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?

#YourDailyEquation with Brian Greene offers brief and breezy discussions of the most pivotal equations of the ages. Even if your math is a bit rusty, these accessible and exciting stories …

Elaine Fuchs pioneered the field of reverse genetics—studying proteins and learning what they do, and how they do it, in order to identify the genetic disease they cause when they …

A second doesn’t always feel like a second—time can seem to slow down if you’re riding a death-defying roller coaster, or speed up while you’re having a night out on the town. But just what’s going on inside our heads to skew our perception of time?

Beyond Einstein: Gravitational Echoes. Just as sound waves can echo off a distant rockface, light waves can echo off of black holes. Renowned researchers Erin Kara and Shep Doeleman join …

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.