SIGNAL: A seismic wave from Japan's 2011 magnitude-9 earthquake travelled nearly 2,900 kilometres down to Earth's core, bounced back to the surface 13 minutes later, and shifted the entire country eastward by roughly six millimetres at the same instant — in the first - Space Daily

A seismic wave from Japan's 2011 magnitude-9 earthquake travelled nearly 2,900 kilometres down to Earth's core, bounced back to the surface 13 minutes later, an...