More stories

  • in

    Prehistoric dart-throwing atlatl weapon even more deadly than thought

    Tests of the prehistoric atlatl on a bison carcass recorded using a high-speed camera show the weapon could be very effective at bringing down large animals by puncturing their vital organs

    Humans

    15 July 2022

    By Jeremy Hsu
    Donny Dust about to test an atlatlDonny Dust
    Tests of a prehistoric dart-throwing weapon have shown it is even more effective than previously thought. The atlatl weapon can puncture vital organs in bison carcasses and travel so far through the body it protrudes from the other side.
    “Some prominent archaeologists are starting to become sceptical that [prehistoric humans] were capable of killing big animals on a regular basis,” says Devin Pettigrew at the University of Colorado Boulder. “But for all intents and purposes, these are highly effective weapons capable of penetrating … More

  • in

    A fast radio burst’s rapid, steady beat offers a clue to its cosmic origin

    An unusual blast of radio waves from deep space had a sense of rhythm. Over the few seconds in December 2019 when the burst was detected, it kept a steady beat. That tempo holds clues to the potential origin of the mysterious outburst, one of a class of flares called fast radio bursts.

    Of the hundreds of previously detected fast radio bursts, most last for mere milliseconds. But this one persisted for roughly three seconds, Daniele Michilli and colleagues report in the July 14 Nature. The burst consisted of multiple brief pulses, repeating about every two-tenths of a second.

    Sign Up For the Latest from Science News

    Headlines and summaries of the latest Science News articles, delivered to your inbox

    Thank you for signing up!

    There was a problem signing you up.

    Scientists have previously observed fast radio bursts that repeat with a delay of minutes or days (SN: 3/2/16). “With this one it was a train of [pulses] one after the other, a heartbeat, like, ‘boom boom boom boom,’” says Michilli, an astronomer at MIT.

    That makes this fast radio burst very special, says astrophysicist Bing Zhang of the University of Nevada, Las Vegas, who was not involved with the research. Compared with other fast radio bursts, “this is a different animal.”

    Scientists still don’t know how fast radio bursts are generated, but evidence has been building that they are associated with ultradense, spinning dead stars called neutron stars and, in particular, highly magnetic neutron stars called magnetars (SN: 6/4/20).

    The steady repetition rate hints at what may have caused this particular blast, discovered by the Canadian Hydrogen Intensity Mapping Experiment, a radio telescope in British Columbia.

    Only certain types of cosmic processes produce such metronome-like signals. Neutron stars, for example, can appear to pulse as they spin, because they emit beams of radio waves that can sweep past Earth at regular intervals. Neutron stars tend to have tempos similar to that of the pulsating fast radio burst. But that burst was much more luminous than normal neutron star pulses, suggesting some unknown process would need to have amped up the emission.

    Another idea is that large outbursts on magnetars could cause starquakes that jostle those stars’ solid crusts, generating regular barrages of radio waves. The rhythmic burst’s pulsing “is sort of consistent with a frequency with which we expect that magnetars could be shaking,” says astrophysicist Cecilia Chirenti of the University of Maryland in College Park, who was not involved with the new study.

    Or the pulsing might result from two neutron stars that orbit one another. Outbursts could occur at regular points in that orbit, when the magnetic regions that surround each neutron star interact.

    Scientists don’t know if all fast radio bursts are generated in the same way. An outlier like this one might have a different origin story than a more standard, one-off blast. That means it’s hard to make conclusions about other fast radio bursts, Zhang says. “Whatever we can derive from this one, I would not easily extrapolate to the other guys.” More

  • in

    When did humans start making art and were Neanderthals artists too?

    By Michael Marshall
    Painting of a bison from the Altamira cave complexNational Museum and Research Center of Altamira/CC BY-SA 3.0
    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.
    When we think about art, we tend to think about the relatively recent past. The famous cave art in Lascaux, France, is often said to be around 17,000 years old. A second French cave, Chauvet, has similarly spectacular paintings that have been dated to 30,000 or so years ago – but that date is controversial, with some archaeologists saying the paintings are just too good to be that old. When you consider that our species, Homo sapiens, is probably more than 300,000 years old, and that our genus Homo has been around for more than 2 million years, those few tens of thousands of years are a vanishingly short span of time. Why did humans start painting so late in the day, and why didn’t other hominins like Neanderthals do it?
    Well, it’s possible that we actually did make art much earlier than that, and that Neanderthals and other groups such as Denisovans did the same. There are two barriers to demonstrating this: prejudice against the idea that other hominins could express themselves symbolically, and issues with the physical evidence.Advertisement
    In early June, I spent a few days with holidaymakers on a New Scientist Discovery Tour focused on prehistoric rock art in the caves of northern Spain. The centrepiece of the tour was Altamira, the first place where prehistoric European cave art was found – back in 1879, long before Lascaux and Chauvet were discovered.
    How old is Europe’s cave art?
    As part of my preparation, I tried to find out as much as I could about each of the caves on the itinerary. But I kept having the same problem: figuring out how old the artworks were. In Altamira, that’s because the paintings spanned a long period: one is 36,000 years old, another 22,000, while the artefacts in the cave are as little as 14,000 years old.
    But in other cases, the dates for each artwork varied. Take Hornos de la Peña cave, for instance. It has a great many engravings of animals, drawn with striking anatomical accuracy. Spain’s official tourism website says they were created in two phases, one dating back at least 18,000 years and another close to 15,000 years ago. However, a 2014 study lists the dates that have been obtained for the artworks, and they range from around 10,000 years ago to more than 30,000 years ago. Part of the problem is that the cave has been interfered with: it was used as a shelter in the Spanish civil war, and was further altered to enable tourists to visit.
    Similarly, El Pindal cave has lots of pictures of horses and bison, with a fish and a mammoth thrown in. Once again, there is no definitive date. The same Spanish tourism website has them at between 13,000 and 18,000 years old, while a book chapter from 2007 identifies El Pindal as one of several caves in the region where the dates of the art are problematic.
    I spoke to Alistair Pike at the University of Southampton in the UK, who has studied the age of cave art, to clarify the dates of the paintings. He told me that only “a tiny, tiny proportion” of cave art has been reliably dated.
    Some of the reasons for this are good. Until recently, the main method of finding the age of a piece of cave art was radiocarbon dating. This is inherently destructive – you have to scrape off a sample – and understandably the custodians of the caves are slow to give permission. Furthermore, carbon dating only works if there is organic material like charcoal in the art; for engravings, and anything painted solely with minerals, it’s useless.
    Unfortunately, there is also a bad reason not to perform carbon dating. “People had assumed that they could tell the age of cave paintings by the style in which it was depicted,” says Pike. Ever since the first prehistoric art was found in the late 1800s, there has been a sense that art should evolve linearly: the oldest pieces should be extremely simple and abstract, with later ones becoming more technically skilled and creative. Hence the scepticism over Chauvet, despite the paintings having been carbon-dated.
    This line of thinking was comprehensively exposed in a 2011 study by April Nowell and Genevieve von Petzinger, then both at the University of Victoria in British Columbia, Canada. By asking experts on each cave to explain why they believed the artworks to be certain ages, Nowell and von Petzinger discovered an enormous loop of circular logic. Artworks in separate caves were assumed to be the same age because they looked similar, so cave A’s art was so many thousand years old because it looked like cave B’s art – except that the experts on cave B were basing their own age estimates on cave A.
    “It all went round in a really big circle,” says Pike. “It’s one of the most brilliant pieces of work I’ve ever seen.”
    Paleolithic cave art in northern SpainYvon Fruneau/UNESCO
    Were Neanderthals artists too?
    If a lot of the given ages are spurious, our ideas about who made the art are also spurious.
    A succession of hominins have lived in western Europe and might theoretically have made the region’s cave art. Modern humans are the most recent inhabitants, having permanently settled in the region around 45,000 years ago after emerging from Africa. Before that, Europe and western Asia were inhabited by Neanderthals for hundreds of thousands of years. And before that, other hominins like Homo antecessor were around.
    If all the cave art in western Europe is less than 30,000 years old, it could only have been made by our species. But in the cases where researchers like Pike have managed to get reliable dates, that hasn’t always proved true.
    Back in 2012, Pike’s team showed that a red dot on the wall of El Castillo cave in northern Spain was at least 40,800 years old. That was old enough to be borderline: Neanderthals were still around, so they could have made the dot.
    The team did this using uranium-thorium dating. This doesn’t find the age of the art itself, but the age of a thin mineral overlaying it. These layers form when water trickles over the cave wall, depositing minerals that gradually build up. The dating technique tells us when the mineral layer formed, giving a minimum age for the art.
    In a 2018 follow-up, Pike’s team dated the art in three more Spanish caves. The first was La Pasiega, which is in the same hill as El Castillo. A symbol made of red lines turned out to be at least 64,800 years old. The second was Maltravieso in western Spain, where a hand stencil proved to be at least 66,700 years old, making it the oldest cave art known in the world. Finally, some of the red paint on stalagmites in Ardales cave on Spain’s southern coast turned out to be at least 65,500 years old.
    When I mentioned these dates to the holidaymakers in northern Spain, there were audible gasps. They were a knowledgeable and engaged audience, but these results and their transformational significance hadn’t sunk in. If the art is really this old, the most sensible explanation is that Neanderthals made it.
    In line with this, Pike points to other sites with evidence of symbolic behaviour by Neanderthals, going way back into prehistory, but which were previously dismissed. In Bruniquel cave in southern France, there is a stone circle made from broken stalagmites that is 175,000 years old. Pigments on shells in Aviones cave in southern Spain are 115,000 years old. There is evidence of Neanderthals collecting ochre, a red pigment often used in cave paintings , at Maastricht-Belvédère in the Netherlands at least 200,000 years ago.
    Marshall’s First Law
    Pike’s team has struggled to do additional dating in the past few years, partly because of the covid-19 pandemic and partly because “archaeologists who don’t want Neanderthals to have painted have basically banned us from taking samples”. However, he hopes that other groups will have more luck, eventually building up a rigorous timeline of cave art. He suspects art-making may stretch back to the unknown common ancestor we shared with Neanderthals, hundreds of thousands of years ago.
    Art may be another example of what in a previous newsletter I self-aggrandisingly called Marshall’s First Law: Never be surprised when something turns out to be older than you thought. A recent study used artificial intelligence to identify hidden evidence of controlled fires at a site in Israel from 1 million years ago – hundreds of thousands of years before evidence for fire use becomes widespread. I will lay odds that painting and symbolic expression will also turn out to be much older, once we start properly looking.
    The fundamental difficulty we face is that art is fragile. The stuff in caves has survived because these were very stable environments – especially if the entrance collapsed, keeping people out for millennia. But maybe people were expressing themselves all over the place, as can be seen in the Côa valley in Portugal where there are thousands of open-air engravings from at least 10,000 years ago. It’s just that most outdoor art has long since eroded away. “The landscape was full of symbols,” says Pike, “and very few of them survived.”

    More on these topics: More

  • in

    Ancient DNA adds to evidence for Native Americans' east Asian ancestry

    Genetic analysis of a woman’s skull from 14,000 years ago found in south-west China suggests she was related to an ancient population that migrated to North America from east Asia

    Humans

    14 July 2022

    By Carissa Wong
    Side view of an ancient skull found in Red Deer Cave, ChinaXueping Ji
    Ancient DNA from a 14,000-year-old skull found in south-west China reveals that the individual was a member of our species, Homo sapiens, and had genetic ties to the east Asian ancestors of Native Americans.
    The cranium, which belonged to an individual known as Mengzi Ren, was unearthed in 1989 in Red Deer Cave in the Yunnan province of China. Since then, it has been debated whether the skull belonged to an archaic human, such as a Neanderthal or Denisovan, or a member of our species.
    Now, Bing Su at the Kunming Institute of Zoology at the Chinese Academy of Sciences and his colleagues have established that Mengzi Ren was a female H. sapiens by analysing ancient DNA from the specimen. The team sequenced a fraction of the total genome, just 100 million DNA bases, but this was enough to establish the individual’s species-level identity.Advertisement
    “It was a really exciting moment,” says Su. “It is difficult to find ancient DNA in such a sample. After three years of trying to extract DNA from around 100 spots on the cranium, we found ancient DNA that we could sequence.”
    By then comparing the genome of Mengzi Ren with ancient genomes from around the world, the team revealed genetic similarities between the individual and living people of east Asian ancestry, as well as Native American people. This suggests Mengzi Ren was related to ancient populations in east Asia that contributed to Native American ancestry.
    The east Asian ancestry of Native Americans has previously been inferred by analysing the DNA of living people.
    “This is the first time we have sequenced an ancient east Asian genome from the time when people were migrating into America, helping to confirm the east Asian ancestry of Native Americans,” says Su.

    Based on this genetic analysis, the researchers speculate that some of these ancestors of Native Americans may have travelled north along the coastline of present-day eastern China, as well as through the Japanese islands, before crossing into America from Siberia.
    “This work is very exciting, as it shows how the settlement of east Asia is linked to the peopling of America,” says Tábita Hünemeier at the Institute of Evolutionary Biology, Spain.
    She adds that there is also evidence that some members of the founding population that entered the Americas dispersed westwards back into east Asia. “This could be [another] explanation for the presence of a relationship between Mengzi Ren’s ancestry and ancient Native Americans,” she says.
    Journal reference: Current Biology, DOI: 10.1016/j.cub.2022.06.016
    Sign up to Our Human Story, a free monthly newsletter on the revolution in archaeology and human evolution

    More on these topics: More

  • in

    Would you sacrifice five lobsters to save the life of a cat?

    Feedback investigates weird trolley problems, the Palaeolithic cannibal diet, fussy otters and microrobot dentistry

    Humans

    13 July 2022

    Josie Ford
    Trolley trouble
    It is the morning rush, the tram is full to bursting and Feedback wonders who to sacrifice for the greater good. Pulling an imaginary lever will prevent a crash and divert us onto a track with just one individual tied to it? Eminently reasonable.
    This brand of thought experiment, first formulated in a 1967 philosophy paper by Philippa Foot, gets a video-game outing on developer Neal Agarwal’s Absurd Trolley Problems website.
    Following a tip from Motherboard, Feedback visited the site and rattled through some classic trolley problems, only to be transported to some very strange territory indeed. … More

  • in

    Black Hole Symphony preview: Orchestral work blends science with music

    An extraordinary piece called Black Hole Symphony translates cutting-edge research on black holes into an electro-symphonic score with five movements

    Humans

    13 July 2022

    By Bethan Ackerley
    David Ibbett set out to capture black hole complexity in soundRajarajan Palanimurugan
    Black Hole Symphony
    David Ibbett
    Museum of Science in Boston, Massachusetts, and Multiverse Concert Series On 28 July and 25 August
    TAKE a second to imagine the sound of the cosmos. What comes to mind? Is it the howling winds of a far-flung exoplanet? The roiling eruptions at the surface of the sun? Or simply the nothingness that would greet you in the boundless vacuum of space?
    In the absence of recordings of the “real” sounds of our universe, you … More

  • in

    Don't Miss: Find out about the handshake, humanity's oldest greeting

    Anna Shvets/Pexels
    Visit
    The Handshake is over 7 million years old, says palaeoanthropologist, explorer and comic Ella Al-Shamahi. She will explain the secrets of this most ancient and universal greeting at the Royal Institution, London, at 7pm BST on 21 July.

    Read
    Why Sharks Matter to us, the oceans and the marine economy is a subject of concern for David Shiffman, at the University of Arizona. Saving the imperilled predator will require a serious rethink of its image. Available to buy in the UK from 19 July.
    Chris Reeve
    Visit
    The Future of Ageing makes the case … More

  • in

    The Metaverse review: Tech CEO Matthew Ball tangles with digital space

    Matthew Ball is one of the first to write a book about that elusive dream of the future, the metaverse, and it is excellent – in parts

    Humans

    13 July 2022

    By Chris Stokel-Walker
    We hear a lot about the potential of the metaverse, but what is it and when will it arrive?Rocklights/Alamy
    The Metaverse Matthew Ball
    Liveright
    BILLIONS of dollars and millions of hours have been committed to the metaverse, the buzzy vision of a digital world that promises to transform human life. Yet for all the hype, we have yet to pin down exactly what it will be and why it will matter.
    One of the first to take a stab at explaining it is Matthew Ball, CEO of US venture capital fund, … More