Waun Maun was an ancient Welsh stone circle that had an awful lot in common with Stonehenge.
A mystery of dates solved<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTY1MzI4Mi9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1NTE4Nzk2OX0.7m_x0Sf1EGBnHt-pDD7C8SOnYZpKzOZlqlb8fEeJL6E/img.png?width=980" id="5a9f5" class="rm-shortcode" data-rm-shortcode-id="8f5585b5f6689d90fc94d20398aa1ac8" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: Ankit Sood/Unsplash<p>The theory has to do with Stonehenge's bluestones. These are the 43 smaller upright stones positioned at the inside of the structure. They're called "bluestones" not because they're normally blue, but because they take on a bit of that hue when they're wet. (The outer, taller, stones at Stonehenge are sarsens, and the stones laying across the tops of other stones are its lintel stones.)</p><p>It has been known for some time that the bluestones were dug from a quarry in the Preseli Hills of Wales 200 km away some 5,000 years ago. (The larger <a href="https://bigthink.com/culture-religion/stonehenge-sarsens" target="_blank">sarsen stones </a>are believed to have come from about 15 miles away from Stonehenge.)</p><p>There's been a problem with dates, though. The rocks were extracted about 5,000 years ago, between 3400 BC and 3000 BC. That's 300 or 400 years before Stonehenge was built. Where were they all that time? "They're clearly not spending 200 years slowly moving them across the landscape," co-author of the research <a href="https://www.southampton.ac.uk/archaeology/about/staff/cjp1r10.page" target="_blank">Joshua Pollard</a> tells <a href="https://www.sciencemag.org/news/2021/02/england-s-stonehenge-was-erected-wales-first" target="_blank" rel="noopener noreferrer">Science Magazine</a>.</p><p>The earliest writing about the origins of Stonehenge was Geoffrey of Monmouth's c. AD 1136 "History of the Kings of Britain." In it, the author suggests that Stonehenge was constructed from the stones of a dismantled Giants' Dance stone circle atop the mythical Mount Killaraus, having been moved to Salisbury under the command of Merlin. Fantasy, to be sure, but the distant origin of the bluestones may underpin the central idea that these stones were actually repurposed from another place and time.</p>
Waun Mawn<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTY1MzMwNS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxNjM4NjE5N30.esfI2abeHi5BZbt_MEXRc3yYcNR-wgV9ZuvB6wdGPK0/img.png?width=980" id="78345" class="rm-shortcode" data-rm-shortcode-id="3e84e01b24068eadc6a19b140726320e" data-rm-shortcode-name="rebelmouse-image" data-width="898" data-height="1000" />
Credit: Denys Holovatiuk/Adobe Stock/Big Think<p>The "<a href="https://www.english-heritage.org.uk/visit/places/stonehenge/things-to-do/stone-circle/stones-of-stonehenge/" target="_blank">Stones of Stonehenge</a>" project identified a possible Welsh stone circle in 2010, Waun Mawn, but had not excavated it. In 2017 and 2018, a research team led by Parker Pearson began serious exploration. They identified an ancient megalith quarry nearby and the toppled bluestone remains of the stone circle, estimated to be the third largest yet found after Avebury in Wiltshire and Stanton Drew in Somerset.</p><p>At Waun Mawn were socket-shaped pits that likely held other, long-gone bluestones. The researchers used optically simulated luminescence to determine how long ago the sediments buried inside the pits had been exposed to light, and radiocarbon-dated charcoal found inside. The shrine dates back pretty perfectly to 3400 BC, in line with the time the bluestones had been quarried.</p><p>The researchers mapped out the likely arrangement of the stone circle by extrapolating between the remaining stones and empty stone sockets. They arrived at a shape that measured about 100 meters across, the same as Stonehenge's original layout, the ditch currently surrounding it. (Stonehenge has been rearranged many times since it was first built.) Waun Mawn, like Stonehenge, was aligned on the midsummer solstice.</p><p>The researchers estimate that the missing bluestones were removed between 300 and 400 years after the stone circle was built, around the time Stonehenge was built. "We're quite confident the reason they come down is they've gone to Stonehenge," Parker Pearson tells <a href="https://www.sciencemag.org/news/2021/02/england-s-stonehenge-was-erected-wales-first" target="_blank">Science Magazine</a>.</p><p>Other clues? One of the Stonehenge bluestones has an unusual shape that matches one of the Waun Mawn pits perfectly. In addition, sone chips found in that pit precisely match that stone at Stonehenge.</p>
There goes the neighborhood<p>Sometime after 3000 BC, the people living near Waun Maun left — there's little evidence of habitation in the area after about 3400 BC, according to Parker Pearson. "It's as if they just vanished," he says. "Maybe most of the people migrated, taking their stones — their ancestral identities — with them, to start again in this other special place. This extraordinary event may also have served to unite the peoples of east and west Britain."</p><p>Analyses of plant and animal remains at Stonehenge indicate that the people who built it spent their early years on the Welsh coast, providing evidence, says Pollard, that "We've got regular contact between the two regions."</p><p>Parker Pearson suggests that maybe the people who built Stonehenge incorporated the bluestones from Waun Mawn for one of two reasons: to have something of their former home in their new one, or to use the bluestones as symbols of their authority, thus entitling it to respect and power among their new neighbors.</p><p>In any event, Pearson suspects there's more to the story. Waun Mawn's stones may not be the only transplants at Stonehenge:</p><p style="margin-left: 20px;">"With an estimated 80 bluestones put up on Salisbury Plain at Stonehenge and nearby Bluestonehenge, my guess is that Waun Mawn was not the only stone circle that contributed to Stonehenge. Maybe there are more in Preseli waiting to be found. Who knows? Someone might be lucky enough to find them."</p>
A new model of plate tectonics offers a chance to look back a billion years with new found accuracy.
- A new way of looking at plate tectonics offers evidence for how the world looked up to a billion years ago.
- By focusing on plate boundaries rather than the continents and land itself, it avoids the pitfalls of other methods.
- The model doesn't account for everything but is still a great step forward in our understanding of continental drift.
So what does this new approach provide us?<video controls id="99760" width="100%" class="rm-shortcode" data-rm-shortcode-id="93a975ab78f5e959c6095c99743995e1" expand="1" feedbacks="true" mime_type="video/mp4" shortcode_id="1613057169772" url="https://roar-assets-auto.rbl.ms/runner%2F22367-ezgif.com-gif-maker.mp4" videoControls="true"> <source src="https://roar-assets-auto.rbl.ms/runner%2F22367-ezgif.com-gif-maker.mp4" type="video/mp4"> Your browser does not support the video tag. </video><p> Instead of looking at continents themselves, this approach focuses on how the boundaries between plates move over time. This avoids the limitations of other methods, as the records of where plate boundaries were located are quite enduring. </p><p>Louis Moresi, a geologist at the Australian National University who was not involved with this study, explained the concept, which he called "astonishing" to <a href="https://cosmosmagazine.com/earth/earth-sciences/tectonic-timelapse/" target="_blank" rel="noopener noreferrer">Cosmos Magazine</a>:</p><p>"The plates are continually shoving the continents around and crashing them into each other. That means the geological record is full of evidence of old plate boundaries and the past actions of plates. We have billions of years of the continental record – for example, old mountain belts leave traces in the rock and sedimentary record even after being eroded – so we have evidence for plates from a billion years ago even though they are long gone into the mantle."</p><p>Understanding where the plates were at what times can shed light on the long distant past and explain why the world is the way it is <a href="https://www.nytimes.com/2021/02/06/science/tectonic-plates-continental-drift.html" target="_blank">today</a>. </p><p>For example, the <a href="https://en.wikipedia.org/wiki/Snowball_Earth" target="_blank" rel="noopener noreferrer">Snowball Earth hypothesis</a>, the proposal that most of the Earth's surface was frozen over at one or a few points, is relatively dependent on where the continents were at various times. If the continents were not in the correct <a href="https://en.wikipedia.org/wiki/Snowball_Earth#Continental_distribution" target="_blank" rel="noopener noreferrer">locations</a>, the possibility of the Snowball occurrence lowers considerably. This new technique allows scientists to estimate where continents were at those times with more confidence than before.</p><p>This model may also be of use in figuring out how and when oxygen became such an important part of the atmosphere, which in turn made life like us <a href="https://phys.org/news/2021-02-video-billion-years-seconds.html" target="_blank" rel="noopener noreferrer">possible</a>.</p><p>This isn't the end-all solution to everything though, as the authors admit in their study, it doesn't consider things like "<a href="https://en.wikipedia.org/wiki/True_polar_wander" target="_blank" rel="noopener noreferrer">true polar wander</a>," in which the Earth's rotation and how its magnetic field is situated shifts. Given how vital evidence of Earth's magnetic field and its changes are in geology, there is an entire field of study called <a href="https://en.wikipedia.org/wiki/Paleomagnetism" target="_blank" rel="noopener noreferrer">Paleomagnetism</a>; the next improvement on existing theory will have to account for it. Despite this issue, the focus on plate boundaries is a huge step forward.<br><br><br>Here's the animation showing how the plates have moved over the last billion years:</p>
Some mysteries take generations to unfold.
- In 1959, a group of nine Russian hikers was killed in an overnight incident in the Ural Mountains.
- Conspiracies about their deaths have flourished ever since, including alien invasion, an irate Yeti, and angry tribesmen.
- Researchers have finally confirmed that their deaths were due to a slab avalanche caused by intense winds.
a: Last picture of the Dyatlov group taken before sunset, while making a cut in the slope to install the tent. b: Broken tent covered with snow as it was found during the search 26 days after the event.
Photographs courtesy of the Dyatlov Memorial Foundation.<p>Finally, a <a href="https://www.nature.com/articles/s43247-020-00081-8" target="_blank">new study</a>, published in the Nature journal Communications Earth & Environment, has put the case to rest: it was a slab avalanche.</p><p>This theory isn't exactly new either. Researchers have long been skeptical about the avalanche notion, however, due to the grade of the hill. Slab avalanches don't need a steep slope to get started. Crown or flank fractures can quickly release as little as a few centimeters of earth (or snow) sliding down a hill (or mountain). </p><p>As researchers Johan Gaume (Switzerland's WSL Institute for Snow and Avalanche Research SLF) and Alexander Puzrin (Switzerland's Institute for Geotechnical Engineering) write, it was "a combination of irregular topography, a cut made in the slope to install the tent and the subsequent deposition of snow induced by strong katabatic winds contributed after a suitable time to the slab release, which caused severe non-fatal injuries, in agreement with the autopsy results."</p><p>Conspiracy theories abound when evidence is lacking. Twenty-six days after the incident, a team showed up to investigate. They didn't find any obvious sounds of an avalanche; the slope angle was below 30 degrees, ruling out (to them) the possibility of a landslide. Plus, the head injuries suffered were not typical of avalanche victims. Inject doubt and crazy theories will flourish.</p>
Configuration of the Dyatlov tent installed on a flat surface after making a cut in the slope below a small shoulder. Snow deposition above the tent is due to wind transport of snow (with deposition flux Q).
Photo courtesy of Communications Earth & Environment.<p>Add to this Russian leadership's longstanding battle with (or against) the truth. In 2015 the Investigative Committee of the Russian Federation decided to reopen this case. Four years later the agency concluded it was indeed a snow avalanche—an assertion immediately challenged within the Russian Federation. The oppositional agency eventually agreed as well. The problem was neither really provided conclusive scientific evidence.</p><p>Gaume and Puzrin went to work. They provided four critical factors that confirmed the avalanche: </p><ul><li>The location of the tent under a shoulder in a locally steeper slope to protect them from the wind </li><li>A buried weak snow layer parallel to the locally steeper terrain, which resulted in an upward-thinning snow slab</li><li>The cut in the snow slab made by the group to install the tent </li><li>Strong katabatic winds that led to progressive snow accumulation due to the local topography (shoulder above the tent) causing a delayed failure</li></ul><p>Case closed? It appears so, though don't expect conspiracy theories to abate. Good research takes time—sometimes generations. We're constantly learning about our environment and then applying those lessons to the past. While we can't expect every skeptic to accept the findings, from the looks of this study, a 62-year-old case is now closed.</p><p> --</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank" rel="noopener noreferrer">Facebook</a>. His most recent book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank" rel="noopener noreferrer">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>
A new study analyzed Martian glaciers to discover that the planet had numerous ice ages.
Boulders were found grouped in distinct bands on the surfaces of the Martian glaciers, suggesting multiple ice ages over hundreds of millions of years.
Credit: Levy et al./ PNAS/ Colgate University.
Valles Marineris on Mars is 10 times longer and three times deeper than Earth's Grand Canyon.
- The HiRISE instrument aboard NASA's Mars Reconnaissance Orbiter captured high-resolution images of Valles Marineris.
- Valles Marineris stretches roughly 2,500 miles across the Martian surface, and was likely formed by geologic faulting caused by volcanic activity.
- NASA's Perseverance rover is set to land on Mars in February 2021, where it will search for signs of ancient life.
East-facing slope in Tithonium Chasma
Credit: NASA/JPL/UArizona<p>Over the decades, scientists have proposed many explanations for the origin of Valles Marineris, including erosion by water and the withdrawal of subsurface magma.</p><p>But the most widely accepted theory is that the canyon was formed by<a href="https://marsed.asu.edu/mep/tectonics/canyons" target="_blank"> geologic faulting caused by volcanic activity</a> in the Tharsis region, a volcanic plateau near the Red Planet's equator. (The Tharsis region is home to <a href="https://en.wikipedia.org/wiki/Olympus_Mons" target="_blank" rel="noopener noreferrer">Olympus Mons</a>, one of the largest volcanoes in the solar system.)</p>
Credit: NASA<p>Launched in 2005, HiRISE is the most powerful camera sent to another planet. It's able to capture high-resolution images of objects the size of a kitchen table, in both visible and near-infrared wavelengths. Scientists use these images to study topography and mineral groups on the Martian surface, and to help select potential landing sites for future missions.</p> <p>In February 2021, NASA's Perseverance rover is set to land on Mars, where it will collect rock and soil samples, take high-resolution microscopic images of the surface and search for signs of ancient alien life. The rover will also carry the Ingenuity Mars Helicopter, a small 4-pound drone designed to help scientists learn more about the feasibility of achieving flight on Mars, a planet with an atmosphere that's <a href="https://www.nasa.gov/feature/jpl/6-things-to-know-about-nasas-ingenuity-mars-helicopter/" target="_blank" rel="noopener noreferrer">99 percent less dense than Earth's</a>.</p>