Understand the physics behind total internal reflection and why light can become completely trapped inside a medium. This video explains the conditions required for total internal reflection, the role ...

Introduction Can you imagine a bouncy ball that could bounce back and forth between two walls, infinitely—that is, forever? Wouldn't that be amazing? What if, instead of a ball, light was bouncing ...

Can we turn back time? Ask a savvy physicist, and the answer will be “it depends.” Schemes for retrograde time travel abound but usually involve irreconcilable paradoxes and rely on outlandish ...