February 25, 2025: Physicists want to redefine the second. Plus, AI that gazes into goats' faces and extreme weather swings. —Andrea Gawrylewski, Chief Newsletter Editor | | | Ice collects along the shore of Lake Michigan as temperatures were in the single-digits for most of the day on February 17, 2025, in Chicago, Ill. Scott Olson/Getty Images | | | • Widening highways doesn't fix traffic. This is what can (and it costs a lot less). | 5 min read | | | Nitin Prabhudesai/Getty Images | Scientists videotaped 40 goats of various breeds and ages with different medical conditions at a veterinary hospital, generating more than 5,000 fixed frames. Using a behavioral pain scale, clinical history and physical exams, they classified each goat as in pain or not. They trained an algorithm on the data and then tested how well the AI could determine whether an animal was in pain or not, based on a new set of images. The AI achieved 80 percent accuracy at detecting goats in pain. (And before you flood my inbox, yes, I know that ewes are sheep, not goats. But they're closely related.)
Why this matters: Detecting suffering in animals is notoriously difficult and usually comes down to analyzing photos or videos by hand for specific cues—a raised lip, a flared nostril—and creating pain scales tailored to individual species. But those interpretations are subject to human biases, and not necessarily substantiated displays of pain. AI-powered tools could someday help veterinarians make quicker and more accurate diagnoses or alert farmers to early stages of livestock distress.
What the experts say: When detection is automated, "the computer just picks up the patterns," says University of Florida veterinary anesthesiologist Ludovica Chiavaccini. It "essentially builds 30 years of clinical experience in 30 minutes." | | | Many scientists believe it is time for a new definition of the second. The current second is set by the number of waves of microwave energy absorbed and emitted by cesium atoms (called the resonance frequency). But newer instruments, called optical clocks, use different atoms, like strontium or ytterbium, that release optical light at much higher frequencies than cesium. This yields 50,000 times more "ticks" than a cesium clock can measure in a second, and thus gives a more precise reference for one's definition.
How it works: A cesium clock shines light on atoms of cesium to excite them. As the atoms come down from their excited state, they emit photons, producing light with a metronomic frequency that the instrument records. The clock counts the number of wave crests of light that pass from the atoms in a given time, and scientists use that rate to time an exact second. An official second is 9,192,631,770 cycles of cesium's resonance frequency.
What the experts say: Some scientists wonder how necessary a new second really is. Current cesium clocks are accurate enough for most practical purposes like synchronizing GPS satellites. Plus, novel atomic methods must be sifted through to select a new standard. Regardless, "it's just a matter of basic principle," says Elizabeth Donley, chief of the time and frequency division at the National Institute of Standards and Technology. "You want to allow for the best measurements you can possibly make." | | | If you're enjoying all the science we cover in this newsletter, dive deeper with a subscription to Scientific American. You'll have access to all our articles and will be supporting crucial science journalism. | | | • The human brain sees astounding patterns in places like sports (some players seem to go through "hot streaks") or in hospital births (nurses often report strings of all girls or all boys being born). We often attribute these surprising observations to luck or other forces, but the truth is, with big enough data sets, wild things are bound to happen naturally, writes David G. Myers, a social psychologist at Hope College. "We can realize the realities of randomness and yet find pleasure in life's weird streaks and coincidences," he says. | 5 min read | | | Human brains are constantly bombarded with information. Natural filters help us make sense out of noise and carry out one task at a time—a lucky phenomenon for getting anything done. But we also have a tendency to process information with bias (perhaps a bi-product from making quick sense from a deluge of incoming data). Of course, science shows us ways for avoiding these common pitfalls (and seeing false "patterns" in ordinary events), but they require diligent self-checking and an open mind. Scientific thinking is something anyone can do, no matter their profession! | How do you keep an open mind? Let me know by emailing newsletters@sciam.com. I'd love to share your ideas with other readers. | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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