Sexuality and gender play a profound role in shaping identity, but for much of human history how they are determined has remained obscure. How does sexual orientation develop? What is it? Can it be changed?

Marcia Bartusiak joins Kip Thorne, Laura Danly and Rainer Weiss to demonstrate how two observatories on opposite sides of the country, called LIGO (Laser Interferometer Gravitational-wave Observatory), may open a new window on observing the cosmos—one based not in light but in gravity.

What if we could peer into a brain and see guilt or innocence? Brain scanning technology is trying to break its way into the courtroom, but can we—and should we—determine criminal fate based on high-tech images of the brain?

What made Albert Einstein one of the greatest scientific geniuses the world has ever known? His scientific breakthroughs revolutionized the way we understand the universe.

Are there limits to the human lifespan? Is it possible to stop the process of aging? On average, humans now live far longer than at any point in our history …

Can marching ants, schooling fish, and herding wildebeests teach us something about the morning commute? Robert Krulwich guides this unique melding of mathematics, physics, and behavioral science as Mitchell Joachim, Anna Nagurney and Iain Couzin examine the creative and sometimes counter intuitive solutions to one of the modern world’s most annoying problems.

The notion of a “tortured genius” or “mad scientist” may be more than a romantic aberration. Research shows that bipolar disorder and schizophrenia correlate with high creativity and intelligence, raising tantalizing questions: What role does environment play in the path to mental illness?

Not long ago, the idea of a computer beating a human at chess was the stuff of science fiction. But some of the most creative programmers of the 1980s and 90s were determined to make it a reality. And they did.