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    The World Before Us review: A gripping account of Earth's other humans

    The Neanderthals, Denisovans and many others once shared Earth with us. What happened – and where are they now? Archaeologist Tom Higham has written a great insider account

    Humans

    24 March 2021

    By Michael Marshall

    Archaeologist Tom Higham, with a skull from a modern humanMark Hardy
    The World Before Us
    Tom Higham

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    Viking
    ASK any well-informed human living up to 40,000 years or so ago if they were the only intelligent being around, and they would have answered, “No”. That is because at that (geologically) recent time, our ancestors would still have been sharing Earth with several other human groups. In a very real sense, we were not alone.
    Today we are. The Neanderthals who roamed Europe and western Asia are long gone. So are the Denisovans of east Asia, the “hobbits” of Flores Island in Indonesia and many more. Who were they? What were they like? What happened to them?
    Archaeologist Tom Higham at the University of Oxford tackles these questions in his first book for a popular audience, The World Before Us: How science is revealing a new story of our human origins. It is a slightly misleading main title because Higham barely discusses the world before Homo sapiens emerged about 300,000 years ago: you won’t find Lucy or any other ape-like australopithecines. But he does deliver on the subtitle, with a fascinating insight into groups belonging to the same Homo genus as us that lived alongside us for much of their existence.
    Higham has been involved in many of the biggest discoveries in human evolution in recent decades. A specialist in dating methods, he helped trace the Neanderthal extinction, studied the mysterious Denisovans, who are mostly known from DNA extracted from bone fragments, and helped push back the date H. sapiens arrived in the Americas.
    “When it comes to what happened to groups like the Neanderthals, Higham wisely embraces nuance”
    The book gets off to a shaky start, as the opening chapters are overstuffed with unnecessary detail that isn’t immediately explained. For example, Higham repeatedly mentions nuclear and mitochondrial DNA, but doesn’t explain them until chapter 5 – although at one point there is an apologetic footnote directing readers to that part.
    However, once past these bumps the book settles into a lively groove. Higham devotes whole chapters, sometimes multiple chapters, to each extinct hominin group. He packs in startling discoveries, impressive insights and the occasional debunking of a foolish idea.
    Higham’s personal involvement means he has lots of good stories. He vividly describes Denisova cave in Siberia, Russia – where the first traces of Denisovans were found – along with its adjacent field camp.
    There are also thumbnail portraits of the scientists involved. A highlight is Higham’s account of the discovery of Denny, a girl who lived in or around Denisova cave, with a Neanderthal mother and a Denisovan father. One of Higham’s students, Samantha Brown (now at the Max Planck Institute for the Science of Human History, Germany), spent weeks testing bone fragments before identifying one that belonged to a hominin.
    Higham reproduces the flurry of excited, expletive-ridden texts he sent after being told the news. The reader gets a real sense of what it is like to “do” science as Higham emphasises Brown’s boring, reward-free slog before she finally struck pay dirt.
    When it comes to the perennial question of what happened to groups like the Neanderthals, Higham wisely embraces nuance and complexity. It is unlikely there is a single explanation for the extinction of such a group as widespread and adaptable as the Neanderthals – and conservation biologists tend to find that species experience a multitude of threats.
    For groups like the Denisovans, of whom we have barely any remains, he refuses to commit himself at all. He knows it is too early to make a big claim about what happened when we don’t even know the extent of their range or what they looked like.
    In any case, many of them haven’t entirely gone. Thanks to interbreeding, the DNA of Neanderthals and Denisovans lives on. In our genes, at least, we still share the world with them.

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    Kate Crawford interview: How AI is exploiting people and the planet

    Beyond the headline breakthroughs, artificial intelligence is a global industrial complex. Having explored its political and social implications, Kate Crawford at Microsoft Research is now focusing on the infrastructure underpinning AI

    Technology

    24 March 2021

    By Timothy Revell

    Rocio Montoya
    ARTIFICIAL intelligence is everywhere these days, from the Alexa virtual assistant in your kitchen to the algorithms that decide on your suitability for a job or a mortgage. But what exactly is it? The definition matters because to a great extent it dictates how we think about AI’s impact.
    If AI is something that outperforms humans by definition, it seems logical to trust it to identify people who should be stopped and searched via facial recognition, say, or to make judgements on which offenders should get probation. If it is solely about algorithms, it becomes a lot easier to sweep aside issues of bias and injustice as mere technical issues.
    Kate Crawford takes a broader view. Co-founder of the AI Now Institute at New York University and a researcher at Microsoft Research and the école Normale Supérieure in Paris, she has spent the best part of two decades investigating the political and social implications of AI. In her new book, Atlas of AI, she also looks at the global infrastructure that underpins the rise of this technology.
    She argues that AI, far from being something abstract and objective, is both material and intrinsically linked to power structures. The way it is made involves extracting resources from people and the planet, and the way it is used reflects the beliefs and biases of those who wield it. Only when we come to terms with this, says Crawford, will we be able to chart a just and sustainable future with AI.
    Timothy Revell: What is AI?
    Kate Crawford: I think of it in three ways. Technically speaking, it is … More

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    Don’t Miss: The Best of World SF, with tales old and new

    Read
    The Best of World SF: Volume 1 contains 26 sci-fi stories, some celebrated and others new, representing 21 countries and five continents. Edited by writer Lavie Tidhar, the collection is a celebration of a truly global genre.

    Read
    Overloaded is science writer Ginny Smith’s exploration of how our lives are influenced by neurotransmitters, the brain chemicals behind everything, from what we remember and who we love to basic drives such as hunger, fear and sleep.
    Pixabay
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    Our Future Planet: Global greenhouse gas removal, the latest in the climate talk series from the UK-based Science Museum Group sees scientists and engineers discuss carbon capture. Watch online at 7.30 pm BST on 31 March.

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    in Space & Astronomy

    A new black hole image reveals the behemoth’s magnetic fields

    Astronomers have gotten their first glimpse of the magnetic fields tangled around a black hole.

    The Event Horizon Telescope has unveiled the magnetism of the hot, glowing gas around the supermassive black hole at the heart of galaxy M87, researchers report in two studies published online March 24 in the Astrophysical Journal Letters. These magnetic fields are thought to play a crucial role in how the black hole scarfs down matter and launches powerful plasma jets thousands of light-years into space (SN: 3/29/19).

    “We’ve known for decades that jets are in some sense powered by accretion onto supermassive black holes, and that the in-spiraling gas and the outflowing plasma are highly magnetized — but there was a lot of uncertainty in the exact details,” says Eileen Meyer, an astrophysicist at the University of Maryland, Baltimore County not involved in the work. “The magnetic field structure of the plasma near the event horizon [of a black hole] is a completely new piece of information.”

    The supermassive black hole inside M87 was the first black hole to get its picture taken (SN: 4/10/19). That image showed the black hole’s shadow against its accretion disk — the bright eddy of superhot gas spiraling around the black hole’s dark center. It was created using observations taken in April 2017 by a global network of observatories, which collectively form one virtual, Earth-sized radio dish called the Event Horizon Telescope (SN: 4/10/19).

    [embedded content]
    Using data from 2017, scientists created the first real picture of the supermassive black hole at the center of galaxy M87. How? We explain.

    The new analysis uses the same observations. But unlike the black hole’s initial portrait, the new image accounts for the polarization of the light waves emitted by gas around the black hole. Polarization measures a light wave’s orientation — whether it wiggles up and down, left and right or at an angle — and can be affected by the magnetic field where the light originated. So, by mapping the polarization of light around the edge of M87’s black hole, researchers were able to trace the structure of the underlying magnetic fields.

    The team found evidence that some magnetic fields loop around the black hole along with the disk of material swirling into it. That’s to be expected because “when gas is rotating, it’s basically able to carry along the magnetic field with it,” says Jason Dexter, an astrophysicist at the University of Colorado Boulder.

    But, he says, “there’s some interesting component of this magnetic field which is not just following the motion of the gas.” At least some of the magnetic field lines are sticking up or down perpendicularly from the accretion disk, or pointing directly toward or away from the black hole, Dexter and colleagues found. These magnetic fields must be very strong to resist being dragged around by the whirl of infalling gas, he says.

    Such strong magnetic fields may actually push back against some of the material spiraling in toward the black hole, helping it resist gravity’s pull, says study coauthor Monika Mościbrodzka, an astrophysicist at Radboud University in Nijmegen, the Netherlands. Magnetic fields pointed up and down from the accretion disk could also help launch the black hole’s plasma jets, by channeling material toward the black hole’s poles and giving it a boost in speed, she says.

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    in Space & Astronomy

    Carbon-ring molecules tied to life were found in space for the first time

    Complex carbon-bearing molecules that could help explain how life got started have been identified in space for the first time.

    These molecules, called polycyclic aromatic hydrocarbons, or PAHs, consist of several linked hexagonal rings of carbon with hydrogen atoms at the edges. Astronomers have suspected for decades that these molecules are abundant in space, but none had been directly spotted before.

    Simpler molecules with a single ring of carbon have been seen before. But “we’re now excited to see that we’re able to detect these larger PAHs for the first time in space,” says astrochemist Brett McGuire of MIT, whose team reports the discovery in the March 19 Science.

    Studying these molecules and others like them could help scientists understand how the chemical precursors to life might get started in space. “Carbon is such a fundamental part of chemical reactions, especially reactions leading to life’s essential molecules,” McGuire says. “This is our window into a huge reservoir of them.”

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    Since the 1980s, astronomers have seen a mysterious infrared glow coming from spots within our galaxy and others. Many suspected that the glow comes from PAHs, but could not identify a specific source. The signals from several different PAHs overlap too much to tease any one of them apart, like a choir blending so well, the ear can’t pick out individual voices.

    Instead of searching the infrared signals for a single voice, McGuire and colleagues turned to radio waves, where different PAHs sing different songs. The team trained the powerful Green Bank Telescope in West Virginia on TMC-1, a dark cloud about 430 light-years from Earth near the constellation Taurus.

    The interstellar cloud TMC-1 (top, black filaments) appears as a dark streak on the sky next to the bright Pleiades star cluster (right)Brett A. McGuire

    Previously, McGuire had discovered that the cloud contains benzonitrile, a molecule made of a single carbon ring (SN: 10/2/19). So he thought it was a good place to look for more complicated molecules.

    The team detected 1- and 2-cyanonaphthalene, two-ringed molecules with 10 carbons, eight hydrogens and a nitrogen atom. The concentration is fairly diffuse, McGuire says: “If you filled the inside of your average compact car with [gas from] TMC-1, you’d have less than 10 molecules of each PAH we detected.”

    But it was a lot more than the team expected. The cloud contains between 100,000 and one million times more PAHs than theoretical models predict it should. “It’s insane, that’s way too much,” McGuire says.

    There are two ways that PAHs are thought to form in space: out of the ashes of dead stars or by direct chemical reactions in interstellar space. Since TMC-1 is just beginning to form stars, McGuire expected that any PAHs it contains ought to have been built by direct chemical reactions in space. But that scenario can’t account for all the PAH molecules the team found. There’s too much to be explained easily by stellar ash, too. That means something is probably missing from astrochemists’ theories of how PAHs can form in space.

    “We’re working in uncharted territory here,” he says, “which is exciting.”

    Identifying PAHs in space is “a big thing,” says astrochemist Alessandra Ricca of the SETI Institute in Mountain View, Calif., who was not involved in the new study. The work “is the first one that has shown that these PAH molecules actually do exist in space,” she says. “Before, it was just a hypothesis.”

    Ricca’s group is working on a database of infrared PAH signals that the James Webb Space Telescope, slated to launch in October, can look for. “All this is going to be very helpful for JWST and the research on carbon in the universe,” she says. More

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    Volcanic eruption may have forced ancient Egyptians to abandon a city

    By Michael Marshall

    Water being pumped out of the gate chamber housing an ancient well in EgyptM. Woźniak
    Ancient Egyptians abandoned one of their coastal cities more than 2000 years ago, when the supply of fresh water dried up. The cause may have been a major volcanic eruption, possibly on the other side of the world, that triggered a severe drought.
    Archaeologists have been excavating the city of Berenike on Egypt’s Red Sea coast on and off since 1994. Berenike was founded between 275 and 260 BC, but was temporarily abandoned sometime between 220 and 200 BC, before being repopulated for many centuries. After Egypt was annexed by the Roman Empire in 30 BC, Berenike became the empire’s southernmost port.

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    Berenike was “a kind of combination of city and military base”, says Marek Woźniak at the Institute of Mediterranean and Oriental Cultures in Warsaw, Poland.
    Since 2014, Woźniak has been excavating the remains of a gate and tower in the fortress wall. With James Harrell at the University of Toledo in Ohio, he has now described a well sunk into the floor of the building. The well still accumulates water today. “It tastes pretty good, although actually a bit salty,” says Woźniak.

    However, the well dried up between 220 and 200 BC, and sand was blown into it by the wind. This sand is preserved in the well, and contains two bronze coins dating from the decades before 199 BC. Elsewhere in the fortress, there are few artefacts from that time, suggesting Berenike was abandoned.
    There must have been a drought lasting several years to cause the well to dry up, says Woźniak. He says the most likely cause is a volcanic eruption. In line with this, a 2017 study led by Jennifer Marlon at Yale University found that, in 209 BC, a volcanic eruption released lots of sulphate aerosols into Earth’s atmosphere. This caused the summer rains over the Nile headwaters to fail. The lack of rain could explain the well drying out, which perhaps helped encourage inhabitants to abandon the city.
    It is unclear which volcano would have been responsible. Woźniak and Harrell suggest four possibilities: Popocatéptl in Mexico, Pelée on the island of Martinique in the Lesser Antilles, Tsurumi or Hakusan, both of which are in Japan.
    Journal reference: Antiquity, DOI: 10.15184/aqy.2021.16 More

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    Silk Road review: The true story of the dark web's illegal drug market

    The wild scheme of Ross Ulbricht, a young physics grad who set up a massive online illegal drugs market, keeps us hooked to the bitter end in Silk Road, a fictionalised version of his story

    Humans

    17 March 2021

    By Linda Marric

    Nick Robinson as Ross Ulbricht, founder of the dark web marketplace Silk RoadVertigo Releasing
    Silk Road
    Tiller Russell

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    Vertigo Releasing,
    streaming from 22 March
    IN OCTOBER 2013, Ross Ulbricht was arrested by the FBI and charged with money laundering, conspiracy to commit computer hacking and conspiracy to traffic narcotics. Two years earlier, Ulbricht had launched the Silk Road, the first modern dark web market, known for selling drugs that are illegal in the US.
    Suddenly, users could order any illicit substance they wanted from dealers online and have it delivered, no questions asked, to their homes by the US Postal Service the very next day.
    Ulbricht’s site operated as a Tor hidden service, making it easier for its users to browse it anonymously and conduct all their transactions using untraceable cryptocurrencies. Within a few months, Ross had amassed a huge following under the pseudonym Dread Pirate Roberts (a reference to The Princess Bride movie) and a small fortune in bitcoin thanks to an article about the site, which appeared in the now defunct Gawker blog.
    But what was the route that took a twentysomething, middle-class physics graduate from Texas to the FBI’s most-wanted list?
    In Silk Road, the movie version of the story, writer-director Tiller Russell (whose catalogue includes Night Stalker: The hunt for a serial killer, a four-part exploration of the crimes of Richard Ramirez) maps out Ulbricht’s trajectory from law-abiding citizen to drug player in this flawed crime story. It is based on “Dead End On Silk Road: Internet crime kingpin Ross Ulbricht’s big fall”, a Rolling Stone article written about Ulbricht by David Kushner.
    The film opens at a branch of the San Francisco Public Library in 2013, where Ulbricht (Nick Robinson) is being trailed by undercover federal agents hoping to catch him red-handed logging onto his site. Then it flashes back to a couple of years before that, to a Texas bar where gaudy libertarian show-off Ulbricht is attempting to smooth-talk his way out of an awkward political exchange with Julia (Alexandra Shipp).
    Soon the two become inseparable, and when he jokingly suggests launching a website from which dealers can easily sell drugs, both Julia and Ulbricht’s best friend Max (Daniel David Stewart) are happy to go along with his wild scheme.
    Although we are cheekily warned from the start that “this story is true. Except for what we made up or changed”, there are clearly some aspects of the tale that are simply there to pad out an otherwise stale and meandering screenplay. For example, a subplot featuring a brilliant turn from Jason Clarke (Zero Dark Thirty) as crooked cybercrime agent Rick Bowden often feels superfluous.
    Robinson gives a suitably nervy and understated performance as the anti-hero you wish you could root for. It is this moral ambiguity that gives the film the edge it needed, but it is a shame that more isn’t made of this by Russell. Elsewhere, Paul Walter Hauser (I, Tonya and Richard Jewell) gives another scene-stealing turn as hapless Utah hacker Curtis Clark Green, Ulbricht’s employee.
    Overall, Silk Road often seems unsure where its sympathies lie, and this is its main problem. Having said that, there is just enough here to keep those who are unfamiliar with the story hooked till the bitter end. Just don’t go expecting anything as good or full of cracking dialogue as David Fincher’s The Social Network or you will be sorely disappointed.

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    Don’t Miss: Rob Dunn on flavour‘s role in human evolution

    Amazon Prime Video
    Watch
    Invincible, available from 26 March on Amazon Prime Video, animates Robert Kirkman’s long-running comic about an ordinary teenager whose father just happens to be Omni-Man, the world’s most powerful superhero.

    Watch
    Rob Dunn, co-author of the new book Delicious with Monica Sanchez, speaks about the deep history of flavour and the role it has played in human evolution. Online from the Royal Institution in London at 7 pm GMT on 23 March.

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    A Thousand Brains: A new theory of intelligence by Jeff Hawkins, inventor and neuroscientist, explains how the brain builds not just one model, but hundreds of thousands of models of everything we know.

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