For all we understand about the universe, 96% of what’s out there still has scientists in the dark. Astronomical observations have established that familiar matter—atoms—accounts for only 4% of the weight of the cosmos. The rest—dark matter and dark energy—is invisible to our telescopes.

We’ve discovered thousands of exoplanets, but what about exomoons? Astronomer David Kipping joins Brian Greene to explore the ongoing search for exomoons—lesser-known, but intriguing potential habitats for life beyond Earth. …

Stephen Wolfram joins Brian Greene to explore whether the ultimate theory of the universe might emerge from a computationally simple framework. This program is part of the Big Ideas series, …

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 …

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?

Microbiologist Hazel Barton goes spelunking in sticky mud, camping underground, and rope climbing in a atrium—all to research cures for antibiotic-resistant diseases. Episode filmed live at the 2009 World Science …