Scientific American.com

As large language models like Claude 4 express uncertainty about whether they are conscious, researchers race to decode their inner workings, raising profound questions about machine awareness, ethics and the risks of uncontrolled AI evolution

A study of nearly 1,000 people showed that brain aging was not linked to infection status

Hundreds of staffers at the National Institutes of Health, Environmental Protection Agency, NASA and the National Science Foundation have signed public letters to leadership opposing the direction in which the agencies are headed

If you’re seeking a summer read, Scientific American has some fantastic fiction and notable nonfiction to recommend.

Ozzy Osbourne, lead singer of Black Sabbath, has died at age 76. He said he had been previously diagnosed with a form of Parkinson’s disease linked to the gene PRKN

The largest yet study on a four-day workweek included 141 companies, 90 percent of which retained the arrangement at the end of the six-month experiment

My lawsuit in Hawaii lays out the safety issues in OpenAI’s products and how they could irreparably harm both Hawaii and the rest of the U.S.

A declaration of dissent from past and present NASA employees warns that science and safety are at risk and joins similar documents from staff at other federal science agencies

A hormone-free pill, called YCT-529, that temporarily stops sperm production by blocking a vitamin A metabolite has just concluded its first safety trial in humans, getting a step closer to increasing male contraceptive options

Optimists have similar patterns of brain activation when they think about the future—but pessimists are all different from one another, a brain scan study suggests

In only its second year, the International Logic Olympiad is already booming as logic becomes more and more crucial in our ever changing world

Humid heat is blanketing the eastern U.S. this week, exacerbated by “corn sweat” in the Midwest

A SkyWest pilot’s last-second decision could have prevented a collision that air-traffic controllers may not have foreseen

Acknowledging the limits of one’s own knowledge could be as important a signal of expertise as credentials and confidence

The Langlands program has inspired and befuddled mathematicians for more than 50 years. A major advance has now opened up new worlds for them to explore

This episode of Science Quickly goes on an archival adventure in Scientific American’s July 1925 issue.

Discover why some puzzles stump supersmart AIs but are easy for humans, what this reveals about the quest for true artificial general intelligence—and why video games are the next frontier

A 72 percent reduction in federal funding is devastating to math research. The American Mathematical Society is offering $1 million in backstop grants—but it’s likely not enough

Why do computers only work with the numbers 0 and 1? There are machines that process three digits with more efficiency than you might expect

It’s certainly possible to consume water sourced from the icy rings of Saturn, but doing so safely may require extra steps