A daily read for all who love science, discovery, and insight ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
September 23, 2025—Tylenol is safe and effective, though scientists don't know precisely how it works. Plus, the moon is rusting and where Internet slang comes from. —Andrea Gawrylewski, Chief Newsletter Editor | | Ilgın Akgün (left), Saransh Singh (center), Walter Fertig (right) | | - Today we announced the winners of the #SciAmInTheWild photography contest! And check out the shortlist of finalists in the link above—so many creative and inspiring entries. | 4 min read
- Tiny fossils discovered in northern Alaska hint that birds began making a mind-blowing journey to the Arctic to breed at least since the time of the dinosaurs. | 14 min read
- In 2023, powerful vaccines and treatments against the respiratory virus RSV became widely available. Already they've led to a "stunning drop" in infant hospitalizations. | 9 min read
- The moon is rusting as oxygen particles blown all the way from Earth turn lunar minerals into hematite. | 3 min read
- Where do slang terms like "fam" or "yeet" or "brain rot" come from? We sat down with linguist Adam Aleksic on how social media is transforming language. | 27 min listen
| | Yesterday, President Trump and Health and Human Services Secretary RFK, Jr., said that acetaminophen (known commonly by the brand name Tylenol) caused autism in kids whose moms had taken the drug while pregnant. Those statements go against the most conclusive scientific evidence to date (for a detailed breakdown of the safety of Tylenol during pregnancy and autism, I recommend this excellent explainer). Why this matters: Some 52 million consumers use a product containing acetaminophen every week in the U.S, according to one health care trade association. The drug has been shown to be safe and effective and is the only over-the-counter pain medicine recommended by doctors during pregnancy. Controlling a fever and infections during pregnancy is vital to preventing harm to the fetus—uncontrolled fevers during pregnancy increase the risk of autism. Why this is interesting: Despite its widespread use, the precise mechanism of action of the drug—the molecular explanation for how it blocks pain and fever— is still somewhat of a mystery. One hypothesis is that acetaminophen prevents the formation of prostaglandins, substances that can heighten pain and drive inflammation and fever. The second hypothesis is that the drug stops the production of endogenous cannabinoids, chemicals involved in the pain response. What the experts say: "Pain pathways are very complicated," says Alex Straiker, a neuropharmacologist at Indiana University's Gill Institute for Neuroscience. "So acetaminophen is likely to have multiple targets." | | Magnet for CERN's LHCb particle detector. CERN/Science Source | | Matter and antimatter are mirror opposites. Besides their electric charge, they are nearly identical. However, sometimes, they behave differently from each other. These slight distinctions are known in the field as a violation of conjugation-parity symmetry, or CP violation, and explain how some matter escaped destruction in the early universe. For the first time, scientists using the Large Hadron Collider near Geneva measured a CP violation in baryons, a class of particles made up of three quark types—an "up" quark, a "down" quark and a "beauty" quark. Baryons made up of these quark types decayed more often than baryons with the antimatter version of each of those particles. Why it's important: Physicists believe that when the universe was born there were equal amounts of matter and antimatter. However, the two destroyed each other, with CP violation leaving intact some matter in the wake of the battle. The remaining matter created everything around us—planets, people, stars. And it helps explain a fundamental question in physics—why do we have something rather than nothing? This new discovery inches physicists closer to answering why trace amounts of matter persisted. What the experts say: "This is a milestone in the search for CP violation," says Xueting Yang of Peking University, a member of the LHCb team that analyzed the data behind the measurement. "Because baryons are the building blocks of the everyday things around us, the first observation of CP violation in baryons opens a new window for us to search for hints of new physics." —Andrea Tamayo, Newsletter Writer
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- Can you unscramble this image of our cover from February 1959? The assembled illustration shows reactor fuel elements and the many intricate forms they may take to fine-tune a fission reaction.
**Question for readers: Some of you have requested I not include the finished image here so as to not give away the final puzzle. What do you prefer?** | | We received dozens of entries for our SciAm cover shot contest. It was delightful to see so many of our covers out in the wild and the creative ways that readers framed their shots. Enjoy scrolling through the contest winners and our other favorites. One of the oldest covers entered was the February 1908 cover, a reminder of how long Scientific American has been a staple of science journalism. | | Please send any ideas, comments or feedback on this newsletter to: newsletters@sciam.com. See you tomorrow! —Andrea Gawrylewski, Chief Newsletter Editor
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