Alien life has been a mainstay and fascination of science fiction, but who–or what–might actually be out there: biological life, artificial intelligence, or some combination of both? It took only …

Nowadays, the tools for tracing your family tree have advanced far beyond looking back at names in the family Bible or compiling a scrapbook of paper records. Using your genetic information to find long-lost relatives is easier and cheaper than ever before—and scientists are looking to push the technology even further by analyzing our skin and facial features.

Though many animals display cooperative behavior, human cooperation is distinct. Alan Alda hosts E.O. Wilson, Sarah Hrdy and other leading evolutionary biologists, anthropologists and humanitarians as they examine the origins and evolution of human cooperative behavior.

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.

Nobel Laureate Sir Paul Nurse joins Brian Greene for a conversation about the fundamental ideas in biology explored in his new book, What Is Life? Five Great Ideas in Biology. …

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 …