Scientific American Magazine

Baffled by the expansion of the universe? You're not alone. Even astronomers frequently get it wrong

Wild zebra, asses and horses are being killed for meat, medicine and money. Combined with vanishing habitats and naturally slow reproduction, such predation threatens remaining populations

Although fleets of fuel-cell prototypes are hitting the streets, basic technical and market obstacles must be hurdled before the clean, hydrogen-powered cars reach dealer showrooms

A bold new hypothesis suggests that our ancestors' farming practices kicked off global warming thousands of years before we started burning coal and driving cars

Teasing out the causes of this autoimmune disorder is a daunting challenge. But the payoff should be better, more specific treatments

Nikola Tesla, the father of today's AC electrical system and other key inventions, often failed to bring his visionary ideas to real-world fruition

"Episims" unleashes virtual plagues in real cities to see how social networks spread disease. That knowledge might help stop epidemics