Today in Science: Nuclear reactor on the moon?

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August 5, 2025—Fall bird migrations have begun. Also, did primordial black holes light up the early universe? And NASA's new aim to build a nuclear reactor on the moon.  —Andrea Gawrylewski, Chief Newsletter Editor TODAY'S NEWS A concept illustration showing NASA's Fission Surface Power Project on the moon. NASA NASA's acting administrator, Sean Duffy, issued a directive to expedite building a nuclear reactor on the moon. It might spur a lunar land grab. | 3 min read When she was just 17 years old, Hannah Cairo disproved the Mizohata-Takeuchi conjecture, breaking a four-decade-old mathematical assumption. This is how she did it. | 7 min read  Scientists have finally identified the mysterious disease killing sea stars for a decade. | 3 min read Fifty-eight people have been infected—and two have died—in a New York City outbreak of Legionnaires' disease. | 3 min read More News TOP STORIES Semipalmated plover (Charadrius semipalmatus). Jim Zipp/Science Source The Great Fall Migration Birds have started to fly south for the winter. Unlike spring migration, the fall exodus unwinds at a more leisurely pace. Birds might make more pit stops along the way, giving us more opportunities to see them. "Recently at a beach in Midcoast Maine, a friend and I came across a male Snowy Plover—a rare visitor to the East Coast—foraging for tiny invertebrates in the wrack," recounts resident bird lover and evolution editor, Kate Wong. Wherever you are, she says, you can observe this Great Migration.   How to watch: A number of tools can help you find good places to birdwatch. This bird migration forecast, created by Colorado State University and Cornell University, shows predicted nocturnal migrations from August 1 through November 15, 2025. They've also made a handy table of peak migration windows for U.S. cities. The U.S. weather surveillance network also has live migration maps of nocturnal bird migration, and a migration dashboard to see trends in your area.   How to I.D.: "Fall migration also brings an opportunity to hone your identification skills," writes Wong. Birds typically don duller colors and are less vocal now that they don't need to attract a mate. This makes many of them tougher to identify. Wong enjoys these field guides: The Sibley Guide to Birds and the related Sibley Birds app. "But you don't need to rely on these tools to enjoy fall migration," she writes. "Sometimes the best birding happens when you ditch your phone or camera and unplug so nothing can distract from the extraordinary creatures in front of you." —Andrea Tamayo, newsletter writer Primordial Black Holes The James Webb Space Telescope peered back in time to when the universe was only 200 million to 100 million years old and observed nine new light sources. Six of those light sources appear to have a redshift of 17 and three seem to have a redshift of 25, both which correlate to the very young universe.    Why this is interesting: The new sources of light suggest that galaxies formed in a much earlier period of the universe than astronomers thought possible. So are these newly found luminescences tied to stars or something else? A second group of researchers has proposed that the lights might be "primordial" black holes created right after the big bang that may have lit up the universe before the first stars. And so, the first objects to illuminate the early universe may not have been stars but rather hungry black holes that burst into existence mere seconds after the big bang itself.   What the experts say: Initially, these black holes would have started out small, "no larger than the size of an atom," says astrophysicist Allison Kirkpatrick of the University of Kansas. Although starting out tiny, after 100 million years, these black holes may have swelled to 10,000 times the mass of the sun, says Andrea Ferrara, an astrophysicist at the Superior Normal School (SNS) in Pisa, Italy, and co-author of the study that identified the new light sources.

EXPERT PERSPECTIVES Global governments have long recognized that international scientific cooperation is key to dealing with global problems such as nuclear weapons, pandemics, climate warming and misuses of artificial intelligence, Frank N. von Hippel, a research physicist and professor emeritus with Princeton's Program on Science and Global Security, wrote last November. "We do have secrets that must be protected," he says. "But unnecessary barriers will weaken us at least as much as our adversaries—especially where they make it more difficult for scientists to share ideas about how to make the world more safe and livable." | 4 min read More Opinion PUZZLER Can you unscramble this? Reassemble the cover of our March 1934 issue, showing streams of electricity from a Van de Graaf generator, which accompanies an article by Nikola Tesla about electrostatic generators' potential uses. ​   To celebrate Scientific American's 180th anniversary, we're publishing a jigsaw every weekday to show off some of our most fascinating magazine covers over the years. Take a tour here through the covers so far. More Jigsaws Want to dive deeper into the science that interests you? Consider a subscription to Scientific American. Today in Science readers get special discounts! Frank N. von Hippel's essay summarized above is an important one. Science transcends politics, and there's a long history of scientists keeping their international collaborations going despite their respective governments being at odds. Especially for global problems that affect every person on the planet, international sharing of insights, ideas and sparks of creativity is crucial.  Thanks for reading Today in Science. Send any feedback on this newsletter to: newsletters@sciam.com. See you tomorrow!   —Andrea Gawrylewski, Chief Newsletter Editor

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