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    Jungle review: How tropical forests helped shape human evolution

    By Michael Marshall

    FOR many of the people reading this, tropical forests are remote places. A few may have visited the Amazon on holiday, or ventured into the Bornean rainforests to see orangutans, but for most, tropical forests seem far removed from everyday life.
    In Jungle, his first book for a general audience, archaeologist Patrick Roberts sets out to tear down the barriers and show us how our lives are intertwined with tropical forests, “to convince you that the history of tropical forests is your history too”.
    To do so, Roberts has written a history of the world according to the tropics and their jungles. He begins with the first land plants and the origins of trees, sketching how they affected the dinosaurs, early mammals and first primates.
    The middle third of the book is devoted to the role of tropical forests in human evolution. A key message is that tropical forests aren’t inhospitable: people have lived in them for hundreds of thousands of years. Roberts attacks the long-standing idea that our ancestors left the trees to live on grasslands. Early hominins clearly spent less time up trees than apes such as chimpanzees, but the evidence suggests that our ancestors lived in many places, from the most open savannah to dense forests. More recently, people living in tropical forests have built city-like settlements, as in the Amazon.
    Roberts moves on to document how the European empires of the past few centuries wrought havoc on the people and ecosystems of the tropics: for instance, by setting up the global trades in sugar and rubber, and exploitative labour systems such as slavery on which they relied. He brings the story up to date by outlining the multiplying threats the forests face from climate change, agriculture and wildfires, ending with pleas for their preservation. If we don’t save the tropical forests, warns Roberts, “climate change, declining food sources, economic catastrophe, political instability, mass migration and an explosion of pandemic diseases will very soon be knocking at your own door”.
    In short, Jungle is enormously ambitious for a first popular book: it spans hundreds of millions of years and ranges across many disciplines. Does Roberts pull it off? Sort of.
    On an intellectual and factual level, he unquestionably succeeds. Jungle is deeply researched, and moves with great skill from ecology and evolution to history and politics. Roberts handles them deftly, rarely putting a foot wrong.
    Where the book does fall down is its writing style. This is so dry and complicated it might as well be an academic text. Sentences routinely run over five lines and paragraphs sprawl over whole pages. Vast arrays of facts and figures are hurled at the reader, largely unleavened by humour, anecdote or anything else.
    This is compounded by a generally grim tone. Even the early chapters on evolution and dinosaurs, in which you might expect joy, thrills or awe before the serious stuff kicks in, are tough going. And the final five chapters, where Roberts outlines how modern capitalism abused tropical forests and its peoples, are an almost unbearable trudge through what feels like an endless series of atrocities.
    “Jungle is enormously ambitious for a first popular book: it spans millions of years and many disciplines”
    I am not suggesting Roberts should have dialled back his message: why should he, when he is so plainly correct? Moreover, some readers may not mind the style, while students looking for a panoramic and detailed survey of tropical forests will get a lot out of Jungle. But its difficult style and dourness will limit the appeal, which is a shame because its message should be heard.
    For me, Jungle‘s biggest problem is that while it does a superb job of conveying the factual and rational reasons why we should all care about tropical forests, it doesn’t make you feel it in your bones.

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    Don't Miss: Biohackers returns to Netflix for season 2

    Netflix
    Watch
    Biohackers returns to Netflix for a second season, following a group of students at a German university caught up in the moral and ethical issues around a powerful gene-editing technology. From 9 July.

    Read
    Our Biggest Experiment, by campaigner and science communicator Alice Bell, is the one we have been conducting on our own climate. She chronicles centuries-old attempts to acquire and manage the energy we need.Advertisement
    AIG/THE FARM 51
    Play
    Chernobylite – released early on Steam, with the complete version out later this month – is a scary survival game set in a beautiful and accurate 3D-scanned recreation of the exclusion zone around the Chernobyl nuclear power station. More

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    A Psalm for the Wild-Built by Becky Chambers is joyful sci-fi reading

    The relationship between a robot and a monk is at the heart of a new bookZoonar GmbH/Alamy
    A Psalm for the Wild-Built
    Becky Chambers
    Tor.comAdvertisement

    I READ a lot of sci-fi and, my, the future can be grim at times. Whether it is characters dealing with alien invasions, technology gone wrong or the ravages of climate change, most modern books in the genre are dour affairs, in stark contrast to the “golden age” sci-fi of the 1940s and 50s, when unrealistic techno-utopianism ruled.
    But it isn’t all bad. Increasingly, authors are writing “hopepunk” stories (a slightly cringeworthy term inspired by cyberpunk) that weaponise optimism, according to one Vox journalist.
    At the forefront of this subgenre is Becky Chambers, award-winning author of the Wayfarers series. But unlike the golden age stories, Chambers’s characters live complex lives and know that not all problems can be tackled with the wave of a plot-solving gizmo. Instead, they rely on relationships to succeed, picking each other up and dusting themselves down in the face of adversity.
    The Long Way to a Small, Angry Planet, the first book in the series, details the adventures of the crew of the ship Wayfarer. As the title suggests, it is much more about the journey than the destination. In a way, not a lot happens, but all the characters are changed by their interactions with one another.
    My favourite character in the book is the charming and tragic Dr Chef (yes, he is the ship’s doctor and chef), one of the last of an alien species called Grum, which resemble a kind of six-limbed otter and gradually change biological sex over their lifetime.
    This is just one example of the incredibly diverse cast of aliens that populate the Wayfarers books, which share a universe but mostly stand alone. There are Aeluons, who communicate by flashing colours on their faces, and the reptilian Aandrisk, whose society is influenced by the fact they lay eggs – children are normally the result of casual sex, and aren’t reared by their biological parents.
    There are also artificial intelligences that run ships and other hardware, but it is illegal to upload an AI to a humanoid robot. This is key in the second book, A Closed and Common Orbit, which is a fantastic examination of identity and autonomy.
    Chambers’s latest, the novella A Psalm for the Wild-Built, takes place in a new continuity outside the Wayfarers universe, but shares much of its DNA. It is set on a moon called Panga where humans realised that their sprawling, oil-burning factories were unsustainable and set up a vast rewilding project. “It was a crazy split, if you thought about it: half the land for a single species, half for the hundreds of thousands of others,” writes Chambers. “Finding a limit they’d stick to was victory enough.” Around the same time, robots became sentient and withdrew to the new wilderness, with humans promising to leave them alone.
    The book is set some time after this Transition, and follows a tea monk, Sibling Dex, who goes from settlement to settlement as a travelling salesperson-slash-roaming therapist. Despite bringing joy and comfort to those visited, Dex is unsatisfied and heads out into the wilds, looking for a new purpose – eventually making contact with a robot, Mosscap, the first time humans and robots had met in centuries.
    The heart of the book is the relationship between the two and the way they support each other. It is a joyful experience and, as with all of Chambers’s books, I was left with a warm, fuzzy feeling inside.

    Jacob also recommends…
    TV
    Legends of Tomorrow
    This show about time-travelling superheroes embraces the joy of being silly, and it is now one of my favourites. A recent episode has them meet David Bowie in 1970s London and find Spartacus on a spaceship.
    Book
    Revenger
    Alistair Reynolds
    The first novel in a trilogy sees sisters Adrana and Fura Ness join the crew of the Revenger, led by the space pirate Captain Rackamore, for swashbuckling sci-fi.

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    New fossil finds show we are far from understanding how humans evolved

    Chuang Zhao
    LAST week saw the announcement of not one but two groups of ancient humans, both new to science, and there is no reason to think the discoveries will stop any time soon.
    In Israel, a team of researchers discovered bones from a member of a population that apparently lived in the area between 420,000 and 120,000 years ago. These hominins, which the team calls Nesher Ramla Homo, looked a bit like the Neanderthals, and the team claims that members of the new-found group were the Neanderthals’ ancestors. Not everyone agrees, however, and other interpretations have already been … More

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    The 7 primes of life: Why each decade comes with its own superpowers

    You might think we peak in our 20s or 30s before enduring a slow decline, but each era of our lives brings new strengths – even old age. Here’s how to make the most of them

    Humans

    30 June 2021

    By David Robson

    Matt Murphy

    WHETHER on page, stage or screen, the story of human health and happiness is often presented as an inevitable arc between birth and death. William Shakespeare captured this best with his “seven ages of man” speech. We enter the world “mewling and puking” as an infant, pass through the awkwardness of childhood and adolescence into our physical and mental prime, before a slow decline.
    Until recently, science appeared to confirm this view. For many abilities, we seemed to reach our peak well before midlife. But it is now becoming clear that this picture is far too simplistic. Childhood and adolescence may offer the most rapid periods of development, but our brains can change in positive ways throughout life, with some important cognitive skills continuing to improve into our 50s, 60s and 70s. “The whole idea that the brain is fully mature at age 25 is a joke,” says Daniel Romer, a psychologist at the University of Pennsylvania.
    Nor does our fitness simply rise, peak and fall in a curve. While 20-somethings may win a sprint, performance in many other sports can reach a high later in life. That’s not to mention factors like emotional well-being and mental discipline, which rise and fall in unexpected patterns. And despite nostalgia for the joys of youth, for most of us, our happiest days are actually yet to come.
    By learning to recognise these patterns, we can find better ways to nurture our growth and embrace the opportunities available at each stage of life. So what, based on science, are the seven ages of you? And how can you make the most of … More

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    This moon-sized white dwarf is the smallest ever found

    Only a smidge bigger than the moon, a newfound white dwarf is the smallest of its kind known. 

    The white dwarf, a type of remnant left behind when certain stars peter out, has a radius of about 2,100 kilometers, researchers report June 30 in Nature. That’s remarkably close to the moon’s approximately 1,700-kilometer radius. Most white dwarfs are closer to the size of Earth, which has a radius of about 6,300 kilometers.

    The white dwarf’s small girth means, counterintuitively, that it is also one of the most massive known objects of its kind, at about 1.3 times the sun’s mass. That’s because white dwarfs shrink as they gain mass (SN: 8/12/20).

    “That’s not the only very amazing characteristic of this white dwarf,” astrophysicist Ilaria Caiazzo of Caltech said June 28 in an online news conference. “It is also rapidly rotating.”

    The white dwarf spins around approximately once every seven minutes. And it has a powerful magnetic field, more than a billion times the strength of Earth’s. Caiazzo and colleagues discovered the unusual stellar remnant, dubbed ZTF J1901+1458 and located about 130 light-years from Earth, using the Zwicky Transient Facility at Palomar Observatory in California, which searches for objects in the sky that change in brightness.

    The white dwarf probably formed when two white dwarfs orbited one another and merged to create a single white dwarf with an extra-large mass and extra-small size, the team says. That convergence would also have spun up the white dwarf and given it a strong magnetic field.

    This white dwarf is living on the edge: If it were much more massive, it wouldn’t be able to support its own weight, causing it to explode. Studying such objects can help scientists understand the limits of what’s possible for these dead stars. More

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    Earliest known bubonic plague strain found in 5000-year-old skull

    By Adam Vaughan

    The skull of a young man thought to have died from plague 5000 years agoDominik Göldner, BGAEU, Berlin
    The bacterium behind the Black Death, which wrought devastation in medieval times, has been found in the skull of a man who lived 5000 years ago in what is now Latvia, making it the earliest known plague strain.
    Analysis of ancient DNA in the hunter-gatherer’s skull suggests that the strain of Yersinia pestis, which causes the bubonic plague, was less transmissible and harmful than later versions, say Ben Krause-Kyora at Kiel University, Germany, and his colleagues. The lack of the bacteria in three other people buried next to the man, dubbed RV 2039, is one hint of a less deadly disease, says Krause-Kyora.
    The apparent lower virulence leads the team to suggest that the plague wasn’t to blame for the decline of European people between 5000 and 6000 years ago, as claimed by a 2018 paper looking at Swedish farmers’ genomes.Advertisement
    “There’s an ongoing discussion as whether Y. pestis played a big role in the Neolithic decline,” says Krause-Kyora. “Our hypothesis is really contradicting the one before. It was maybe a more chronic, more omnipresent infection. It caused, for sure, some deaths, but it’s maybe not as severe as it became in the Middle Ages.”

    Nonetheless, the high abundance of the bacteria found in the skull of the man, who was probably aged between 20 and 30 when he died, implies he succumbed to the plague, says Krause-Kyora. The man may have been bitten by a rodent such as a beaver, which are known to carry Y. pestis.  Remains of the animals have been found at the same site by the river Salaca in Latvia.
    The evidence points to the plague spreading from animal to human at the time, rather than human to human, says Krause-Kyora. The bacteria hadn’t yet gained the genetic mutation that enables fleas to carry it, and which allowed it to infect and kill so many people centuries later.
    “To have a close look at the early evolution of this deadly pathogen is really interesting,” says Krause-Kyora. “We see it was more chronic and harmless in the beginning before it became a more deadly disease.”
    However, Simon Rasmussen at the University of Copenhagen, Denmark, says the evidence is weak for the claim the plague was milder 5000 years ago. “There are no new results to substantiate these claims and therefore it remains a hypothesis,” he says. Rasmussen also believes the new study doesn’t invalidate the case he and his colleagues put forward in 2018, of the plague driving the Neolithic decline.
    “The individual does in fact overlap with the Neolithic decline and very likely died from the plague infection. We know that large settlements, trade and movement happened in this period and human interaction is therefore still a very plausible cause of the spread of plague in Europe at this time,” he says.
    Mark Achtman at the University of Warwick, UK, says the team’s interpretations of the plague’s epidemiology appear speculative. “The reasons for epidemic and pandemic outbreaks are unlikely to be found in the bacterial genomes, so ancient DNA of single genomes is not going to help,” he says.
    Journal reference: Cell Reports, DOI: 10.1016/j.celrep.2021.109278
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    Gravitational waves reveal the first known mergers of a black hole and neutron star

    Caught in a fatal inward spiral, a neutron star met its end when a black hole swallowed it whole. Gravitational ripples from that collision spread outward through the cosmos, eventually reaching Earth. The detection of those waves marks the first reported sighting of a black hole engulfing the dense remnant of dead star. And in a surprise twist, scientists spotted a second such merger just days after the first.

    Until now, all identified sources of gravitational waves were twos of a kind: either two black holes or two neutron stars, spiraling around one another before colliding and coalescing (SN: 1/21/21). The violent cosmic collisions create waves that stretch and squeeze the fabric of spacetime, undulations that can be sussed out by sensitive detectors.

    The mismatched pairing of a black hole and neutron star was the final type of merger that scientists expected to find with current gravitational wave observatories. By pure coincidence, researchers spotted two of these events within 10 days of one another, the LIGO, Virgo and KAGRA collaborations report in the July 1 Astrophysical Journal Letters.

    Not only have unions between black holes and neutron stars not been seen before via gravitational waves, the smashups have also never been spotted at all by any other means.

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    “This is an absolute first look,” says theoretical physicist Susan Scott of the Australian National University in Canberra, a member of the LIGO collaboration.

    The result adds another tick mark to the tally of new discoveries made with gravitational waves. “That’s worth celebration,” says astrophysicist Cole Miller of the University of Maryland in College Park, who was not involved with the research. Since the first gravitational waves were detected in 2015, the observatories keep revealing new secrets. “It’s fantastic new things; it’s not just the same old, same old,” he says.

    Signs of the black hole-neutron star collisions registered in the LIGO and Virgo gravitational wave observatories in 2020, on January 5 and January 15. The first merger consisted of a black hole about 8.9 times the mass of the sun and a neutron star about 1.9 times the sun’s mass. The second merger had a 5.7 solar mass black hole and a 1.5 solar mass neutron star. Both collisions occurred more than 900 million light-years from Earth, the scientists estimate.

    To form detectable gravitational waves, the objects that coalesce must be extremely dense, with identities that can be pinned down by their masses. Anything with a mass above five solar masses could only be a black hole, scientists think. Anything less than about three solar masses must be a neutron star.

    One earlier gravitational wave detection involved a black hole merging with an object that couldn’t be identified, as its mass seemed to fall in between the cutoffs that separate black holes and neutron stars (SN: 6/23/20). Another previous merger may have resulted from a black hole melding with a neutron star, but the signal from that event wasn’t strong enough for scientists to be certain that the detection was the real deal. The two new detections clinch the case for black hole and neutron star meetups.

    One of the new events is more convincing than the other. The Jan. 5 merger was seen in just one of LIGO’s two gravitational wave detectors, and the signal has a relatively high probability of being a false alarm, Miller says. “If this were the only event, then you would not be as confident.” The Jan. 15 event, however, “seems pretty solid,” he says.

    Epic rendezvous between neutron stars and black holes happen regularly throughout the cosmos, the detections suggest. Based on the pace of detections, the researchers estimate that these events take place about once a month within 1 billion light-years of Earth.

    [embedded content]
    In a newly reported class of cosmic smashup, a neutron star (apparent in orange in this computer simulation, after the video zooms in) and black hole (dark gray) spiral inward, producing gravitational waves (blue) in a dance that ends when the black hole swallows the neutron star.

    Scientists don’t yet know how neutron stars and black holes come to meet up. They might form together, as two stars that orbit one another until both run out of fuel and die, with one collapsing into a black hole and the other forming a neutron star. Or the two objects might have formed separately and met up in a crowded region packed with many neutron stars and black holes.

    As a black hole and neutron star spiral inward and merge, scientists expect that the black hole could rip the neutron star to shreds, producing a light show that could be observed with telescopes. But astronomers found no fireworks in the aftermath of the two newly reported encounters, nor any evidence that the black holes deformed the neutron stars.

    That could be because in both cases the black hole was significantly larger than the neutron star, suggesting that the black hole gulped down the neutron star whole in a meal worthy of Pac-Man, Scott says.

    If scientists could spot a black hole shredding a neutron star in the future, that could help researchers pin down the properties of the ultradense, neutron-rich material that makes up the dead stars (SN: 4/20/21).

    In past detections of gravitational waves, the Advanced Laser Interferometer Gravitational-Wave Observatory, or LIGO, based in the United States, has teamed up with Virgo, in Italy. The new observations are the first to include members of a third observatory, KAGRA, in Japan (SN: 1/18/19). But the KAGRA detector itself didn’t contribute to the results, as scientists were still preparing it to detect gravitational waves at the time. LIGO, Virgo and KAGRA are all currently offline while scientists tinker with the detectors, and will resume their communal search for cosmic collisions in 2022. More