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June 17, 2025—Astronomers discover belching black holes. Plus, an AI that translates cat meows and the iNaturalist community flips out. —Andrea Gawrylewski, Chief Newsletter Editor | | - The nonprofit iNaturalist announced that it received a $1.5-million grant from Google's philanthropic arm to develop generative AI tools for species identification. Users did not take the news well. | 3 min read
- Drones are a common feature of modern warfare. From Iran's Shahed attack to Ukraine's Operation Spiderweb, this is how drone swarms work. | 7 min read
- Even without subsidies, renewable energy is competitive with power from gas and coal, according to this year's report from the investment bank Lazard. | 3 min read
- Several AI-based tools are under development to translate cat vocalizations. The research so far suggests that house cats wield a far richer vocabulary than once thought (well, except by their owners). | 7 min read
| | Black holes devour stars. Within a black hole's event horizon, the gravitational pull is so strong nothing can escape, and stars that wander too close are shredded, spitting mass and light outward in the process. But sometimes, years after a star is destroyed, some black holes spew out material again, like a cosmic burp of light. Physicists surveyed two dozen black holes that had experienced an initial brightening event associated with star destruction. After years of darkness, the team discovered that 10 of the black holes were bright again in radio waves.
Why this is interesting: When a black hole shreds a star, one of a few things can occur. In rarer cases, the material gets funneled into a jet that launches outward at nearly the speed of light (called relativistic outflow, at left below). And star material almost always sloshes around in a disk around the black hole (called an accretion disk) where friction causes energy and light to blaze outward (below, right). Scientists long thought that feasting black holes released a single surge of light. But recent findings show a second burst, nearly 1,000 days after the initial shredding, can be common. | | What the experts say: What causes these strange cases of black hole indigestion? Perhaps the accretion disk around the black hole forms much later than we'd previously assumed, writes Yvette Cendes, a professor in the department of physics and astronomy at the University of Oregon. "Or possibly the black holes are creating unusual density fluctuations in their environments. The flares could be caused by interacting dust clouds, or maybe a cocoon of material around the black hole delays the flow of radio emission until later." | | | | |
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- Global rates of death due to complications from lead poisoning have been steadily on the rise, writes Aaron Specht, an assistant professor of health physics at Purdue University. But health departments and the CDC currently lack the infrastructure to deploy new testing technology in communities. "People concerned about lead exposure should request a blood lead test from their doctor. Parents of young children should proactively ask pediatricians to conduct lead screening. If you live in an old home, especially one with peeling paint, you can contact your local health department to test for possible lead paint," he says. | 6 min read
| | Black holes are invisible. Because no light can escape from within the event horizon, scientists speculated for decades what a black hole might actually look like. Finally, in 2019, using a virtual Earth-size telescope, astronomers revealed the first image of the black hole at the center of the galaxy Messier 87. The black hole itself is in shadow, surrounded by fiery orange matter circling the event horizon. In 2022, astronomers pointed the same telescope at the heart of the Milky Way, again capturing a picture of a shadowy center surrounded by glowing material. We may never see its face, but a black hole centers the galaxy our solar system orbits, taking us along for the ride. | | —Andrea Gawrylewski, Chief Newsletter Editor | | | | |
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