Inuit there were in contact with some of the earliest post-medieval explorers of the Arctic, including Martin Frobisher [an English navigator who reached Labrador and Baffin Island in 1576].

Q: In the study, you note that archaeologists have been somewhat reluctant to acknowledge the possibility of an indigenous fiber technology. Why do you think that is?

MHS: I would say that the assumption that indigenous people did not know how to spin is ethnocentric. This is a problem in our field. The sewing skills and abilities of Arctic peoples is unbelievable. They are able to stitch garments made out of gut that are entirely waterproof because the stitching they’re using is so sealed and so tight. If you’re already spinning sinew because you’re making thread out of it, and you happen to come across a piece of musk ox hair on the ground, you know how to spin. It’s a very intuitive technique. I’ve also seen baskets made with Thule material. If you know how to make baskets, you know how to weave. Why is the idea of indigenous fiber technology shocking, surprising people so much? I don’t know.

Q: What other questions do your findings raise?

KPS: One of the big questions that it raises is, what is the fiber technology of the Dorset? It also shows that the history of contact between various Indigenous cultures of the North (the Dorset and the Thule) with one another and with different European explorers was more complex than expected—and can be unraveled with such unexpected artifacts as yarn and cloth. But I think the most important finding is that the analyses document nearly 1,500 years of creativity, innovation, selective acquisition and use of textiles by the Indigenous people of the Arctic rather than forcing us to believe that spinning yarn and other cultural changes in the North required a brief period of technological transfer from Europeans.

Source: Brown University [August 21, 2018]




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