Philippa Kaur

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    in Humans

    Beautiful shell carving was part of Incan offering to Lake Titicaca

    By Jason Arunn Murugesu
    The box was discovered in Lake Titicaca
    Helder Hugo

    This 500-year-old stone box of Inca offerings was found by divers in the Bolivian half of Lake Titicaca. It contains a miniature llama made from mollusc shell and a cylindrical gold foil thought to be a tiny version of an Incan bracelet.
    Christophe Delaere at Free University of Brussels in Belgium and his colleagues think the box and its contents were part of a human sacrifice offering to the lake, as similar pairings of objects have been found in areas associated with Incan sacrifices. “This discovery extends the concept of ‘sacrality’ to the entire lake,” says Delaere.
    The Incas ruled large parts of South America from the early 13th century until the Spanish invaded in the late 1500s. Underwater offerings were mentioned in books by Spanish colonisers, but no intact artefacts have been found until now.
    Journal reference: Antiquity, DOI: 10.15184/aqy.2020.121
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    in Space & Astronomy

    The physics of solar flares could help scientists predict imminent outbursts

    Space weather forecasting is a guessing game. Predictions of outbursts from the sun are typically based on the amount of activity observed on the sun’s roiling surface, without accounting for the specific processes behind the blasts.
    But a new technique could help predict the violent eruptions of radiation known as solar flares based on the physics behind them, researchers report in the July 31 Science. When applied to old data, the method anticipated several powerful flares, although it missed some as well.
    Radiation released in solar flares and associated eruptions of charged particles, or plasma,can be harmful. This space weather can disrupt radio communications, throw off satellites, take down power grids and endanger astronauts (SN: 9/11/17). More accurate forecasts could allow operators to switch off sensitive systems or otherwise make preparations to mitigate negative effects.
    Current prediction methods rely on tracking flare-linked phenomena such as large, complex sunspots — dark regions on the sun’s surface with powerful magnetic fields. But that leads to some false alarms.

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    In contrast, the new prediction method is rooted in the intricacies of how and when the sun’s tangled loops of magnetic fields rearrange themselves, in a process known as magnetic reconnection, releasing bursts of energy that mark solar flares.
    On the sun’s surface, magnetic fields can get gnarly. Magnetic field lines, imaginary contours that indicate the direction of the magnetic field at various locations, loop and cross over one another like well-mixed spaghetti. When those lines break and reconnect, a burst of energy is released, producing a flare. The details of how and under what conditions this happens have yet to be unraveled.
    In the new study, physicist Kanya Kusano from Nagoya University in Japan and colleagues propose that the largest flares result when two arcing magnetic field lines connect, forming an m-shaped loop, as a smaller loop forms close to the sun’s surface. This “double-arc instability” leads to more magnetic reconnection, and the m-shaped loop expands, unleashing energy.
    Using 11 years’ worth of data from NASA’s Solar Dynamics Observatory spacecraft, the researchers identified regions on the sun with high magnetic activity. For each region, the team determined whether conditions were ripe for a flare-inducing double-arc instability, and then aimed to predict the most powerful flares the sun produces, called X-class flares. The technique correctly predicted seven of nine flares that passed a threshold that the researchers chose, called X2, the second strength subdivision of the X-class.
    The successful predictions suggest that researchers may have identified the physical process that underlies some of the largest outbursts.
    “Prediction is a very good benchmark for how well we can understand nature,” Kusano says.
    The unsuccessful predictions are likewise illuminating: “Even if it fails, it tells us something,” says solar physicist Astrid Veronig of the University of Graz in Austria, who wrote a commentary on the result, also published in Science. The two flares that the technique missed had no associated ejection of plasma from the sun’s surface. “This kind of instability is maybe not a good way to explain these other flares,” Veronig says. They may instead have resulted from magnetic reconnection high above, instead of close to, the sun’s surface.
    The mechanism on which the researchers based their prediction “is really interesting and very insightful,” says solar physicist KD Leka of NorthWest Research Associates in Boulder, Colo. But, she notes, the method couldn’t predict how soon the flares will occur — whether the burst would come an hour or a day after the right conditions first occurred — and it didn’t identify slightly weaker X1 flares, or the next class down, known as M-class flares, which could still be damaging.
    “The mantra that I live by,” Leka says, “is any rule you think you’ve figured out about the sun, it’s going to figure out how to break it.” More

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    in Humans

    We’ve finally figured out where Stonehenge’s giant boulders came from

    By Donna Lu
    We finally know where most of Stonehenge’s sarsen stones came from
    Andre Pattenden (English Heritag

    The origins of the giant boulders at Stonehenge have long been a mystery – but now we have uncovered where they came from.
    David Nash at the University of Brighton in the UK and his colleagues have identified the source of 50 of the 52 large boulders, known as sarsens, that make up the monument’s iconic stone circle.
    By analysing the stones’ chemical composition, the team has traced their origins to 25 kilometres away from the monument, in the West Woods in Wiltshire.

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    The sarsens comprise Stonehenge’s outer circle as well as a horseshoe-shaped inner ring. Many are in trilithons: two vertical stones topped with a horizontal lintel.
    Stonehenge also contains smaller rocks, known as bluestones, near its centre, the origins of which have previously been traced to Wales.
    The researchers analysed the chemistry of the sarsens via a technique called portable X-ray fluorescence spectrometry, essentially a handheld X-ray gun. With this, they took five readings at different positions for each stone.

    This revealed that 50 sarsens shared a common chemistry, containing more than 99 per cent silica, with trace elements including aluminium, calcium and iron.
    “Two, much to our surprise, were different to that main cluster, but also different to each other,” says Nash. This suggests they have two separate origins.

    Next, the researchers analysed a fragment of stone, taken from a collapsed sarsen when it was re-erected in 1958, to obtain a geochemical breakdown of the rock. They used this to sample areas of similar stone across southern Britain.
    The site in the West Woods, one of six the team sampled in the Marlborough Downs, turned up with a match. “We didn’t expect we would ever find the original source area,” says Nash.
    Identifying the origins of the sarsens opens up the possibility of future archaeological research into the routes they may have been transported to Stonehenge, says Nash.
    The origins of the other two sarsens have yet to be identified.
    Journal reference: Science Advances, DOI: 10.1126/sciadv.abc0133
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    in Humans

    Sharon Moalem interview: Why women are genetically stronger than men

    We know that women live longer and are less susceptible to certain diseases than men. That may be down to the benefits of having two X chromosomes

    Humans 29 July 2020
    By Sharon Moalem

    Rocio Montoya

    WOMEN generally outlive men and are less susceptible to certain illnesses – including covid-19, it now appears. Why health outcomes are so drastically different between the sexes is unclear. But Sharon Moalem, a doctor and genetic researcher based in New York, thinks he has the answer. It isn’t because women tend to go to the doctor more or have healthier habits, he says. Instead, it’s because they are typically better equipped, genetically speaking.
    In humans, sex is largely determined by chromosomes, the bundles of tightly coiled DNA that carry our genes. The cells of most women possess two X chromosomes while most men have one X and one Y. So that women’s cells don’t have to carry two versions of each gene on the X chromosome, one from each X, one of the Xs is mainly switched off. It appears that which one stays active in which cells is chosen seemingly at random some time during the first few weeks of pregnancy. The result is that half a women’s cells generally use the X chromosome she inherited from her mother, while the other half use the one from her father.
    It has long been known that if one X has a harmful mutation, cells that use the other X can compensate. That’s why, for instance, women are less likely to be colour-blind; a gene important for eye function resides on the X chromosome. Yet Moalem argues that the benefits are far more significant than this alone. He makes the case that even if there is no obviously harmful mutation, women tend to be at an advantage by having bodies … More

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    in Humans

    A weather forecast for fake news outbreaks on social media is coming

    A social media weather report that predicts outbreaks of propaganda is on its way. It can’t arrive soon enough, says Annalee Newitz

    Technology | Comment 29 July 2020
    By Annalee Newitz

    Will Heath/NBCU Photo Bank/NBC

    A FEW weeks ago, I noticed that a foul and offensive hashtag was trending on Twitter. Like a horror movie character who goes into the basement after hearing monster noises, I clicked on it.
    Every post on the hashtag was like a parody of a political debate, with each side making the same screaming accusations. It was almost as if these people had learned to argue from bad algorithms.
    That is when it hit me. Maybe these angry tweets were generated by algorithms. Or by operatives at a place like the Internet Research Agency … More

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    in Humans

    Proxima review: Eva Green shines as a troubled astronaut

    Alice Winocour’s new film Proxima shows the difficulties of balancing family life with a career as an astronaut, finds Simon Ings

    Humans 29 July 2020
    By Simon Ings
    Astronaut Sarah Loreau (Eva Green) prepares to leave Earth in Proxima
    Dharamsala & Darius films

    Proxima
    Alice Winocour

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    In UK cinemas from 31 July
    THE year before Apollo 11’s successful mission to the moon, Robert Altman directed James Caan and Robert Duvall in Countdown. The 1968 film stuck to the technology of its day, pumping up the drama with a somewhat outlandish mission plan: astronaut Lee Stegler and his shelter pod are sent to the moon’s surface on separate flights and Stegler must find the shelter once he lands if he is to survive.
    The film played host to characters you might conceivably bump into at the supermarket: the astronauts, engineers and bureaucrats have families and everyday troubles not so very different from your own.
    Proxima is Countdown for the 21st century. Sarah Loreau, an astronaut played brilliantly by Eva Green, is given a last-minute opportunity to join a Mars precursor mission to the International Space Station. Loreau’s training and preparation are impressively captured on location at European Space Agency facilities in Cologne, Germany – with a cameo from French astronaut Thomas Pesquet – and in Star City, the complex outside Moscow that is home to the Yuri Gagarin Cosmonaut Training Center. She is ultimately headed to launch from Baikonur in Kazakhstan.
    Comparing Proxima with Countdown shows how much both cinema and the space community have changed in the past half-century. There are archaeological traces of action-hero melodramatics in Proxima, but they are the least satisfying parts of the movie. Eva Green is a credible astronaut and a good mother, pushed to extremes on both fronts and painfully aware that she chose this course for herself. She can’t be all things to all people all of the time and, as she learns, there is no such thing as perfect.

    Because Proxima is arriving late – its launch was delayed by the covid-19 lockdown – advances in space technology have already somewhat gazzumped Georges Lechaptois’s metliculous location cinematography. I came to the film still reeling from watching the Crew Dragon capsule Endeavour lift off from Kennedy Space Center on 20 May.
    That crewed launch was the first of its kind from US soil since NASA’s space shuttle was retired in 2011 and looked, from the comfort of my sofa, about as eventful as a ride in an airport shuttle bus. So it was hard to take seriously those moments in Proxima when taking off from our planet’s surface is made the occasion for an existential crisis. “You’re leaving Earth!” exclaims family psychologist Wendy (Sandra Hüller) at one point, thoroughly earning the look of contempt that Loreau shoots at her.
    Proxima‘s end credits include endearing shots of real-life female astronauts with their very young children – which does raise a bit of a problem. The plot largely focuses on the impact of bringing your child to work when you spend half your day in a spacesuit at the bottom of a swimming pool. “Cut the cord!” cries the absurdly chauvinistic NASA astronaut Mike Shannon (Matt Dillon) when Loreau has to go chasing after her young daughter.
    Yet here is photographic evidence that suggests Loreau’s real-life counterparts – Yelena Kondakova, Ellen Ochoa, Cady Coleman and Naoko Yamazaki – managed perfectly well on multiple missions without all of Proxima‘s turmoil. Wouldn’t we have been better off seeing the realities they faced rather than watching Loreau, in the film’s final moments, break Baikonur’s safety protocols in order to steal a feel-good, audience-pandering mother-daughter moment?
    For half a century, movies have struggled to keep up with the rapidly changing realities of the space sector. Proxima, though interesting and boasting a tremendous central performance from Green, proves to be no more relevant than its forebears.
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    in Space & Astronomy

    An Antarctic ice dome may offer the world’s clearest views of the night sky

    An observatory in the heart of Antarctica could have the world’s clearest views of the night sky.
    If an optical telescope were built on a tower a few stories tall in the middle of the Antarctic Plateau, it could discern celestial features about half the size of those typically visible to other observatories, researchers report online July 29 in Nature. The observatory would achieve such sharp vision by peering above the atmosphere’s lowermost layer, known as the boundary layer, responsible for much of the undulating air that muddles telescope images (SN: 10/4/18).
    The thickness of Earth’s boundary layer varies across the globe. Near the equator, it can be hundreds of meters thick, limiting the vision of premier optical telescopes in places like the Canary Islands and Hawaii (SN: 10/14/19). Those telescopes usually cannot pick out celestial features smaller than 0.6 to 0.8 arc seconds — the apparent width of a human hair from about 20 meters away.
    “But in Antarctica, the boundary layer is really thin,” says Bin Ma, an astronomer at the Chinese Academy of Sciences in Beijing, “so it is possible to put a telescope above.”
    Ma and colleagues took the first-ever measurements of nighttime atmospheric blur from the highest point in East Antarctica, called Dome A. From April to August 2019, instruments on an 8-meter-tall tower at China’s Kunlun research station tracked how Earth’s atmospheric turbulence distorted incoming starlight. A nearby weather station also monitored atmospheric conditions, such as temperature and wind speed. Using these observations, researchers characterized the boundary layer at Dome A and its effect on telescope observations.
    From April to August 2019, instruments atop an 8-meter-tall tower at China’s Kunlun research station in East Antarctica observed how the local atmosphere distorted light from celestial objects.Zhaohui Shang
    The boundary layer was, on average, about 14 meters thick; as a result, the light sensors at the top of the 8-meter tower were completely free of boundary layer blur only about one-third of the time. But when these instruments were above the layer, atmospheric interference was so low that a telescope could pick out details on the sky 0.31 arc seconds across, on average. The best recorded atmospheric conditions would let a telescope see features as small as 0.13 arc seconds.
    “One-tenth of an arc second is extremely good,” says Marc Sarazin, an applied physicist at the European Southern Observatory in Munich who was not involved in the work. This is “really something you rarely achieve in Chile or on Mauna Kea” in Hawaii.
    Researchers have found similarly excellent visibility above the boundary layer at another spot on the Antarctic Plateau, known as Dome C. But the boundary layer there is around 30 meters thick — making it more difficult to build an observatory above it. An optical telescope planned for construction on a 15-meter tower at Kunlun could take advantage of Dome A’s stellar views above the boundary layer, Ma says. Such crisp telescope images could help astronomers study a range of celestial objects, from solar system bodies to distant galaxies.

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    in Humans

    The illnesses caused by a disconnect between brain and mind

    A group of troubling disorders including functional neurological disorders can lead to very real symptoms, but tests suggest nothing is wrong. Finding out why is shedding new light on the nature of consciousness itself. Jamie Lacelle suffers from a functional neurological disorder. This is her story. More