SA Special Editions

Studies of how the human engine burns calories help to explain why physical activity does little to control weight—and how our species acquired some of its most distinctive traits

Mixotrophs, tiny sea creatures that hunt like animals but grow like plants, can change everything from fish populations to rates of global warming

Deep oceans were thought to hold life’s origins. New evidence points instead to an active volcanic landscape

Ancient stone tools from Kenya shatter the classic story of when and how humans became innovators

A technical revolution provides insight into how the brain links memories, a process critical for understanding and organizing the world around us

Why is the expansion of the universe accelerating? After two decades of study, the answer is as mysterious as ever, but the questions have become clearer

A hidden population of black holes born less than one second after the big bang could solve the mystery of dark matter

Brain deficits and more torment many virus survivors in Liberia. The top suspects are hidden viral remnants and immune system overreactions

Our neighborhood of planets was not created slowly, as scientists once thought, but in a speedy blur of high-energy crashes, destruction and rebuilding

Long thought impossible, preservation of fossil pigments is allowing scientists to reconstruct extinct organisms with unprecedented accuracy—a feat that is yielding surprising insights into the lives they led

How a naturalist’s observations in the wilds of British Columbia inspired a scientist to discover hidden symbioses—overturning 150 years of accepted scientific wisdom

Physicists who have revived experiments from 50 years ago say nerve cells communicate with mechanical pulses, not electric ones

Scientists are on the threshold of crossing a sharp ethical line: permanently altering the human genetic code

Much of Noam Chomsky’s revolution in linguistics—including its account of the way we learn languages—is being overturned

Two technologies may be on the verge of surpassing even the most powerful digital computers in a year or so, but key challenges remain unsolved