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A mouse is running on a treadmill embedded in a virtual reality corridor. In its mind’s eye, it sees itself scurrying down a tunnel with a distinctive pattern of lights ahead. Through training, the mouse has learned that if it stops at the lights and holds that position for 1.5 seconds, it will receive a reward—a small drink of water. Then it can rush to another set of lights to receive another reward.

This setup is the basis for research published in July in Cell Reports by the neuroscientists Elie Adam, Taylor Johns and Mriganka Sur of the Massachusetts Institute of Technology. It explores a simple question: How does the brain—in mice, humans and other mammals—work quickly enough to stop us on a dime? The new work reveals that the brain is not wired to transmit a sharp “stop” command in the most direct or intuitive way. Instead, it

Sometimes we must look to the heavens to understand our own planet. In the 17th century, Johannes Kepler’s insight that planets move in elliptical orbits around the sun led to a deeper understanding of gravity, the force that determines Earth’s tides. In the 19th century, scientists studied the color of sunlight, whose distinctive properties helped reveal the quantum structure of the atoms that make up the star—and all matter around us. In 2017, the detection of gravitational waves showed that much of the gold, platinum, and other heavy elements on our planet are forged in the collisions of neutron stars. 

Michael Murphy studies stars in this tradition. An astrophysicist at Swinburne University of Technology in Australia, Murphy analyzes the color of the light emitted by stars similar to the sun in temperature, size, and elemental content—”solar twins,” as they are called. He wants to know what their properties reveal about

In the late 1960s, a submersible named Alvin suffered a mishap off the coast of Martha’s Vineyard. The bulbous white vessel, holding a crew of three, was being lowered for a dive when a cable snapped. Suddenly, Alvin was sinking. The scientists clambered out, shocked and a little bruised, as the vessel plunged, hatch ajar, eventually settling in the seabed some 4,500 feet below. Alvin was in a slightly embarrassing situation. Though the sub was only a few years old, it had an eclectic résumé that included, in 1966, helping to recover a 70-kiloton hydrogen bomb that was dropped when two military planes collided over the Spanish coast. Now it was the one that needed saving. 

Ten months later, Alvin was pulled from the depths—a blip in the life of a vessel that makes dives to this day (though a steady replacement of parts means none of the original sub

The skin is the largest organ in our body, and also the most complex. Peer at it under a microscope and you’ll see thousands of nerve endings that keep the brain connected to the outside world and allow us to feel touch, pressure, and pain. But when Zhenan Bao looks at it, she sees something else.

For Bao, a chemical engineer focused on making polymers, the skin is not only a sensory organ, but also a material. One that, in her words, is flexible, but also stretchable, self-healing, and biodegradable. Bao works in the emerging field of electronic skin and has made it her mission to recreate the many functions of human skin for use in prosthetics and robotics. For people who wear artificial limbs, a sense of touch would immeasurably improve their quality of life—enabling them to distinguish soft from hard and to notice the dangerously sharp or the

At the end of 2021, a group of night poachers in a Mozambique national park—using torchlight to blind antelopes—were suddenly the ones left stunned in the dark. The poachers, local opportunists looking for bushmeat in the area’s savannahs, forests, and wetlands, are often able to kill hundreds of animals in one hunt with near impunity, using dogs to track and finish off their prey. They move with confidence because they can hear the noisy petrol motorbikes of the overstretched rangers from more than a mile away, enabling them not only to escape, but also to know where the park’s guardians are and hunt around them—easy enough to do in the thousands of square miles of terrain.

Not this time. A team of rangers silently moved in on their off-road ebikes, halting the hunt immediately. The nearly silent motor of the ebike—a factor that can make them an accident risk in