Philippa Kaur

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    in Space & Astronomy

    A bounty of potential gravitational wave events hints at exciting possibilities

    A new crew of potential ripples in spacetime has just debuted — emphasis on the word “potential.”

    By loosening the criteria for what qualifies as evidence for gravitational waves, physicists identified 1,201 possible tremors. Most are probably fakes, spurious jitters in the data that can mimic the cosmic vibrations, the team reports August 2 at arXiv.org. But by allowing in more false alarms, the new tally may also include some weak but genuine signals that would otherwise be missed, potentially revealing exciting new information about the sources of gravitational waves.

    Scientists can now look for signs that may corroborate some of the uncertain detections, such as flashes of light in the sky that flared from the cosmic smashups that set off the ripples. Gravitational waves are typically spawned by collisions of dense, massive objects, such as black holes or neutron stars, the remnants of dead stars (SN: 1/21/21).

    To come up with the new census, physicists reanalyzed six months of data from the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, and Virgo gravitational wave observatories. Scientists had already identified 39 of the events as likely gravitational waves in earlier analyses.

    Eight events that hadn’t been previously identified stand a solid chance of being legitimate — with greater than a 50 percent probability of coming from an actual collision.

    The physicists analyzed the data from those eight events to see how they might have occurred. In one, two black holes may have slammed together, melding into a whopper black hole with about 180 times the mass of the sun, which would make it the biggest black hole merger seen yet (SN: 9/2/20). Another event could be a rare sighting of a black hole swallowing a neutron star (SN: 6/29/21). More

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    in Humans

    Babylonians calculated with triangles centuries before Pythagoras

    By Michael Marshall

    The Plimpton 322 tabletAndrew Kelly/Rare Books and Manuscripts Library, Columbia University
    The ancient Babylonians understood key concepts in geometry, including how to make precise right-angled triangles. They used this mathematical know-how to divide up farmland – more than 1000 years before the Greek philosopher Pythagoras, with whom these ideas are associated.
    “They’re using a theoretical understanding of objects to do practical things,” says Daniel Mansfield at the University of New South Wales in Sydney, Australia. “It’s very strange to see these objects almost 4000 years ago.”
    Babylonia was one of several overlapping ancient societies in Mesopotamia, a region of southwest Asia that was situated between the Tigris and Euphrates rivers. Babylonia existed in the period between 2500 and 500 BC, and the First Babylonian Empire controlled a large area between about 1900 and 1600 BC.Advertisement
    Mansfield has been studying a broken clay tablet from this period, known as Plimpton 322. It is covered with cuneiform markings that make up a mathematical table listing “Pythagorean triples”. Each triple is the lengths of the three sides of a right-angled triangle, where each side is a whole number. The simplest example is (3, 4, 5); others include (5, 12, 13) and (8, 15, 17).
    The triangles’ sides are these lengths because they obey Pythagoras’s theorem: the square of the longest side is equal to the sum of the squares of the other two sides. This classic bit of mathematics is named for the Greek philosopher Pythagoras, who lived between about 570 and 495 BC – long after the Plimpton 322 tablet was made.
    “They [the early Babylonians] knew Pythagoras’ theorem,” says Mansfield. “The question is why?”

    Mansfield thinks he has found the answer. The key clue was a second clay tablet, dubbed Si.427, excavated in Iraq in 1894. Mansfield tracked it down to the Istanbul Archaeology Museums.
    Si.427 was a surveyor’s tablet, used to make the calculations necessary to fairly share out a plot of land by dividing it into rectangles. “The rectangles are always a bit wonky because they’re just approximate,” says Mansfield. But Si.427 is different. “The rectangles are perfect,” he says. The surveyor achieved this by using Pythagorean triples.
    “Even the shapes of these tablets tell a story,” says Mansfield. “Si.427 is a hand tablet… Someone’s picked up a piece of clay, stuck it in their hand and wrote on it while surveying a field.” In contrast, Plimpton 322 seems to be more of an academic text: a systematic investigation of Pythagorean triples, perhaps inspired by the difficulties surveyors had. “Someone’s got a huge slab of clay… [and] squashed it flat” while sitting at a desk, he says.
    Journal reference: Foundations of Science, DOI: 10.1007/s10699-021-09806-0
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    in Space & Astronomy

    Black holes born with magnetic fields quickly shed them

    Like a shaggy dog in springtime, some black holes have to shed. New computer simulations reveal how black holes might discard their magnetic fields.

    Unlike dogs with their varied fur coats, isolated black holes are mostly identical. They are characterized by only their mass, spin and electric charge. According to a rule known as the no-hair theorem, any other distinguishing characteristics, or “hair,” are quickly cast off. That includes magnetic fields.

    The rule applies to black holes in a vacuum, where magnetic fields can simply slip away. But, says astrophysicist Ashley Bransgrove of Columbia University, “what we were thinking about is what happens in a more realistic scenario.” A magnetized black hole would typically be surrounded by electrically charged matter called plasma, and scientists didn’t know how — or even if — such black holes would undergo hair loss.

    Black holes can be born with magnetic fields or gain them later, for example by swallowing a neutron star, a highly magnetic dead star (SN: 6/29/21). When Bransgrove and colleagues simulated the plasma surrounding a magnetized black hole, they found that a process called magnetic reconnection allows the magnetic field to escape the black hole. The magnetic field lines that map out the field’s direction break apart and reconnect. Loops of magnetic field form around blobs of plasma, some of which blast outward, while others fall into the black hole. That process eliminates the black hole’s magnetic field, the researchers report in the July 30 Physical Review Letters.

    Magnetic reconnection in balding black holes could spew X-rays that astronomers could detect. So scientists may one day glimpse a black hole losing its hair. More

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    in Humans

    Old review: M. Night Shyamalan's stylish horror of accelerated ageing

    By Francesca Steele

    Guy (Gael García Bernal) and Prisca (Vicky Krieps) in OldUniversal Pictures
    Time is definitely not a healer in Old, the latest film from writer, director and producer M. Night Shyamalan, where the bodies of stranded tourists hurtle towards old age at an accelerated rate due to a local geological quirk.
    This fascinating (and, typically for Shyamalan, high-concept) premise raises all sorts of thorny questions. What is important to us when time is short? What can time teach us –  and what can it steal from us? Can ageing prosthetics ever be applied convincingly?
    Shyamalan, the film-maker behind supernatural thrillers including The Sixth Sense and The Village, has become as famous for the disappointing execution of excellent premises as he is for dreaming them up in the first place.Advertisement
    Old, based loosely on the graphic novel Sandcastle by Pierre Oscar Lévy and Frederik Peeters, starts out as one of Shyamalan’s best efforts in years. It begins with such creepy camera angles and creepy casting that the slow pacing for which he is sometimes lambasted works perfectly.
    Dread rises from the outset. Guy (Gael García Bernal) and Prisca (Vicky Krieps) have brought their children, 6-year-old Trent (Nolan River) and 11-year-old Maddox (Alexa Swinton), to an idyllic resort that Prisca pointedly reminds us she found randomly on the internet.

    The dialogue is a little excessive. “You’re always thinking about the future. It makes me feel not seen!” yells Prisca. “You’re always thinking about the past. You work in a goddamn museum,” retorts Guy.
    But if the script feels clunky, the production doesn’t. The family swan around their lush hotel room, as the camera spies them menacingly from outside like a predator. Trent has a habit of asking random hotel guests what they do for a living, but the way the camera pans across his subjects’ faces makes the exchange feel unsettling rather than adorable, as if we’re being introduced to an ensemble soon to be picked off.
    A special day at an idyllic, private beach is arranged by the over-eager hotel manager. At the cove, hemmed in by rocks and swiftly abandoned by their shifty driver (Shyamalan himself, in the kind of cameo role beloved of Alfred Hitchcock), they find themselves stranded with a cast of characters worthy of an Agatha Christie murder mystery.
    There is a doctor (Rufus Sewell, on fabulously sinister form), his trophy wife (Abbey Lee), their young daughter (Mikaya Fisher) and his mother (Kathleen Chalfant). Then there is psychologist Patricia (Nikki Amuka-Bird), who has epilepsy, her nurse-husband (Ken Leung) and a rapper (Aaron Pierre) whose partner washes up dead (and naked) the moment they arrive, heralding an onset of strange and increasingly grotesque symptoms.

    Swimsuits become too tight. Patricia’s seizures disappear. A tumour balloons in minutes and must be cut out right there on the beach. A pregnancy is delivered moments after it begins.
    There is no doubting Shyamalan’s talent for suspense. In the film’s first half, he labours lovingly over one shot where characters age years as the camera pans across the beach. In other scenes, it perches just behind children’s heads so we can observe their parents’ alarmed expressions without knowing precisely what is so shocking. Like a Stephen King novel, the horror here is not in the revelation but the build-up.
    Sadly, Old is a stylistic triumph but a narrative dud. The second half of the film is severely hampered by too many undercooked ideas and a plot too intent on explaining itself. All those questions about what value we put on time – or ought to – are skirted over too fast. Philosophical enquiry makes way for a signature Shyamalan plot twist, which, in the end, feels perfunctory and unsurprising.
    The film quickly loses its grip when it asks us to emotionally invest in characters even as it dispatches them one by one, collapsing in the process from a sinister body horror into a confused (sand)castle in the air.
    Old is in UK and US cinemas now

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    in Space & Astronomy

    A super-short gamma-ray burst defies astronomers’ expectations

    A surprisingly short gamma-ray burst has astronomers rethinking what triggers these celestial cataclysms.

    The Fermi Gamma-ray Space Telescope detected a single-second-long blast of gamma rays, dubbed GRB 200826A, in August 2020. Such fleeting gamma-ray bursts, or GRBs, are usually thought to originate from neutron star smashups (SN: 10/16/17). But a closer look at the burst revealed that it came from the implosion of a massive star’s core.

    In this scenario, the core of a star collapses into a compact object, such as a black hole, that powers high-speed particle jets. Those jets punch through the rest of the star and radiate powerful gamma rays before the outer layers of the star explode in a supernova (SN: 5/8/19). That process is typically thought to produce longer GRBs, lasting more than two seconds.

    Discovering such a brief gamma-ray burst from a stellar explosion suggests that some bursts previously classified as stellar mergers may actually be from the deaths of massive stars, researchers report online July 26 in two studies in Nature Astronomy.

    The first clues about GRB 200826A’s origin came from the burst itself. The wavelengths of light and amount of energy released in the burst were more similar to collapse-related GRBs than collision-produced bursts, Bing Zhang, an astrophysicist at the University of Nevada, Las Vegas, and colleagues report. Plus, the burst hailed from the middle of a star-forming galaxy, where astronomers expect to find collapsing massive stars, but not neutron star mergers — which are generally found on the fringes of tranquil galaxies.

    Another group, led by astronomer Tomás Ahumada-Mena of the University of Maryland in College Park, searched for the supernova that’s expected to follow a GRB produced by a collapsing star. Using the Gemini North Telescope in Hawaii to observe GRB 200826A’s host galaxy, the team was able to pick out the telltale infrared light of the supernova. The burst may have been so brief because its jets had just barely punched through the surface of the star before they petered out and the star blew up, Ahumada-Mena says. More

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    in Humans

    Ancient humans in Europe may have stolen food from wild hunting dogs

    By Krista Charles

    Artist’s impression of a pack of Eurasian hunting dogs chasing preyMauricio Antón with scientific supervision by D. Lordkipanidze and B. Martínez-Navarro
    The earliest humans known to have lived outside Africa shared their environment with hunting dogs – and may even have stolen food from them.
    For many years, archaeologists have been excavating at a site near Dmanisi in Georgia, where they have found evidence that ancient humans – sometimes put in the species Homo erectus – were present about 1.8 million years ago. The Dmanisi humans provide the earliest fossil evidence yet found of hominins outside Africa.
    But as ancient humans moved out of Africa, it looks like they encountered prehistoric hunting dogs that were moving into Africa, because the remains of one such dog has now been unearthed at Dmanisi.Advertisement
    Saverio Bartolini-Lucenti at the University of Florence, Italy, and his colleagues analysed the remains, which came from a young adult Eurasian hunting dog (Canis (Xenocyon) lycaonoides), an extinct species of hunting dog related to modern African hunting dogs (Lycaon pictus).
    “Picture an African hunting dog, but stouter with long limbs like an Irish wolfhound, but not so thin,” says Bartolini-Lucenti.

    This particular animal would have lived about 1.8 million years ago, making it the earliest ever found in Europe.
    These wild dogs are believed to have originated in Asia, spreading into and across Europe and Africa between about 1.8 and 0.8 million years ago.
    “Finding it in Dmanisi – which is an important site at the verge, the border of three continents (Asia, Africa and Europe) – is interesting because it is at a timeframe where we didn’t have any occurrences of this form,” says Bartolini-Lucenti.
    Modern African hunting dogs have adapted to consume their prey very quickly before it can be stolen by larger, stronger predators, such as lions and hyenas. The Eurasian hunting dogs may have interacted with early humans in a similar way, says Bartolini-Lucenti, with the humans scaring off the dogs to steal their prey.
    Working out how two ancient species interacted is difficult, “especially when the fossil record is poor”, says Marco Cherin at the University of Perugia in Italy. “But I am confident that the record from Dmanisi may offer new surprises in the future, and this paper represents a good beginning.”
    Journal reference: Scientific Reports, DOI: 10.1038/s41598-021-92818-4
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    in Humans

    People happily steal from groups even if they are generous one-on-one

    By Clare Wilson

    Would you share or steal?PURPLE MARBLES/Alamy
    Most people play fair in lab tests where they can share or steal small sums of money – yet in real life, unfairness and cheating is common.
    Now, the apparent contradiction has a new explanation. In lab experiments where people are able to take money from groups of people, they nearly always do, but the same individuals tend to be fair when dealing with just one other person.
    Economists have long investigated people’s behaviour through simple tests in the lab, such as the two-person “dictator game” in which one person is given a small sum of money and they choose whether to give some of it to their playing partner, who they haven’t met before. Typically, most people give some away, although they get nothing in return, suggesting we have an intrinsic sense of fairness.Advertisement
    In real life, though, unfairness is common, ranging from office workers failing to contribute their share of communal snacks through to large-scale financial fraud. We often assume that people who cheat in such ways are a minority, or even that antisocial people are drawn to careers where they can exploit others, says Carlos Alós-Ferrer at the University of Zurich in Switzerland.
    To investigate, Alós-Ferrer’s team designed a new monetary test called the Big Robber game, where any unfair actions affect larger numbers of people.

    The researchers asked groups of 32 people to play the dictator game and two other similar games in pairs, and the results were the same as those usually seen, in that most people acted generously.
    Half the group were also asked if they would like to rob some of the earnings of the other half, which totalled €200, on average. They could take half the amount, a third, a tenth or none of it. The team repeated this process with 640 people in total.
    Of the 320 individuals given the robbery option, 98 per cent took at least some of the money and 56 per cent took half. To save on costs, the researchers didn’t let everyone actually go home with their chosen amount, but one of the 16 robbers in each group was randomly selected to receive this sum.
    The findings suggest that people can be fair to individuals and selfish to larger groups, says Alós-Ferrer. “Human beings are perfectly capable of displaying both kinds of behaviour.”
    People may act differently in real life to how they do in lab games, but the findings suggest economists should investigate group interactions as well as two-person ones, he says.
    Journal reference: Nature Human Behaviour, DOI: 10.1038/s41562-021-01170-0

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    Striking image of covid-19 clean-up is among photo contest finalists

    By Gege Li

    Aly Song/Wellcome Photography Prize 2021
    Wellcome Photography Prize 2021
    THESE poignant and intensely personal images are among the winners and finalists in the Wellcome Photography Prize 2021, run by health research foundation Wellcome.
    The competition focuses on three of the most urgent global health challenges: mental health, global warming and infectious disease. There are two top prizes, one for a single image and one for an image series.Advertisement
    Above is The Time of Coronavirus by finalist Aly Song. Taken in April 2020, volunteers are disinfecting Qintai Grand Theatre in Wuhan, China, the city where covid-19 cases were first detected.
    Next,  is a shot from Yoppy Pieter, winner of the image series prize, called Trans Woman: Between colour and voice. It shows one aspect of life for transgender women in Indonesia, with Lilis (centre), a trans woman, being tested for HIV in South Tangerang. It can be difficult for trans women in the country to access healthcare without official documents.
    Yoppy Peiter/Wellcome Photography Prize 2021
    Below is Climate Cost by finalist Zakir Hossain Chowdhury. The devastating image was taken three months after Cyclone Amphan struck Bangladesh in May 2020. The cyclone is estimated to have left half a million people homeless.
    Zakir Hossain Chowdhury/Wellcome Photography Prize 2021
    The final image, at bottom right, is Untangling by Jameisha Prescod, winner of the single image prize. It illustrates her isolation through a photo taken in her bedroom during lockdown. She turned to knitting to ease her mind, she says.
    Jameisha Prescod/Wellcome Photography Prize 2021

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