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September 15, 2025—The hunt for Saturn's many moons, new findings about daylight saving time and why Mondays really are stressful. —Robin Lloyd, Contributing Editor | | NASA, ESA, John T. Clarke (Boston University), Zolt G. Levay (STScI) | | Saturn is now thought to boast a staggering 274 official moons, most of which are just a few kilometers wide. In just the past decade, astronomer Edward Ashton helped discover 192 of them, using data gathered by the Canada-France-Hawaii Telescope (CFHT), in Hawaii, reports Scientific American senior news reporter Meghan Bartels. To find the moons, Ashton relied on a "shifting and stacking" detection process, which starts by taking 44 images of the same piece of the sky over a three-hour time period. How it works: During that time interval, the moons move relative to the stars at a rate similar to that of Saturn. After stacking the images and then shifting them relative to one another at multiple different rates near that of Saturn, the astronomers then view the images like a flip-book to search for objects that start off slightly elongated and then combine into a dot before expanding again. Subsequent tracking confirms whether the candidate objects orbit the planet. Why this is cool: The same technique has been used to find moons of Neptune and Uranus. No one previously had tackled searching for Saturn's moons in this way because the expanse of sky around Saturn where moons could exist (have stable orbits) is much larger than the same expanse around the less massive Neptune and Uranus. | | The stress of Monday can extends well beyond the start of the typical work week, write medical sociologist Tarani Chandola and cognitive neuroscientist Benjamin Becker. Heightened activity in the body's stress-response system—specifically levels of the stress hormone cortisol—can persist for months among people, including retirees, who report feeling anxious on Monday, according to data analyzed by Chandola. Unchecked, high cortisol levels disrupt our system in ways that increase the risk of cardiovascular disease, diabetes, impaired immune function and depression. How it works: Levels of cortisol, which help maintain energy and mental focus at healthier levels, were 23 percent higher on average in hair samples collected from older people who reported feeling anxious on Mondays than among those who didn't. In some subjects, high cortisol persisted for two months. The cortisol finding was absent among people who reported anxiety on other days of the week. What the experts say: "For some people, Monday blues are not a personal minor inconvenience but a persistent stressor with long-term—perhaps lifelong—detrimental effects on physical and mental health," the authors write. Solutions could include good sleep hygiene, regular physical activity and meditation. | | | | |
Among the natural numbers below 100, there are 30 with a special property. Jovan has listed them in the table here. But Jovan made a mistake, and one of these numbers must be replaced. Which number must be inserted in place of the incorrect number? Click here for the answer.
| | Public debate about daylight saving time (not to mention whether to call it "daylight savings time") has waxed and waned for more than a century. I recall walking to school in the dark during the energy crisis in the 1970s. I was half-asleep on those walks and potential crime didn't occur to me. It's good to see a new study of the health implications of "changing the clocks," in the story above by Scientific American news intern Humberto Basilio. In 2018, a piece by science journalist and data-visualization designer Katie Peek showed a complex set of findings about whether daylight saving time is good or bad for health, safety, energy savings and personal safety. | | We always like to hear from you, any day of the week, any time of day. Feel free to reach out with feedback, questions and thoughts about daylight saving time: newsletters@sciam.com. —Robin Lloyd, Contributing Editor
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