May 28, 2024: What happens when a supernova hits Earth, the 2024 hurricane forecast, and an icy plunge could improve your health. —Andrea Gawrylewski, Chief Newsletter Editor | | | Swim With the Polar Bears | If you went swimming at the beach over the long weekend, perhaps you felt invigorated by chilly spring water temps. Cold-water bathers report pain relief from musculoskeletal injuries, and decreased symptoms of depression, as well as mood improvement. A recent survey of 1,114 female cold-water swimmers found that plunging into icy waters eased symptoms of menstruation and menopause.
What the experts say: The benefits of the practice are "quite difficult" to assess, says James B. Mercer, an emeritus physiologist at UiT the Arctic University of Norway. Most studies on the subject have been small, with generally healthy participants and widely varying water temperatures and salinity levels, so it's tough to tease out what is behind the perceived benefits. | | | Every few million years, a supernova goes off close enough to Earth to shower the planet with radioactive debris. Researchers found elevated amounts of the isotope iron 60 in sediments on the deep sea floor and in deep-sea bacteria. This isotope has only one source: the nuclear fire of an exploding star. By measuring its rate of decay, the scientists estimate that it was deposited by multiple supernovas around 2.5 million years ago, perhaps originating in the Scorpius-Centaurus association, a clump of stars about 390 to 470 light-years from Earth.
Why this is cool: "The amount of iron 60 in the sediments is actually quite small, very roughly 100,000 atoms per gram of material," writes astronomer and Scientific American columnist Phil Plait. "But the astonishing thing is that debris from exploding stars quadrillions of kilometers from us is there at all."
What the experts say: Researchers determined that a supernova would have to be less than about 160 light-years from Earth to inflict any significant damage, like high energy gamma rays destroying our ozone layer, or a blast of radiation that knocks out our power grid. For now, no such close explosion is likely to happen, Plait writes. | | | Adult plainfin midshipman (Porichthys notatus) in a Puget Sound tide pool. Cavan Images/Alamy Stock Photo | | | • Autonomous and AI-enabled systems (like next-gen military aircraft) increasingly rely on optical and radio frequency sensors and significant computer power. But these systems are vulnerable to directed-energy weapons (DEWs) that can disrupt or damage the sensors and electronics that such autonomous systems depend on, writes David C. Stoudt, a senior executive advisor and fellow for directed energy at Booz Allen Hamilton. "The perceived lack of implementation of hardening techniques against microwaves and lasers may drive accelerated investment in worldwide DEWs by all stakeholders (governments and bad actors alike)," he says. | 5 min read | | | For the freeze-o-philes out there (or aspiring cold plungers), some private facilities now offer cryotherapy, where the body is gradually exposed to colder and colder air, which is chilled by liquid nitrogen. It's slightly less "shocking" than jumping in an ice bath or frigid ocean, but intense nonetheless. Remember that research on cold exposure is limited, so proceed with caution! | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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