How extreme heat steals hours of sleep

Plus, what to know about postpartum depression ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏  ͏ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­ ­

July 31, 2026—A glimpse of underwater volcanism, a near-collision of two AI results and the start of a decade-long “movie" of the sky.   —Robin Lloyd, Contributing Editor TODAY'S NEWS This map shows a representative week of observations by the Vera C. Rubin Observatory for its decade-spanning Legacy Survey of Space and Time. Each color-coded tile represents one of six filters used for an individual exposure. NSF–DOE Vera C. Rubin Observatory/NOIRLab/SLAC/AURA Using the new Rubin Observatory, astronomers are capturing the start of a decade-long “movie” of the sky that is expected to be revolutionary. | 5 min read Pumice, or “frothy rock,” floating in seawater near Papua New Guinea signaled a chance for a rare glimpse into underwater volcanism. | 3 min read Two research efforts used the same AI model to solve the same “unclonable encryption” problem via different means. Their results were published 3 hours and 18 minutes apart, raising questions about what counts as independent discovery. | 4 min read Postpartum psychosis is an understudied yet treatable disorder. The condition is gaining attention with the trial of a mother who allegedly murdered her young children during a psychotic episode. | 2 min read The devastating, atomic bombing of Hiroshima in 1945 created a bizarre new metallic alloy. Scientists just discovered it. | 2 min read  Lakes of liquid methane on Titan, Saturn’s largest moon, could someday offer exhilarating—and terrifying—opportunities for otherworldly surfing. | 5 min read “Protein maxxing” is all the rage, but a research summary of more than 350 previous studies found widespread evidence that eating less protein could help you live longer. | 5 min read TOP STORIES Sleep Lost to Heat Heat waves can cause kidney problems, heatstroke and even death. When temperatures remain high overnight, the extreme heat also takes a toll on our sleep, report Scientific American's Jackie Flynn Mogensen and Sanidhya Sharma. Between 2020 and 2025, high overnight temperatures cost the average person across the world an estimated 56 hours of sleep per year, according to a recent analysis from the nonprofit Climate Central. Climate change accounts for about six hours per year of that loss. ​ Why this matters: Sleep loss puts us at risk for poor mental health and higher rates of heart disease and obesity. It can even increase the occurrence of intrusive thoughts. ​ What the experts say: “There are subtle and small ways that climate change is eroding our quality of life. It may not feel like a lot now, but if you look at the trajectory over time, it’s clearly increasing. And if we continue to warm, it's just going to get greater,” says Kristina Dahl, Climate Central’s vice president for science. ​ ​ Sanidhya Sharma; Source: Climate Change Is Costing People Sleep. Climate Central, July 15, 2026 (data)

BROUGHT TO YOU BY SCIENTIFIC AMERICAN Join the SciAm Summer Reading Challenge! Summer's halfway over! But it's not too late to join our summer reading challenge. Fill in your Scientific American Summer Reading bingo card by exploring everything from eco-horrors to STEMinist romances to movie adaptations. After completing a square on the bingo card, tag us on social media or email contests@sciam.com for a chance to win one of 40 prize packages. Learn More

SCIENCE QUIZ How well did you read Scientific American this week? Test your knowledge with this week's science quiz. And don't stop there, we've got tons of games to keep you occupied for hours: Ken Ken Sudoku Spellements Crosswords Math puzzles RECOMMENDED READS Every Friday in summer we're recommending a great, freshly-published science read. Tell us what you're reading, fill in your bingo card and happy reading! Coding Kids: Big Tech's Battle to Remake Public Schools By Natasha Singer. Norton, September 8, 2026. Computer coding has taken the education world by storm, and the rise of artificial intelligence has amplified the craze. Tech industry giants like Google and Apple are pouring money into new coding curriculum—to their own benefit, and at the expense of students’ actual learning, as author and technology reporter Natasha Singer details in her new book. Singer gives a fascinating account of Big Tech’s outsized influence on how programming and AI are taught in schools: coding, once presented as a tool students can use as widely as reading or arithmetic, has been supplanted by a PR campaign for tech corporations disguised as “learning.” This is vital reading for anyone invested in the American education system. —Jennifer Hackett, Copy Editor MOST POPULAR STORIES OF THE WEEK How a 99-year-old mathematician unraveled a century-old braid mystery | 4 min read Hundreds of never-before-seen ancient ‘earthworks’ discovered in the Amazon | 3 min read Has NASA already found life on Mars? | 12 min read These days, dining out or "ordering in" can involve struggling to navigate an eatery’s web-based or mobile app menu. If you occasionally wish you could put your hands on a paper menu, you might enjoy reading this history of menus interactive, recently published by The Pudding. Scientific American also covered food history in our excellent "Science of Food" special edition​, including a piece on “the amazing multimillion-year history of processed food." Reach out any time to newsletters@sciam.com with your comments or questions. We read every email and respond to many. Hope you have a great weekend! —Robin Lloyd, Contributing Editor

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Week in Science: Hiroshima bombing produced a bizarre metal

Plus, have we already found life on Mars?                    

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July 31—It’s a hot take, but some scientists are convinced we already found evidence of life on Mars in the 1970s. Plus, an earth scientist found a completely new metallic material that was created from the 1945 bombing of Hiroshima, and geneticists uncover “ghost ancestors” in the human genome. After reading this newsletter, take our Friday quiz to test your knowledge of this week’s science news. (Today, that involves avocados.) —Emma Gometz, Newsletter Editor How are you liking this newsletter? Email newsletters@sciam.com anytime.

Top Stories

Has NASA already found life on Mars? In searches for past and present Martian life, some scientists say we’ve been too cautious to see what’s right in front of us Nadia Drake

Hundreds of never-before-seen ancient ‘earthworks’ discovered in the Amazon Many of these structures date to around C.E. 100–300, during the time of the Aquiry civilization, and may have been used for ceremonial purposes Jackie Flynn Mogensen

Travel with Scientific American Experience Yellowstone as a Winter Wonderland Reservations now open! This January, journey deep into Yellowstone National Park with your guide, Senior Desk Editor Andrea Thompson, for a spectacular week-long exploration of snowy landscapes, steaming geysers and roaming wildlife. Learn More

How a 99-year-old mathematician unraveled a century-old braid mystery Joan Birman popularized the Burau representation problem decades ago. Now she and two colleagues have a proof that reveals brand new insights into the geometry of braids Lyndie Chiou

The Hiroshima atomic bombing created a bizarre new material. Scientists just discovered it The extreme conditions of atomic bomb explosions create “uncontrolled microexperiments” that, in Hiroshima, forged a never-before-seen metallic alloy Mary Randolph

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Everyone alive may carry DNA from a ‘ghost lineage’ of human ancestors Scientists analyzing modern genomes may have found a long-lost branch of the human family tree Jacek Krywko

550 years later, scientists claim to have solved what killed Botticelli’s muse Italian Renaissance painter Sandro Botticelli painted Simonetta Vespucci as Venus rising from the waves. Now scientists think they’ve solved how she died Paolo Pozzilli, The Conversation US

Does physics allow time travel? Physicists, mathematicians and philosophers have been exploring the possibility of going forward to the future or back to the past Manon Bischoff

Europe’s heat waves are killing thousands—and wringing its soils dry The European continent is facing a dual reckoning this summer—extreme heat is killing thousands and draining its rivers, soils and reservoirs at a record pace Sanidhya Sharma

Mathematical ‘einstein’ tile works in the real world, to everyone’s surprise Discovered by an amateur mathematician in 2022, this strange construct can tile an infinite surface without repeating. But can it be useful in the real world? Joseph Howlett

Is buying lettuce off the table all summer? Thousands of people have gotten sick from Cyclospora. Experts can’t agree whether the end is in sight Mary Randolph

Math can help reduce traffic jams When the roads get crowded, many drivers start changing lanes. Mathematics suggests this intuition is typically wrong Randa Herzallah, The Conversation US

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