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    The nearest midsized black hole might instead be a horde of lightweights

    Contrary to a previous report, there’s no evidence of an intermediate-mass black hole in Omega Centauri, the Milky Way’s most massive and luminous globular star cluster, a new study finds. Instead, a hive of much smaller black holes diving into and out of the tightly packed star cluster’s center can explain the movement and distribution of its many ancient stars.

    “What we found in our analysis is that the data favor an extended component [of stellar-mass black holes] as opposed to an intermediate-mass black hole,” says Andrés Bañares-Hernández, an astronomer at the Instituto de Astrofísica de Canarias in La Laguna, Spain. Some 10,000 to 20,000 stellar-mass black holes — adding up to between 200,000 and 300,000 times the mass of the sun — that are spread around the center of the star cluster can explain the observations, he says. More

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    Cocaine in mummified brains reveals when Europeans first used the drug

    Coca leaves have psychoactive and therapeutic propertiesFabiano Sodi/Alamy
    The mummified brain tissue of two people found in a 17th-century crypt in Milan, Italy, contains traces of cocaine, revealing that the drug was being used in Europe 200 years earlier than previously recorded.
    Coca leaves, from which cocaine is derived, have been chewed in the plant’s native South America for thousands of years, but the drug only took off in Europe in the 19th century, when it was chemically isolated from the plant.
    Spanish conquerors learned of the psychoactive and therapeutic properties of coca leaves, but… More

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    A distant quasar may be zapping all galaxies around itself

    One of the farthest known quasars seems to have shut down the creation of new stars in all the galaxies within its vicinity.

    A quasar is a powerful source of light, created by torrid gas orbiting a gargantuan black hole at the center of a galaxy. The intense radiation from one quasar, named VIK J2348-3054, has probably stopped star formation at least 16 million light-years away from itself, astronomer Trystan Lambert and colleagues report in a paper to appear in Astronomy and Astrophysics. More

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    Stonehenge’s altar stone was brought all the way from Scotland

    The altar stone lies inside Stonehenge’s two big rings of stonesGavin Hellier/roberthrding/Getty Images
    A study of the 6-tonne altar stone at the heart of Stonehenge has shown that it was almost certainly brought there from north-east Scotland, much further than any other stone in the megalithic structure.
    “All of us were stunned. We couldn’t believe it,” says geologist Anthony Clarke at Curtin University in Perth, Australia.
    How the altar stone was transported all the way from Scotland to the south of England isn’t known, but it is most likely to have been brought by sea, says Clarke. There is evidence that people at this time were making sea journeys, he says.Advertisement

    Stonehenge is thought to have been built over about 1500 years, starting around 5100 years ago. It consists of an outer circle of large stones weighing around 25 tonnes each, known as sarsens, and an inner ring and altar made of smaller stones generally of around 3 tonnes, known as bluestones. The term bluestone just means any rock that isn’t a sarsen – the bluestones are made of various kinds of rock.
    “The thing that’s unique about Stonehenge is the distance that stones have been transported,” says geologist Richard Bevins at Aberystwyth University, UK. Most stone circles are made from rocks found within a kilometre of the site, says Bevins.
    The source of the sarsens, however, has been traced to the West Woods of Wiltshire, around 25 kilometres from the site. And Bevins’s team has shown that almost all the bluestones come from the Preseli hills in Wales, about 280 kilometres away. One idea is that they were part of an even older Welsh stone monument that was moved.
    The altar stone at Stonehenge is different to the other bluestones. “By the end of 2021, we’d come to the conclusion that the altar stone didn’t match any of the geology that we knew in Wales,” says team member Nick Pearce, also at Aberystwyth University.
    This 5-metre-long stone is embedded in the ground with only one surface showing and is partly covered by two other stones. It is thought to have been put in place about 4500 years ago.
    Stonehenge’s altar stone (embedded in the ground under the other stones) came from north-east ScotlandNick Pearce, Aberystwyth University
    Now, Clarke has taken sophisticated equipment usually used in the mining industry and analysed samples of the altar stone. It is a sandstone, which means it is made of eroded grains of rock that piled up at the bottom of an ancient ocean and eventually stuck together to form a new rock. The age of each grain varies depending on when the rock it eroded from first formed, so different sandstones have a distinctive mix of grains of different ages.
    Clarke analysed individual crystals of the minerals zircon, apatite and rutile within samples of the stone. These minerals contain uranium, which very slowly decays to lead, allowing them to be dated from the ratio of uranium to lead. For instance, the zircon in the stone is between 500 million and 3 billion years old.
    The pattern of ages shows with greater than 95 per cent certainty that the altar stone is Old Red Sandstone from the Orcadian basin in north-east Scotland, says team member Chris Kirkland at Curtin University. This basin was once a massive ancient water body called Lake Orcadie.

    The nearest matching Old Red Sandstone to Stonehenge is 750 kilometres away in the vicinity of Inverness, and the furthest is in the Shetland Islands up to 1000 kilometres away – hence why the team thinks the altar stone was probably transported by sea.
    Glaciers can carry boulders long distances, but the evidence is that during the last glacial period, the flow of ice in the Orcadian region was northwards rather than southwards, says Kirkland.
    So why was the altar stone brought such a long distance? “That is the great unanswerable question,” says Clarke. “All we know is it’s a 6-tonne piece of rock that’s come from 750 kilometres away. That, by itself, tells us an awful lot about the Neolithic society and its connectivity.”
    “What they’ve done is pretty rigorous,” says David Nash at the University of Brighton, UK, whose team identified the precise source of the sarsens in Wiltshire. “It’s a really sound piece of work.”

    Pinning down the source of the altar stone more precisely will be difficult because the Orcadian basin extends over a vast area and is up to 8 kilometres deep, says Nash. “That’s a big, big job, because there’s an awful lot of Old Red Sandstone in northern Scotland.”
    With the sarsens, by contrast, there were fewer potential sources, so locating the exact one was easier, he says.
    Genetic studies have shown that the people who did most of the construction of Stonehenge were largely replaced by a new wave of migrants by about 4000 years ago. This could be because a plague pandemic wiped out a large proportion of Europe’s inhabitants around this time.

    Topics:archaeology/Stonehenge More

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    Why the amazing Altamura Man fossil remains a mystery

    The Altamura Man skeleton in Lamalunga caveCostantino Buzi
    This is an extract from Our Human Story, our newsletter about the revolution in archaeology. Sign up to receive it in your inbox for free every month.
    Have you heard of Altamura Man? Since it was new to me, I’m going to guess that you may be unfamiliar with it. Which is peculiar, because it’s an astonishing specimen.
    To find Altamura Man you would need to travel to Puglia (also known as Apulia) in southern Italy: if you think of Italy as looking like a boot, Puglia is… More

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    Ancient plant artefact reveals humanity’s epic journey to Australia

    Excavations at Mololo cave on the island of Waigeo, where ancient plant resin was foundTristan Russell (The Raja Ampat Archaeological Project)
    A tiny chunk of plant resin shows humans were living on an island in eastern Indonesia at least 55,000 years ago – revealing the likely route that modern humans took when migrating to Australia.
    We know that modern humans journeyed to Australia by heading south-east from mainland Asia, travelling through what is now Indonesia and many other islands of South-East Asia. The exact timing is contested, says Dylan Gaffney at the University of Oxford. Modern genetic evidence suggests humans arrived less than 50,000 years ago, but archaeological evidence points to an earlier arrival, “perhaps 65,000 or even 80,000 years ago”, he says.
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    What is more, the exact route they took is also contested because the geography of the region at the time was different. Earth was in a cold glacial period, so more water was locked up in ice sheets and sea levels were lower, meaning some landmasses that are now islands were connected to continents. In the western part of this region, Borneo, Sumatra and Java were all part of mainland Asia – while in the eastern part, New Guinea was joined to Australia.
    This means there were two possible routes humans could have taken to reach Australia. The northern route heads directly east from Borneo to Sulawesi and on to New Guinea, then south into Australia. The southern route goes via Java, passing through Bali and Timor to northern Australia.
    Possible routes to AustraliaDylan Gaffney/The Raja Ampat Archaeological Project
    To help find out how people made the journey, Gaffney and his colleagues excavated Mololo cave on the island of Waigeo, one of the Raja Ampat islands just west of New Guinea and along the northern route. In the sediments on the cave floor, the team found evidence of human occupation such as charcoal and a few stone flakes.
    Crucially, Gaffney’s team found a piece of resin just 1.4 centimetres across. It has an angular shape, suggesting it was cut from a tree rather than pooling naturally. Radiocarbon dating indicates it is at least 55,000 years old.
    The resin was probably used as fuel for fires, says Gaffney. “It is very flammable and is a good light source in caves.” But there are other possibilities, such as fragrance or adhesive. Whatever its use, it shows that humans were on Waigeo at least 55,000 years ago. “We are demonstrating that people used the northern route,” says Gaffney.
    Modern tree resin can help make fire and ancient resin may have been used in the same wayDylan Gaffney/The Raja Ampat Archaeological Project
    The finding adds to the evidence that people first reached Australia via the northern route, says Kasih Norman at Griffith University in Queensland, Australia. Geographical models always pointed to the northern route because the sea crossings are easier. “You have more water crossings between islands to do along the northern route, but the crossings themselves are shorter,” she says. Furthermore, “you can always see to the next island”.
    However, most archaeological excavations focused on the southern route, says Norman. Only in recent years have researchers like Gaffney begun exploring the northern option.
    One key discovery, published in July, is a 50,000-year-old cave painting of a pig found on Sulawesi, along the northern route. Likewise, a study published in May found that there was no evidence of humans on Timor before 44,000 years ago. Timor lies on the southern route, suggesting this pathway was only used later.

    A final intriguing mystery in all this concerns the absence of the Denisovans – an extinct group of humans known to have lived on mainland Asia – from Australia’s fossil record. Many populations in South-East Asia carry Denisovan DNA: this includes people from Papua New Guinea, who have DNA from two distinct Denisovan groups. That hinted, but didn’t prove, that Denisovans lived on New Guinea. Yet there is no sign of Denisovans on Australia. “As far as we’re aware,” says Norman, “there’s never been anyone else [but Homo sapiens] here.”

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    Some meteors leave trails lasting up to an hour. Now we may know why

    To leave a lasting trail, meteors need to aim low. A new survey of shooting stars shows that meteors that blaze through 90 kilometers up in the sky leave a persistent afterglow, unlike those that burn up at greater heights.

    Meteors are normally blink-and-you’ll-miss-it events. A particle of space dust leaves a fiery trail of light as it zips through the atmosphere, and then it’s gone. But sometimes, a meteor leaves a lingering afterglow. Astronomers have noted these persistent trains for more than a century, but questions remained about their origins. More

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    Spoilt, self-centered and lonely? Examining the only child stereotype

    Michael Kirkham
    I am an only child. Saying this sometimes feels like a confession – not least when people respond with a well-meaning “oh, you don’t seem like it!”. Now, as the mother of a preschooler, I see my daughter navigating the same assumptions. “Does she have older siblings?” one teacher asked recently. “She plays so well with the other kids!”
    If it seems like I am bragging about my (or my daughter’s) behaviour, you will have to excuse me: I am, after all, an only child.
    For over a century, we have been seen as odd, at best; antisocial, neurotic and narcissistic, at worst. “Being an only child is a disease in itself,” declared 19th-century child psychologist Granville Stanley Hall.

    Whether there are actually any differences between the personalities and well-being of singleton children and those with siblings remains a contentious question – one given fresh impetus by the growing trend of one-and-done parenting.
    Single-child families have become more common since the 1970s in high-income countries, including the US and UK, whether “by constraint or by choice”, says éva Beaujouan, a demographer at the University of Vienna, Austria. In Europe, nearly half of all households with children have just one child.
    Despite their growing popularity, one-child families continue to encounter a long-held view that this arrangement is somehow harmful. Fortunately, delving into contemporary research can offer a degree of clarity – and it hints that being an only child can come with surprising outcomes. The findings may offer some reassurance for one-and-done parents and those still debating how many… More