The Real Fusion Energy Breakthrough Is Still Decades Away

Last week, inside a gold-plated drum in a Northern California lab, a group of scientists briefly recreated the physics that power the sun. Their late-night experiment involved firing 192 lasers into the capsule, which contained a peppercorn-sized pellet filled with hydrogen atoms. Some of those atoms, which ordinarily repel, were smushed together and fused, a process that produces energy. By standards of Earth-bound fusion reactions, it was a lot of energy. For years, scientists have done this type of experiment only to see it fall short of the energy used to cook the fuel. This time, at long last, they exceeded it.

That feat, known as ignition, is a huge win for those who study fusion. Scientists have only had to gaze up at the stars to know that such a power source is possible—that combining two hydrogen atoms to produce one helium atom entails a loss of mass, and

NASA’s Orion Moon Capsule Is Back. What Happens Next?

After circling the moon for the past three weeks, NASA’s Orion capsule splashed down under parachute yesterday morning off the coast of Mexico’s Baja California near Guadalupe Island, marking an end to the Artemis program’s first major lunar mission. Orion was then scooped up by a recovery crew and sent to port in San Diego, carried in the well of the Navy ship USS Portland. With Artemis 1 in the books, NASA will scrutinize the capsule’s performance, making sure it is safe for future crewed trips to the moon, including a much-anticipated lunar landing in 2026.

“It’s a historic achievement because we are now going back into deep space with a new generation,” said NASA chief Bill Nelson following Orion’s splashdown. “This is a defining day. It is one that marks new technology, a whole new breed of astronaut, a vision for the future.”

During Sunday’s descent, the three

Your Brain Uses Calculus to Control Fast Movements

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

‘Solar Twins’ Reveal the Consistency of the Universe

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

The Extraordinary Shelf Life of the Deep Sea Sandwiches

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

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