How much brain do you need to be smart? Bees and ants perform marvels as colonies, though each insect has barely any brain. And plants—with no brain at all—exhibit behaviors …

It’s an old question: What is consciousness? Today, sophisticated brain imaging technologies, clinical studies, as well as the newfound ability to listen to the whisper of even an individual nerve cell, are bringing scientists closer than ever to the neurobiological basis of consciousness.

What are the special challenges, pitfalls, opportunities and rare triumphs of seeking and synthesizing the essence of someone whose passion—quantum physics, number theory, nucleic acids, atomic species, computational design, gravitational phenomena—is so thoroughly foreign to the concerns of everyday life?

Albert Einstein shattered previous ideas about time, but left many pivotal questions unanswered: Does time have a beginning? An end? Why does it move in only one direction? Is it real, or something our minds impose on reality?

Astronomer Jill Tarter leads the charge to search for intelligent life on other planets by listening to clues from over 40 radio telescopes. Episode filmed live at the 2010 World …

The inflationary theory of cosmology, an enduring theory about our universe and how it was formed, explains that just after the Big Bang, the universe went through a period of rapid expansion. This theory has been critical to understanding what’s going on in the cosmos today.