Do animals fall for optical illusions? It’s complicated.

Guppies are highly susceptible to the Ebbinghaus illusion. Ring doves? Not so much. Chances are you’ve encountered some version of the “Ebbinghaus illusion,” in which a central circle appears to be smaller when encircled by larger circles and seems larger when surrounded by smaller circles. It’s an example of…

Dead Ends is a fun, macabre medical history for kids

Ars chats with co-authors Lindsey Fitzharris and Adrian Teal about their delightful new children’s book. In 1890, a German scientist named Robert Koch thought he’d invented a cure for tuberculosis, a substance derived from the infecting bacterium itself that he dubbed Tuberculin. His substance didn’t actually cure anyone, but…

NASA’s next Moonship reaches last stop before launch pad

Preparations for the Artemis II mission continue despite the federal government shutdown. The Orion spacecraft, which will fly four people around the Moon, arrived inside the cavernous Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida late Thursday night, ready to be stacked on top of its rocket…

Lead poisoning has been a feature of our evolution

A recent study found lead in teeth from 2 million-year-old hominin fossils. Our hominid ancestors faced a Pleistocene world full of dangers—and apparently one of those dangers was lead poisoning. Lead exposure sounds like a modern problem, at least if you define “modern” the way a paleoanthropologist might: a…