Waves close wavesVibrations that transfer energy from place to place without the transference of matter. - including sound and light - can be reflected at the boundary between two different materials.

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 ...

The method involves stitching together many thin “slices” of light reflecting off an object.