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    Scientists are often cautious or wrong – and that’s OK

    We like to think that science can give us definitive answers to our questions, but uncertainty is a crucial part of the scientific process, says Chanda Prescod-Weinstein

    Humans

    | Comment

    15 September 2021

    By Chanda Prescod-Weinstein

    Lidiia/Shutterstock
    EARLIER this month, science journalist Adam Mann reported a story for Science News that had one of my favourite headlines of 2021: “Astronomers may have seen a star gulp down a black hole and explode.”
    The article discusses a new paper, published in Science on 3 September, that describes observations of a supernova that were collected with the Very Large Array radio telescope in New Mexico. The strong radio signal observed in coordination with this event suggested to lead researcher Dillon Dong and his team that they should follow up using a different set of tools, this time through … More

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    Index, a history of the: Exploring the rivalries in how we search

    By Simon Ings

    An argument abouthow to read has been raging for millenniaSTR/AFP via Getty Images
    Index
    A History of the Dennis Duncan
    Allen LaneAdvertisement

    EVERY once in a while a book comes along to remind us that the idea of the internet isn’t new. Authors like Siegfried Zielinski and Jussi Parikka have written handsomely about their adventures in “media archaeology”, revealing the arcane delights of the 18th-century electrical tele-writing machine of Joseph Mazzolari or Melvil Dewey’s decimal system of book classification of 1873.
    It is a charming business, to discover the past in this way, but it does have its risks. It is all too easy to fall into complacency, congratulating the thinkers of past ages for having caught a whiff, a trace, a spark of what was to come.
    So it is always welcome when an academic writer – in this case Dennis Duncan, a lecturer in English at University College London – takes the time and trouble to tell this story straight, beginning at the beginning and ending at the end.
    Index, A History of the is his story of textual search, told through portrayals of some of the most sophisticated minds of their era, from monks and scholars shivering among the cloisters of 13th-century Europe to server-farm administrators sweltering behind the glass walls of Silicon Valley.
    It is about the unspoken and always collegiate rivalry between two kinds of search: the subject index – which is a humanistic exercise, largely un-automatable, that requires close reading, independent knowledge, imagination and even wit – and the concordance, an eminently automatable listing of words in a text and their locations.
    Hugh of Saint-Cher is the father of the concordance: his list of every word in the Bible and its location, begun in 1230, was a miracle of miniaturisation, smaller than a modern paperback. It and its successors were useful, too, for clerics who knew their Bible almost by heart.
    But the subject index is a superior guide when the content is unfamiliar to the reader. It is Robert Grosseteste, born in Suffolk in around 1175, who we should thank for turning the medieval distinctio – an associative list of concepts, handy for sermon-builders – into something like a modern back-of-book index.
    Reaching the present day, we find that with the arrival of digital search, the concordance is once again ascendant (the search function, Ctrl-F, whatever you want to call it, is an automated concordance), while the subject index and its poorly recompensed makers are struggling to keep up in an age of reflowable screen text.
    Running under this story is a deeper debate, between those who want to access their information quickly, and those (especially authors) who want people to read books from beginning to end.
    This argument about how to read has been raging for millennia, and with good reason. There is clear sense in Socrates’s argument against reading itself, as recorded in Plato’s Phaedrus in 370 BCE: “You have invented an elixir not of memory, but of reminding,” his mythical King Thamus complains.
    Plato knew a thing or two about the psychology of reading, too: people who just look up what they need “are for the most part ignorant”, says Thamus, “and hard to get along with, since they are not wise, but only appear wise”.
    Anyone who spends too many hours a day on social media will recognise that portrait – if they haven’t already come to resemble it.
    Duncan’s arbitration of this argument is a wry one. Scholarship, rather than being timeless and immutable, “is shifting and contingent”, he says, and the questions we ask of our texts “have a lot to do with the tools at our disposal”.

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    Karmalink review: An intriguing mix of Buddhism and nanotech

    By Davide Abbatescianni

    Karmalink is set in a near-future version of Phnom Penh, CambodiaRobert Leitzell
    Film
    Karmalink
    Jake WachtelAdvertisement
    THAT Jake Wachtel’s Karmalink is the opening title of Venice International Film Critics’ Week is a good sign of promise. It is an enigmatic sci-fi drama that will leave you with many things to ponder.
    The story follows a 13-year-old boy, Leng Heng (the late Leng Heng Prak), who claims to see glimpses of his past lives through his dreams. He and his family live in a poor district of a near-future version of Phnom Penh, the capital of Cambodia, and his community is set to relocate 15 kilometres away to make space for a new railway connection to Beijing.
    Leng Heng convinces his friends that finding a golden Buddha that he has seen in his dreams may save their homes, and they seek out help from a street-smart girl, Srey Leak (Srey Leak Chitth).
    Through accurate production design and well-crafted special effects, the world depicted by Karmalink is populated by drones, gigantic QR codes, simultaneous translation devices and the widespread use of virtual reality. It is a place where the rich can avail of advanced nanotechnology and the poor still live in slums, surrounded by dirt and waste.
    To record Leng Heng’s dreams and discover the secrets of his past lives, Srey Leak steals Leng Heng’s sister’s AUGR (short for “augmented reality”), a sort of forehead microchip that works through the injection of special “nanobugs”. During his oneiric explorations, Leng Heng meets Vattanak Sovann (Sahajak Boonthanakit), a neuroscientist and the inventor of the Connectome, a mysterious device containing “a digital replica of one’s consciousness” that can open “a path to enlightenment” through neural connections with the user’s past lives.
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    Despite the many interesting parts of this engaging premise, cracks start to appear towards the end of the first half. The search for the golden Buddha, which is mostly carried out by the two young lead characters, sees them having little trouble in accessing information and breaking into abandoned or inhabited places.
    They travel in and around the city and meet many adults on their way, none of whom ever questions their actions or asks why the children are buying nanotech. They even manage to sneak into Vattanak and his assistant Sofia (Cindy Sirinya Bishop)’s lab, which it isn’t properly guarded and so is easily accessed by two teens. The whole search is generally too smooth, with few obstacles to overcome. One hint comes after the other until the ending.
    “The world of Karmalink is populated by drones, gigantic QR codes and simultaneous translation devices”
    The cinematography in the film really is stunning, and the grim score backs this up. The two young leads – who speak Khmer throughout – are particularly impressive actors. By comparison, the English-language cast – Boonthanakit and Bishop – deliver rather flat performances, sounding a bit too cold-hearted in some of the most tense scenes.
    Altogether, Karmalink had the potential to be a gem. Yet the narrative’s weaknesses overshadow much of the second half, leaving it as more of a rock in need of a good polish. The idea of intertwining Buddhist reincarnation and nanotech is certainly original and the striking contrast between a hyper-technological world and some of the poorest people in society is interesting to watch, but these strengths aren’t enough to make Karmalink as compelling as it should be.

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    The microbial gunk that hardens on teeth is revealing our deep past

    Plaque fossilises while we are still alive. Now, dental calculus is giving up the secrets of our ancient ancestors, from what they ate to how they interacted and evolved

    Humans

    15 September 2021

    By Graham Lawton

    Spencer Wilson
    IT IS the only part of your body that fossilises while you’re still alive,” says Tina Warinner at the Max Planck Institute for the Science of Human History in Jena, Germany.
    To see what she is describing, stand in front of a mirror and examine the rear surfaces of your lower front teeth. Depending on your dental hygiene, you will probably see a thin, yellowish-brown line where the enamel meets the gum. This is plaque, a living layer of microbes that grows on the surface of teeth – or, more accurately, on the surface of older layers of plaque. If … More

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    Generation Covid: What the pandemic means for young people’s futures

    By Bobby Duffy

    Roberto Cigna
    TOO often discussion of generations descends into stereotypes and manufactured conflicts – avocado-obsessed, narcissistic millennials against selfish, wasteful baby boomers. Instead of serious analysis, we get apocryphal predictions about millennials “killing” everything from wine corks to the napkin industry.
    Such discourse wouldn’t be so worrisome if it didn’t sully genuine research into generational differences, a powerful tool to understand and anticipate societal shifts. They can provide unique and often surprising insights into how societies and individuals develop and change.
    That is because generational changes are like tides: powerful, slow-moving and relatively predictable. Once a generation is set on a course, it tends to continue, which helps us see likely futures. That is true even through severe shocks like war or pandemic, which tend to accentuate and accelerate trends. Existing vulnerabilities are ruthlessly exposed, and we are pushed further and faster down paths we were already on.
    We tend to settle into our value systems and behaviours during late childhood and early adulthood, so generation-shaping events have a stronger impact on people who experience them while coming of age. This is why it is vitally important to heed the lessons we learn by looking at previous generations so we can understand what the covid-19 pandemic will mean for those growing up through it, and use those insights to help Generation Covid meet the unprecedented challenges ahead.
    Some approaches that define swathes of the population purely on when people were born are closer to astrology than serious analysis. The type of generational analysis I use in my new book, Generations: Does when you’re born shape who you are?, however, is built … More

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    Younger generations are the most fatalistic about climate change

    By Bobby Duffy

    FILIPPO MONTEFORTE/AFP via Getty Images
    The idea that younger generations care the most about the climate while older people downplay the issue and refuse to take action is a widespread myth, according to new research.
    To better understand differences between generations, including how they perceive one another and the biggest challenges of the day, my team at the Policy Institute at King’s College London and New Scientist commissioned a survey of more than 4000 people aged 18 and over in the US and UK. Responses were collected from 2 to 9 August.
    Previous research has made clear that one of the most pervasive and destructive generational myths is that older cohorts don’t care about the environment or social purpose more generally. The new survey shows how dangerously caricatured this is.Advertisement

    In the UK, over three-quarters of baby boomers – who are defined as those currently aged 56-76 –  agree that climate change, biodiversity loss and other environmental issues are big enough problems that they justify significant changes to people’s lifestyles. This was as high as any other generation (see chart). Seven in 10 of this group say they are willing to make changes to their own lifestyle, completely in line with younger generations.
    Older generations are also less fatalistic than the young: only one in five baby boomers say there is no point in changing their behaviour to tackle climate change because it won’t make any difference, compared with a third of Generation Z – those aged 18-25. This is an important driver of how we act: a sense that all is already lost leads to inertia.
    But our study shows that people have a rather different impression of who thinks what: when we ask people which age group is most likely to say there is no point in changing their behaviour, the oldest group is the most likely to be picked out. We wrongly think they have given up. Social psychologists call this misconception “pluralistic ignorance”. It is an important effect, because it shapes our views of others.

    Older people’s concern isn’t just expressed with words, but reflected in their actions. We know from other studies that it is actually baby boomers and Generation X who are the most likely to have boycotted products. But our new study shows that also isn’t the perception. The majority of the public wrongly think it is Generation Z or millennials who are most likely to boycott products, and only 8 per cent pick out baby boomers and just 9 per cent choose Gen X.
    No contest
    It is no surprise that the public have the wrong impression. Endless articles and analyses paint the picture of a clean generational break in environmental concern and action, with a new cohort of young people coming through who will drive change, if only older people would stop blocking them. Time magazine, for example, called Greta Thunberg “an avatar in a generational battle” when it made her its Person of the Year in 2019.

    This isn’t just wrong, but dangerous, as it dismisses the real concern among large proportions of our economically powerful and growing older population.
    The aftermath of the pandemic means it is set to become harder, not easier, to think about the long term, as short-term needs become more pressing: we will need all the support we can get, and creating or exaggerating generational division won’t help.
    Sign up for Countdown to COP26, our free newsletter covering this crucial year for climate policy

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    Piles of animal dung reveal the location of an ancient Arabian oasis

    By Jake Buehler

    The piles of faeces made by rock hyraxes hold clues to our own pastNatalia Kuzmina / Alamy
    Fossilised piles of faeces, called middens, have revealed that a desert valley in Yemen was once a tropical oasis, which may have lasted in the dry region because of human land management practices.
    Today, Wadi Sana is a dry, rocky desert. We knew that between 11,000 and 5000 years ago, the Arabian peninsula and Sahara desert were wetter than they are now, and some lake-bed deposits suggested that grasslands and trees may have grown elsewhere in the interior … More

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    A supernova’s delayed reappearance could pin down how fast the universe expands

    A meandering trek taken by light from a remote supernova in the constellation Cetus may help researchers pin down how fast the universe expands — in another couple of decades.

    About 10 billion years ago, a star exploded in a far-off galaxy named MRG-M0138. Some of the light from that explosion later encountered a gravitational lens, a cluster of galaxies whose gravity sent the light on multiple diverging paths. In 2016, the supernova appeared in Earth’s sky as three distinct points of light, each marking three different paths the light took to get here.

    Now, researchers predict that the supernova will appear again in the late 2030s. The time delay — the longest ever seen from a gravitationally lensed supernova — could provide a more precise estimate for the distance to the supernova’s host galaxy, the team reports September 13 in Nature Astronomy. And that, in turn, may let astronomers refine estimates of the Hubble constant, the parameter that describes how fast the universe expands.

    The original three points of light appeared in images from the Hubble Space Telescope. “It was purely an accident,” says astronomer Steve Rodney of the University of South Carolina in Columbia. Three years later, when Hubble reobserved the galaxy, astronomer Gabriel Brammer at the University of Copenhagen discovered that all three points of light had vanished, indicating a supernova.

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    By calculating how the intervening cluster’s gravity alters the path the supernova’s light rays take, Rodney and his colleagues predict that the supernova will appear again in 2037, give or take a couple of years. Around that time, Hubble may burn up in the atmosphere, so Rodney’s team dubs the supernova “SN Requiem.”

    “It’s a requiem for a dying star and a sort of elegy to the Hubble Space Telescope itself,” Rodney says. A fifth point of light, too faint to be seen, may also arrive around 2042, the team calculates.

    In another Hubble image of the galaxy cluster MACS J0138.0-2155, the cluster split the light from a supernova into three points, SN1, SN2 and SN3. The other two points, SN4 and SN5, are predictions of where the light from the supernova will appear in future years.S. Rodney et al/Nature Astronomy 2021

    The predicted 21-year time delay — from 2016 to 2037 — is a record for a supernova. In contrast, the first gravitational lens ever found — twin images of a quasar spotted in 1979  — has a time delay of only 1.1 years (SN: 11/10/1979).

    Not everyone agrees with Rodney’s forecast. “It is very difficult to predict what the time delay will be,” says Rudolph Schild, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who was the first to measure the double quasar’s time delay. The distribution of dark matter in the galaxy hosting the supernova and the cluster splitting the supernova’s light is so uncertain, Schild says, that the next image of SN Requiem could come outside the years Rodney’s team has specified.

    In any case, when the supernova image does appear, “that would be a phenomenally precise measurement” of the time delay, says Patrick Kelly, an astronomer at the University of Minnesota in Minneapolis who was not involved with the new work. That’s because the uncertainty in the time delay will be tiny compared with the tremendous length of the time delay itself.

    That delay, coupled with an accurate description of how light rays weave through the galaxy cluster, could affect the debate over the Hubble constant. Numerically, the Hubble constant is the speed a distant galaxy recedes from us divided by the distance to that galaxy. For a given galaxy with a known speed, a larger estimated distance therefore leads to a lower number for the Hubble constant.

    This number was once in dispute by a factor of two. Today the range is much tighter, from 67 to 73 kilometers per second per megaparsec. But that spread still leaves the universe’s age uncertain. The frequently quoted age of 13.8 billion years corresponds to a Hubble constant of 67.4. But if the Hubble constant is higher, then the universe could be about a billion years younger.

    The longer it takes for SN Requiem to reappear, the farther from Earth the host galaxy is — which means a lower Hubble constant and an older universe. So if the debate over the Hubble constant persists into the 2030s, the exact date the supernova springs back to life could help resolve the dispute and nail down a fundamental cosmological parameter. More