Today in Science: Superheated gold overturns 40 years of physics

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July 24, 2025—COVID aged all our brains, why it's so hard to wake up, and a math problem involving convex shapes is finally solved.   —Andrea Gawrylewski, Chief Newsletter Editor TODAY'S NEWS Greg Stewart/SLAC National Accelerator Laboratory Scientists used a laser to heat gold to more than 33,000 degrees F without melting the material. The feat was completely unexpected and has overturned 40 years of accepted physics about the temperature limits of solid materials. | 3 min read Waking up is a process of ordered activation in the brain from front to back. | 3 min read The COVID pandemic aged everyone's brain—even people who didn't get infected—according to a new study of 1,000 people. | 3 min read The largest trial yet of a four-day work week, involving 141 companies, found the schedule makes employees happier and feel just as productive. | 3 min read More News TOP STORIES   Slicing Problem Solved In the mid-1980's, mathematician Jean Bourgain posed a question: Does every convex shape—a shape curved outwards with no indentations or curves inward—always have a "slice" whose cross-section is bigger than some fixed value? Simply put, yes, a group of mathematicians has shown. For example, a three-dimensional convex object like a watermelon or pear, will always have a sliced cross section bigger than a fixed value. How they did it: At the end of 2024, a group of physicists used a model to measure how quickly heat diffused out of a convex shape. Since the heat behaved according to physical laws, the rate that it dissipated was known, and the scientists could decipher hidden geometric structures within the shape. This rate limit of dissipation was the missing link. Building on these findings, the mathematicians in the new study were able to solve Bourgain's problem.  Why this matters: Bourgain's question seems easy in the physical world's two or three dimensions, but it gets more complicated as you start adding more dimensions. The findings help demystify the labyrinthine geometry of high-dimensional shapes, something especially important for mathematicians and other scientists who regularly work with such complicated shapes, such as statisticians, machine-learning researchers and computer scientists. —Andrea Tamayo, newsletter writer

WATCH THIS Scientific American/Getty/SxS Scientific American visited the LIGO Lab at the Massachusetts Institute of Technology and sat down with Matt Evans, MIT's MathWorks professor of physics. Components in the MIT lab are tested and shipped off to gravitational wave observatories around the country. Right now LIGO detectors are gathering data on binary systems, he says, "And these can be pairs of black holes, pairs of neutron stars or a mix-and-match black hole-neutron star system." Watch the full video here.  ​ Get full access to every article in Today in Science by subscribing to Scientific American. Thank you for supporting science journalism!

SCIENTISTS AT WORK Ulet Ifansasti  Plant scientist Johan Sukweenadhi is working to turbocharge the growth of the medicinal plant ginseng (Panax ginseng). "We use a method known as hairy-root culture, which uses the soil bacterium Rhizobium rhizogenes to infect plant roots, causing them to grow abnormally fast in artificial media without producing stems or leaves," he says. "Although the root itself is a valuable crop, our ultimate goal is to discover medicines." Nature | 3 min read   Content courtesy of Nature Briefing Numerous studies of four-day work weeks have found that salaried employees feel less burnout and stress with the extra day off, and productivity doesn't slip. In fact, in the recent study featured above, about 90 percent of companies who experimented with a four-day week kept it going after the trial period ended. Are you in favor of a four-day work week?  Let me know and send any other ideas or suggestions to: newsletters@sciam.com.    —Andrea Gawrylewski, Chief Newsletter Editor

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