We spend a third of our lives asleep. Every organism on Earth—from rats to dolphins to fruit flies to microorganisms—relies on sleep for its survival, yet science is still wrestling with a fundamental question: Why does sleep exist?

Every successful scientist seems to have a “once in a blue moon” discovery during his or her lifework: an accident or epiphany that unexpectedly leads to a serendipitous breakthrough. Geneticist …

Leading physicist Raphael Bousso joins Brian Greene to explore the almost unreasonable capacity of our theories of gravity to give deep insights into quantum physics. This program is part of …

What makes Mona Lisa’s smile so intriguing? What makes Picasso’s portraits so compelling? Kurt Andersen hosts artists Chuck Close and Devorah Sperber, with neuroscientists Margaret Livingstone, Chris Tyler and Ken Nakayama, as they examine the power of brain imaging technology to illuminate how we perceive the most intimate yet public of features, the human face.

After a storied career with 5 spaceflights (including three trips to fix the Hubble Space Telescope), NASA astronaut John Grunsfeld now helms the space agency’s scientific missions. He helps shepherd …

This video is part of our Brilliant Breakthroughs series: our new 20-episode mini-series exploring the “Eureka!” moments and proud accomplishments of the greatest scientific minds of our time. Join us …