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Neutrophils (artificially coloured) can extrude a sludgy substance in a ring around a puncture wound. Credit: Steve Gschmeissner/SPL
Immune cells in the skin create their own ‘bandages’ to prevent harmful bacteria spreading from the site of an injury, a study in mice reveals. Researchers found that white blood cells called neutrophils form a ring of protein-rich ‘goo’ around areas where the skin has been breached to trap pathogens. Neutrophils are known as the first responders to sites of infection and injury, killing pathogens by ingesting them or releasing toxins. This study reveals that after the initial attack, a second wave of neutrophils is deployed to form the sticky barrier.
Fresh data have backed up the discovery that dark energy — the mysterious force that makes galaxies accelerate away from each other — has weakened over billions of years. Until last year, all findings were consistent with dark energy being a ‘cosmological constant’, meaning that the Universe should continue to expand at an increasingly fast rate. The new findings show that the amount of dark energy per cubic metre of space is now around 10% lower than it was 4.5 billion years ago, which means that cosmic expansion is now accelerating less.
Researchers have broken the record for quantum communication by sending an encryption key nearly 13,000 kilometres from China to South Africa via a ‘microsatellite’. The fridge-sized satellite sent pulses of laser light from a rooftop in Beijing to another at Stellenbosch University. The pulses formed a quantum key used to encrypt two images — one of China’s Great Wall and one showing part of Stellenbosch’s campus. The feat, known as quantum key distribution, is a step towards being able to beam ultra-secure messages through space between any two locations on Earth, however far apart.
Within 4 years, artificial intelligence (AI) systems could outpace human computer programmers on long tasks that take months, and which they’ve so far lagged on. Since 2019, the ‘task-completion time horizon’ — a metric devised to track how long programmers take to complete tasks that AI can complete with a 50% success rate — has doubled roughly every seven months. That suggests tasks that take humans about a month will be mastered by AIs with 50% reliability by 2029, or possibly sooner. That said, uncertainties about how AI will be used mean these kinds of extrapolations aren’t always useful, says management professor Joshua Gans.
Reference: arXiv preprint (not peer reviewed)
Features & opinion
Starlink satellites leave streaks in a 2019 image taken by a 4-metre telescope at the Cerro Tololo Inter-American Observatory in Chile. (Credit: CTIO/NOIRLab/NSF/AURA/DECam DELVE Survey)
In the past five years alone, around 9,000 satellites were launched into Earth orbit, taking the total from just over 2,000 to 11,000. More than 7,000 of those newcomers belong to the Starlink system run by entrepreneur Elon Musk’s company, SpaceX. The spacecraft play a crucial role in connecting people around the world, but their soaring numbers are giving astronomers a headache by creating streaks in images and interfering with observations. The focus now is damage control. Astronomers are working with satellite companies to build a centralized tracking system, develop technologies that can de-streak their images and re-direct signals that can overwhelm radio telescopes.
A court case in Australia about the fate of pleistocene human remains taken from the dry bed of Lake Mungo in the 1960s and 1970s is coming to a head. The remains nicknamed ‘Mungo Lady’ show evidence of one of the world’s oldest-known cremations, while ‘Mungo Man’ is among the earliest human skeletons ever found. The bones are remains of Aboriginal Australian people and — along with many more from the same area — have come to represent both the history of First Nations people and how science has sometimes disrespected their rights, by treating their ancestors as scientific material without permission. In 2022, the process began to rebury the remains — but there is disagreement, both among scientists and members of Aboriginal Australian communities, about whether that was the right decision.
Image of the week
This spinning globe was displayed on an LED with microscopic pixel sizes.Credit: Y. Lian et al./Nature
Physicists have created the tiniest light-emitting diode (LED) displays ever. The image above was shown on a monochromatic display with pixels less than 100 micrometres across, about the width of a human hair. If that wasn’t small enough, the team made an even tinier LED. The pixels in this teensy display were just 90 nanometres wide — about the size of a virus, and too small to be resolved even by the most powerful optical microscopes. (Nature | 3 min read)
Today I’m catching up on sci-fi drama Severance. Fans of the series are left with a whole host of questions at the end of every episode — like what on Earth is going on? TV journalist Nic Juarez had another question on their mind: how much do employees of the shadowy Lumon company get paid for their “mysterious and important” activities? If you too were wondering, you’re in luck. Juarez has worked it out: approximately US$125,800 each year.
While I ponder whether I would let Nature put a chip in my brain to sever my ‘work’ and ‘home’ selves for that amount of money, why not give this newsletter a performance review at [email protected].
Thanks for reading,
Jacob Smith, associate editor, Nature Briefing
With contributions by Flora Graham
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