 The inner core is like a heat engine, essentially, that heats our planet. As the planet cools, the inner core starts solidifying out of the outer core. This study confirms the existence of shear waves or j-waves in the inner core. This is a confirmation that the earth's inner core, the deepest shell of the earth, is solid. We concentrate on the waveforms between three and ten hours after large earthquakes. The green dots are receivers on the surface of the planet and the red dots are large earthquakes. It's like a fingerprint of the earth. The inner core could be thought of as the deepest time capsule we are trying to probe with these new techniques. This is where the magnetic field of the earth is generated and maintained. The geomagnetic field represents a shield around our planet that protects us from a cosmic radiation, without which the life on earth's surface would be impossible. We are in a mapping stage when it comes to the earth's surface, but we are still in the discovery stage when it comes to the deep earth structure. The earth holds many more secrets that are to be discovered.