While the concept of time travel has long captured public imagination, modern physics actually approaches time in a much more subtle manner. Instead of moving people or objects through history, ...

The top layer represents the location of the sound source and the path of sound propagation (A). The bottom layers represent convergence zones with different sound propagation paths (B-F). Sound waves ...

Like stretch marks left on skin that expanded too quickly or cracks embedded in freezing ice, cosmic strings are artifacts of ...