Today in Science: Blocking the sun to cool the planet

Science meets inbox July 11, 2023: How the brain perceives silence, what can be done about "forever" chemicals and astronomers spot the oldest colliding galaxies. All that and more below! —Andrea Gawrylewski, Chief Newsletter Editor TOP STORIES The Sound of Silence Neuroscientists have long wondered if there's more to silence than meets the ear. Now they're finding that the brain might actively perceive silence in the same way it hears sound.  Why this is cool: While listening to loud ambient sounds, the brain processes instances of silence in the same way it processes instances of sound. "This suggests that our mind constructs similar auditory representations that might underpin our experience of silence," says Rui Zhe Goh, a Ph.D. candidate at Johns Hopkins, who led the new study. What the experts say: "Humans are distinctive in their ability to relate to things that are not immediately present to them," like holes or shadows, says Nico Orlandi, a philosopher of mind and of cognitive science at the University of California, Santa Cruz.  Forever Chemicals Nearly half of the nation's tap water is estimated to have one or more types of the chemicals known as per- and polyfluorinated alkyl substances, or PFAS, according to a new study released last week by the U.S. Geological Survey. Why this matters: PFAS appear in many consumer products (most things that are waterproof), as well as in materials like firefighting foam. They are considered indestructible, virtually nondegradable, accumulate in humans and the environment, and are suspected to cause asthma, cancer and changes in reproductive organs.  What can be done: A federal rule proposed at the end of 2022 would require companies to disclose whether their products contain "forever" chemicals. Researchers are also investigating ways to destroy these chemicals, including techniques that oxidize substances or that use high heat or high pressure.  IMAGE OF THE DAY Credit: NASA/ESA/CSA/Dan Coe (STScI)/Rebecca Larson (UT Austin)/Yu-Yang Hsiao (JHU). This image from the James Webb Space Telescope reveals ancient galaxies close to crashing into each other during the first 500 million years after the birth of the universe--by far the oldest event of this kind ever observed. The massive gravity of galaxy cluster MACS0647 (the bright center of this image) acts as a cosmic lens to bend and magnify light from the more distant MACS0647-JD system. In this case, the cluster lensed the JD system three times, each showing the merger of two galaxies. The three images are highlighted with white boxes and marked JD1, JD2, and JD3. Read more about this incredible discovery here. TODAY'S NEWS • Wildfire smoke hurts orangutans' voices and their health. You can hear about the research in the latest episode of Science, Quickly. | 12 min listen • A new supercomputer is helping climate scientists determine whether injecting human-made, sun-blocking aerosols into the stratosphere could cool the planet. | 3 min read • AI could be used to hasten the development of new antibiotics to fight drug-resistant bacteria. | 6 min read • 60,000 people died during intense heat waves in Europe last summer, indicating that heat prevention plans aren't protecting vulnerable populations. | 3 min read More News EXPERT PERSPECTIVES • The U.S. is experiencing low unemployment and rising wages. Despite this, new research indicates that families still rely on government benefits to bridge gaps between costs and earnings, write Katherine S. Newman and Elisabeth S. Jacobs. Rising cost of food, products and health care keep people in a cycle of poverty, they say. Newman is the provost for the University of California system, and Jacobs is senior fellow at the Center on Labor, Human Services and Population. | 5 min read More Opinion If you're a music lover like me, the finding above that silence is processed by the brain in the same way that sound is won't be very surprising to you--after all, some of the most poignant moments in music are in the rests, pauses and empty spaces. But it IS surprising that music can be used to treat brain disorders and heal injury–read more in this fascinating article from a few years back. I hope you're enjoying Today in Science. Email me anytime and let me know how to improve this newsletter: 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