Recent discoveries of fossils of ancient human relatives in southern Africa are disrupting our long-held ideas of the origins of humankind. Two of these discoveries, Australopithecus sediba and Homo naledi, represent significant contributions to this shakeup of our family tree. And there’s much more to come, as Berger explains in this interview with New Scientist […] More
Richard Dawkins is one of the world’s most famous scientists, a best-selling author – and a hugely controversial figure. His works on evolutionary biology inspired millions, but his bestselling book The God Delusion started a new phase of his career as an outspoken critic of all things religious. We met him at his home in Oxford to find out more. More
The closest cluster of stars to Earth is falling apart and will soon die, astronomers say.
Using the Gaia spacecraft to measure velocities of stars in the Hyades cluster and those escaping from it, researchers have predicted the cluster’s demise. “We find that there’s only something like 30 million years left for the cluster to lose its mass completely,” says Semyeong Oh, an astronomer at the University of Cambridge.
“Compared to the Hyades’ age, that’s very short,” she says. The star cluster, just 150 light-years away and visible to the naked eye in the constellation Taurus, formed about 680 million years ago from a large cloud of gas and dust in the Milky Way.
Stellar gatherings such as the Hyades, known as open star clusters, are born with hundreds or thousands of stars that are held close to one another by their mutual gravitational pull. But numerous forces try to tear them apart: Supernova explosions from the most massive stars eject material that had been binding the cluster together; large clouds of gas pass near the cluster and yank stars out of it; the stars themselves interact with one another and jettison the least massive ones; and the gravitational pull of the whole Milky Way galaxy lures stars away too. As a result, open star clusters rarely reach their billionth birthday.
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The Hyades has survived longer than many of its peers. But astronomers first saw signs of trouble there in 2018, when teams in Germany and Austria independently used the European Space Agency’s Gaia space observatory to find numerous stars that had escaped the cluster. These departing stars form two long tails on opposite sides of the Hyades — the first ever seen near an open star cluster. Each stellar tail stretches hundreds of light-years and dwarfs the cluster itself, which is about 65 light-years across.
In the new work, posted July 6 at arXiv.org, Oh and Cambridge colleague N. Wyn Evans analyzed how the cluster has lost stars over its life. It was born with about 1,200 solar masses but now has only 300 solar masses left. In fact, the two tails of escapees possess more stars than does the cluster. And the more stars the cluster loses, the less gravity it has to hold on to its remaining members, which leads to the escape of additional stars, exacerbating the cluster’s predicament.
Siegfried Röser, an astronomer at Heidelberg University in Germany who led one of the two teams that discovered the cluster’s tails, agrees that the Hyades is in its sunset years. But he worries that it’s too early to pin a precise date on the funeral. “That seems to be a little bit risky to say,” Röser says. Running a computer simulation with the stars’ masses, positions and velocities should better show what will happen in the future, he says.
The main culprit behind the cluster’s coming demise, Oh says, is the Milky Way. Just as the moon causes tides on Earth, lifting the seas on both the side facing the moon and the side facing away, so the galaxy exerts tides on the Hyades: The Milky Way pulls stars out of the side of the cluster that faces the galactic center as well as the cluster’s far side.
Even millions of years after the cluster disintegrates, its stars will continue to drift through space with similar positions and velocities, like parachutists jumping out of the same airplane. “It’s still probably going to be detectable as a coherent structure in position-velocity space,” Oh says, but the stars will be so spread out from one another that they will no longer constitute a star cluster. More
By Michael Marshall
The distribution of slavery in southern US states in 1860
Niday Picture Library / Alamy
A study of the DNA of people in the Americas with African heritage has revealed overlooked details about the transatlantic slave trade.
“This gives some clarity and some sense of individual history,” says historian Linda Heywood of Boston University in Massachusetts, who wasn’t involved in the research. DNA evidence means African Americans can pinpoint where their ancestors were abducted from and reclaim aspects of their heritage that were hidden by the slave trade, she says. “It broadens the way in which identity and personal history can be thought about.”
An estimated 12.5 million people were taken from Africa to the Americas between the 1500s and 1800s, according to historical texts like shipping documents and records of people being sold.
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To fill out the picture, Steven Micheletti of consumer genetics firm 23andMe in Sunnyvale, California, and his colleagues looked at DNA from 50,281 people, including 27,422 people from across the Americas with a minimum of 5 per cent African ancestry, 20,942 Europeans and 1917 Africans. This allowed them to identify stretches of DNA that are unique to people from particular regions of Africa.
The data came from 23andMe customers, along with public genome databases. Studies like this are becoming possible because African people, who were previously under-represented in genome databases, are now being asked to take part in research, says Joanna Mountain, also of 23andMe. Nevertheless, gaps remain. “I’m hoping we get some data from Mozambique sometime soon. It was involved in the slave trade, but we didn’t have enough data to include it in this study,” she says.
In line with historical records of where slaves were taken from, the African DNA in people in the Americas was most similar to that of people living in west African countries like Senegal, the Democratic Republic of the Congo and Angola.
However, most people in the Americas with African ancestry won’t have DNA from a single region of Africa. “Our results suggest the average African American would have connections to multiple regions,” says Micheletti. That is partly because slave traders disregarded ethnic identities, mixing people from different groups, and partly because African Americans moved around within the US. For instance, during the Great Migration of the 20th century African Americans moved from the segregated southern states of the US to northern states.
Because so many people were abducted as slaves, much of the genetic diversity in Africa was carried to the Americas, says Eduardo Tarazona-Santos at the Federal University of Minas Gerais in Belo Horizonte, Brazil. “But within the Americas, this diversity was more homogenised between populations.”
The analysis points to overlooked details of the slave trade. For instance, the team found less DNA from Senegal, Gambia and regions in other neighbouring countries than would be expected given the huge numbers of people taken from there. This may be because those slaves were often taken to rice plantations in the US, where the death rate was high due to malaria, says the team.
Meanwhile, many people in Central and South America and on many Caribbean islands today carry little African DNA – despite the fact that 70 per cent of slaves who survived the trip to the Americas were sent there.
This may reflect a form of racism once practised in Brazil, says Mountain, in which women of African descent were raped or forced to marry Europeans to promote “racial whitening”. In contrast, in the US, African Americans were often segregated from white people by law, and racial intermarriage was illegal or taboo.
The genetic data also confirms that female slaves have passed on much more of their DNA than male slaves – even though historical records show the majority of people taken from Africa were male. This is probably because female slaves were subjected to rape and sexual exploitation.
Journal reference: American Journal of Human Genetics, DOI: 10.1016/j.ajhg.2020.06.012
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Award-winning writer and campaigner Caroline Criado-Perez, speaks with New Scientist medical reporter Clare Wilson about how systematic gender biases are impacting women and men differently as the world copes with the coronavirus. For example, personal protective equipment is not only in short supply, its design – often based upon male body norms – is putting women at higher risk. Meanwhile, covid-19 affects men and women differently with men dying at a slightly higher rate, but many countries are not collecting sex-disaggregated data, making it difficult to understand the differences and mitigate some of the worst effects, she says. More
By Clare Wilson
A red fox raiding a bin on a residential street in London
Graham Racher / Alamy
We shouldn’t be surprised by how well foxes can survive by scavenging from our food leftovers – it is a behaviour that is tens of thousands of years old.
The ancestors of today’s foxes began living on humans’ food remains about 42,000 years ago, according to an analysis of animal bones found in Germany. “It’s the same as how they behave today in towns,” says Chris Baumann at the University of Tübingen in Germany.
Today, red foxes (Vulpes vulpes) and Arctic foxes (Vulpes lagopus) prey on small rodents in the wild as well as scavenging from the carcasses of animals, often those killed by large predators like bears and wolves. But the closer they live to towns and villages, the more their diet is made up of people’s food leftovers. “They’re very flexible,” says Baumann.
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He and his team analysed animal bones, including those of foxes, bears and wolves, found at sites in south-west Germany. The sites had been dated to three time periods: older than 42,000 years ago, when Neanderthals were the only humans living in the region, and two later periods when modern humans had moved in, lasting until 30,000 years ago.
By measuring the different isotopes of carbon and nitrogen in the bones, the team could work out what the animals had been eating. In the oldest period studied, foxes had eaten a mixture of animals, and these were likely to have been killed by bears, wolves and lions.
But after around 42,000 years ago, some of the foxes had switched to eating mainly reindeer. None of the other carnivores were mostly eating reindeer, so the foxes couldn’t have been scavenging from the kills of wolves, for instance.
While humans at the time ate a range of animals, including mammoths, “in cave sites, we find a lot of reindeer bones, because they are easy to transport as whole bodies to the caves”, says Baumann. “And if humans butchered them there, it would have produced food waste.”
Looking at the diet of foxes in other areas may become a new source of information about how ancient humans lived, says Baumann.
Journal reference: PLoS One, DOI: 10.1371/journal.pone.0235692
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A TV adaptation of Brave New World covers many of the same ideas as the book, but is stripped of relevance for the present day
Humans 22 July 2020
By Simon Ings
The Alphas of Brave New World run society while Epsilons toil in factories
Steve Schofield/Peacock
Brave New World
UCP/Amblin
Available on Sky One (UK) date TBC and Peacock (US) from 15 July
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THE 20th century produced two great British dystopias. The more famous one is 1984, George Orwell’s tale of a world unified into a handful of warring blocs run by dictators.
The other, Brave New World, was written in the space between world wars by the young satirist Aldous Huxley. It had started out as a send-up of H. G. Wells’s utopian works – novels such as Men Like Gods (1923), for instance. Then Huxley visited the US, and what he made of society there – brash, colourful, shallow and self-obsessed – set the engines of his imagination speeding.
The book is Huxley’s idea of what would happen if the 1930s were to run on forever. Embracing peace and order after the bloody chaos of the first world war, people have used technology to radically simplify their society. Humans are born in factories, designed to fit one of five predestined roles. Epsilons, plied with chemical treatments and deprived of oxygen before birth, perform menial functions. Alphas, meanwhile, run the world.
In 1984, everyone is expected to obey the system; in Brave New World, everyone has too much at stake in the system to want to break it. Consumption is pleasurable, addictive and a duty. Want is a thing of the past and abstinence isn’t an option. The family – that eternal thorn in the side of totalitarian states – has been discarded, and with it all intimacy and affection. In fact, no distinct human emotion has escaped this world’s smiley-faced onslaught of “soma” (a recreational drug), consumerism and pornography. There is no jealousy here, no rage, no sadness.
The cracks only show if you aspire to better things. Yearn to be more than you already are, and you won’t get very far. In creating a society without want, the Alphas have made a world without hope.
Huxley’s dystopia has now made it to the small screen. Or the broad strokes have, at least. In the series, Alden Ehrenreich – best known for taking up the mantle of Han Solo in Solo: A Star Wars story – plays John. Labelled a “savage” for living outside the walls of the World State, he encounters the Alpha Bernard Marx (Harry Lloyd) and Lenina Crowne (Jessica Brown Findlay), his Beta pal.
Bernard and Lenina are vacationing in Savage Lands, a theme park modelled a little too closely on Westworld in which people act out the supposedly sinful values of the old order for the entertainment of tourists. It is while they settle into their hotel room at the park that Lenina and Bernard suddenly realise they want to be alone together – a shockingly dirty idea in a world that has outlawed monogamy and marriage – and that “it could be our wedding night”.
“In Huxley’s book, characters were given a hard choice between freedom and happiness”
“We’re savages,” gasps Lenina, as it dawns on the two what they actually want. It is a scene so highly charged and sympathetically played that you only wish the rest of the show had lived up to it. The problem with Brave New World is that it is trying to be Huxley’s future in some scenes and trying to be our future in others. The two do not mix well.
Some of Huxley’s ideas about the future loom over us still. The potential eugenic applications of CRISPR gene editing keep many a medical ethicist awake at night. In other respects, however, Huxley’s dystopia has been superseded by new threats. Artificial intelligence is changing our relationship with expertise, so who needs human Alphas? At the other end of the social scale, Epsilons would struggle to find anything to do in today’s automated factories.
Squeezed by our technology into middle-ranking roles (in Huxley’s book, we would be Betas and Gammas), we aren’t nearly as homogenous and pliable as Huxley imagined we would be. Information technology has facilitated, rather than dampened, our innate tribalism. The difference between the haves and have-nots in our society is infocentric rather than genetic.
In Huxley’s book, the lands left for those deemed savages featured an unreconstructed humanity full of violence and sorrow. Characters were given a hard choice between freedom and happiness. None of that toughness makes it to the screen. At least, not yet.
The TV series is a weirdly weightless offering: a dystopia without lessons for the present day. It is as consumable and addictive as a capsule of soma, but no more nutritious.
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