Philippa Kaur

By Donna Lu
We finally know where most of Stonehenge’s sarsen stones came from
Andre Pattenden (English Heritag

The origins of the giant boulders at Stonehenge have long been a mystery – but now we have uncovered where they came from.
David Nash at the University of Brighton in the UK and his colleagues have identified the source of 50 of the 52 large boulders, known as sarsens, that make up the monument’s iconic stone circle.
By analysing the stones’ chemical composition, the team has traced their origins to 25 kilometres away from the monument, in the West Woods in Wiltshire.

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The sarsens comprise Stonehenge’s outer circle as well as a horseshoe-shaped inner ring. Many are in trilithons: two vertical stones topped with a horizontal lintel.
Stonehenge also contains smaller rocks, known as bluestones, near its centre, the origins of which have previously been traced to Wales.
The researchers analysed the chemistry of the sarsens via a technique called portable X-ray fluorescence spectrometry, essentially a handheld X-ray gun. With this, they took five readings at different positions for each stone.

This revealed that 50 sarsens shared a common chemistry, containing more than 99 per cent silica, with trace elements including aluminium, calcium and iron.
“Two, much to our surprise, were different to that main cluster, but also different to each other,” says Nash. This suggests they have two separate origins.

Next, the researchers analysed a fragment of stone, taken from a collapsed sarsen when it was re-erected in 1958, to obtain a geochemical breakdown of the rock. They used this to sample areas of similar stone across southern Britain.
The site in the West Woods, one of six the team sampled in the Marlborough Downs, turned up with a match. “We didn’t expect we would ever find the original source area,” says Nash.
Identifying the origins of the sarsens opens up the possibility of future archaeological research into the routes they may have been transported to Stonehenge, says Nash.
The origins of the other two sarsens have yet to be identified.
Journal reference: Science Advances, DOI: 10.1126/sciadv.abc0133
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We know that women live longer and are less susceptible to certain diseases than men. That may be down to the benefits of having two X chromosomes

Humans 29 July 2020
By Sharon Moalem

Rocio Montoya

WOMEN generally outlive men and are less susceptible to certain illnesses – including covid-19, it now appears. Why health outcomes are so drastically different between the sexes is unclear. But Sharon Moalem, a doctor and genetic researcher based in New York, thinks he has the answer. It isn’t because women tend to go to the doctor more or have healthier habits, he says. Instead, it’s because they are typically better equipped, genetically speaking.
In humans, sex is largely determined by chromosomes, the bundles of tightly coiled DNA that carry our genes. The cells of most women possess two X chromosomes while most men have one X and one Y. So that women’s cells don’t have to carry two versions of each gene on the X chromosome, one from each X, one of the Xs is mainly switched off. It appears that which one stays active in which cells is chosen seemingly at random some time during the first few weeks of pregnancy. The result is that half a women’s cells generally use the X chromosome she inherited from her mother, while the other half use the one from her father.
It has long been known that if one X has a harmful mutation, cells that use the other X can compensate. That’s why, for instance, women are less likely to be colour-blind; a gene important for eye function resides on the X chromosome. Yet Moalem argues that the benefits are far more significant than this alone. He makes the case that even if there is no obviously harmful mutation, women tend to be at an advantage by having bodies … More

A social media weather report that predicts outbreaks of propaganda is on its way. It can’t arrive soon enough, says Annalee Newitz

Technology | Comment 29 July 2020
By Annalee Newitz

Will Heath/NBCU Photo Bank/NBC

A FEW weeks ago, I noticed that a foul and offensive hashtag was trending on Twitter. Like a horror movie character who goes into the basement after hearing monster noises, I clicked on it.
Every post on the hashtag was like a parody of a political debate, with each side making the same screaming accusations. It was almost as if these people had learned to argue from bad algorithms.
That is when it hit me. Maybe these angry tweets were generated by algorithms. Or by operatives at a place like the Internet Research Agency … More

Alice Winocour’s new film Proxima shows the difficulties of balancing family life with a career as an astronaut, finds Simon Ings

Humans 29 July 2020
By Simon Ings
Astronaut Sarah Loreau (Eva Green) prepares to leave Earth in Proxima
Dharamsala & Darius films

Proxima
Alice Winocour

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In UK cinemas from 31 July
THE year before Apollo 11’s successful mission to the moon, Robert Altman directed James Caan and Robert Duvall in Countdown. The 1968 film stuck to the technology of its day, pumping up the drama with a somewhat outlandish mission plan: astronaut Lee Stegler and his shelter pod are sent to the moon’s surface on separate flights and Stegler must find the shelter once he lands if he is to survive.
The film played host to characters you might conceivably bump into at the supermarket: the astronauts, engineers and bureaucrats have families and everyday troubles not so very different from your own.
Proxima is Countdown for the 21st century. Sarah Loreau, an astronaut played brilliantly by Eva Green, is given a last-minute opportunity to join a Mars precursor mission to the International Space Station. Loreau’s training and preparation are impressively captured on location at European Space Agency facilities in Cologne, Germany – with a cameo from French astronaut Thomas Pesquet – and in Star City, the complex outside Moscow that is home to the Yuri Gagarin Cosmonaut Training Center. She is ultimately headed to launch from Baikonur in Kazakhstan.
Comparing Proxima with Countdown shows how much both cinema and the space community have changed in the past half-century. There are archaeological traces of action-hero melodramatics in Proxima, but they are the least satisfying parts of the movie. Eva Green is a credible astronaut and a good mother, pushed to extremes on both fronts and painfully aware that she chose this course for herself. She can’t be all things to all people all of the time and, as she learns, there is no such thing as perfect.

Because Proxima is arriving late – its launch was delayed by the covid-19 lockdown – advances in space technology have already somewhat gazzumped Georges Lechaptois’s metliculous location cinematography. I came to the film still reeling from watching the Crew Dragon capsule Endeavour lift off from Kennedy Space Center on 20 May.
That crewed launch was the first of its kind from US soil since NASA’s space shuttle was retired in 2011 and looked, from the comfort of my sofa, about as eventful as a ride in an airport shuttle bus. So it was hard to take seriously those moments in Proxima when taking off from our planet’s surface is made the occasion for an existential crisis. “You’re leaving Earth!” exclaims family psychologist Wendy (Sandra Hüller) at one point, thoroughly earning the look of contempt that Loreau shoots at her.
Proxima‘s end credits include endearing shots of real-life female astronauts with their very young children – which does raise a bit of a problem. The plot largely focuses on the impact of bringing your child to work when you spend half your day in a spacesuit at the bottom of a swimming pool. “Cut the cord!” cries the absurdly chauvinistic NASA astronaut Mike Shannon (Matt Dillon) when Loreau has to go chasing after her young daughter.
Yet here is photographic evidence that suggests Loreau’s real-life counterparts – Yelena Kondakova, Ellen Ochoa, Cady Coleman and Naoko Yamazaki – managed perfectly well on multiple missions without all of Proxima‘s turmoil. Wouldn’t we have been better off seeing the realities they faced rather than watching Loreau, in the film’s final moments, break Baikonur’s safety protocols in order to steal a feel-good, audience-pandering mother-daughter moment?
For half a century, movies have struggled to keep up with the rapidly changing realities of the space sector. Proxima, though interesting and boasting a tremendous central performance from Green, proves to be no more relevant than its forebears.
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A group of troubling disorders including functional neurological disorders can lead to very real symptoms, but tests suggest nothing is wrong. Finding out why is shedding new light on the nature of consciousness itself. Jamie Lacelle suffers from a functional neurological disorder. This is her story. More

In his new book Novacene, James Lovelock says the creation of AlphaGo was the start of a new kingdom of life that will create and think for itself. He’s optimistic that this new kingdom of life will want to keep us around like we keep plants in gardens. In our interview at his house near Chesil Beach we discuss the future of Gaia, our new AI overlords and why Elon Musk’s Mars mission is crazy. More