Today in Science: Walking backward has health benefits

Science meets inbox April 2, 2024: The resiliency of old growth forests and are giant bubbles on Betelgeuse tricking us? Plus, walking backward may improve your health. —Andrea Gawrylewski, Chief Newsletter Editor TOP STORIES Old Growth Power In 2021 a Trump-era rule went into effect allowing logging of old-growth forests in six national forests. Last September, Senators Joe Manchin of West Virginia and John Barrasso of Wyoming introduced bipartisan legislation to "reduce catastrophic wildfire risk and improve forest health," largely through aggressive forest cutting. The vast majority of the country's old-growth forests have already been clear-cut, yet the U.S. Forest Service is pushing ahead with plans to clear tens of thousands of old growth woods.  Why this matters: Old-growth forests house diverse and rare ecosystems and threatened plant and animal species. They store 35 to 75 percent more carbon than logged stands. They cool the surrounding air. Most forests are not only naturally fire resilient (contradicting the political justification for their destruction), but many thrive from intermittent fires. Point of controversy: The Yaak River watershed covers 390,000 acres in the U.S. and includes spans of old-growth forest. The controversial Black Ram project proposed by the U.S. Forest Service would log parts of the Yaak, including a 192-acre parcel known as Unit 72, where some trees are 600 years old. "They say they'll log this old-growth forest—this wet, green rainforest—to create fire resilience," says Rick Bass, an author and forest activist, "but these trees are already fire-resilient. This larch, for example, is not only meant to survive fire; it's meant to prosper from it. Credit: Dolly Holmes Spin Illusion For decades, astronomical studies have found that the star Betelgeuse (the brownish star on the shoulder of the constellation Orion) is spinning 100 times faster than a star of that size should be. Now, a simulation from an international team of astrophysicists suggests that this anomalously high spin is an illusion, a case of observers being tricked by giant bubbles of plasma frothing up from the red supergiant's surface. Why this is cool: Betelgeuse is enormous, somewhere between 700 and 800 times the size of our sun. Each individual bubble of hot plasma (more technically called a "convective cell") boiling off its surface has a diameter about the size of Earth's orbit around our sun, some growing even larger. Regularly erupting and subsiding bubbles on one side of the star's visible disk and then the other gives the impression of a rapidly rotating star.  What the experts say: "I don't think [the new simulation] takes all the arguments into account completely," says Pierre Kervella, an astronomer at the Paris Observatory, referring to three previous independent observations of Betelgeuse by the Hubble Telescope and the Atacama Large Millimeter/submillimeter Array. "Who knows?" he adds. "It's a tortured star." An excerpt from a 3D simulation of the boiling, bubbling surface of the red supergiant star Betelgeuse. Credit: "Is Betelgeuse Really Rotating? Synthetic ALMA Observations of Large-Scale Convection in 3D Simulations of Red Supergiants," by Jing-Ze Ma et al., in Astrophysical Journal Letters, Vol. 962, No. 2, Article No. L36; February 20, 2024 (CC BY 4.0) TODAY'S NEWS • Walking backward can engage and strengthen muscles and take pressure off joints. | 3 min read • Medical chatbots are more likely to produce incorrect responses to health care queries in Mandarin Chinese, Hindi and Spanish compared with English. | 5 min read • U.S. landfills emit 40 percent more methane than we thought. | 4 min read • Are your solar eclipse glasses fake? Here's how to check. | 5 min read More News EXPERT PERSPECTIVES • Decades of research show that—when done strategically and fairly—policing reduces crime. But the context matters, write the authors of a recent study on policing in Denver, Co. Some cities experience different impacts from reduced policing and different policing strategies. "Getting policing right means striking a balance between the excesses of police activity and a lack of safety that simultaneously and disproportionately burden disadvantaged groups in our country," they say. | 3 min read More Opinion Some environmental economists have attempted to put a monetary value on the services that nature provides to us (one 2014 estimate landed on $140 trillion). It's handy to have such numbers in our pocket and I would guess we've even undervalued our natural ecosystems. But if you've ever sat beneath the branches of a 1,000-year-old tree, you might come away thinking that no pile of cash could ever compensate for the loss of these ancient lifeforms.  Reach out any time and let me know your favorite old forests (or new ones!): newsletters@sciam.com. Until tomorrow. —Andrea Gawrylewski, Chief Newsletter Editor Subscribe to this and all of our newsletters here. Scientific American One New York Plaza, New York, NY, 10004   Support our mission, subscribe to Scientific American here   Unsubscribe Email Preferences