Answer:
Einstein's greatest equation, E = mc2, is a triumph of the power and simplicity of fundamental physics. Matter has an inherent amount of energy to it, mass can be converted (under the right conditions) to pure energy, and energy can be used to create massive objects that did not exist previously. Thinking about problems in this way enabled us to discover the fundamental particles that make up our Universe, to invent nuclear power and nuclear weapons, and to discover the theory of gravity that describes how every object in the Universe interacts. And the key to figuring the equation out? A humble thought experiment, based on one simple notion: that energy and momentum are both conserved. The rest? It's just an inevitable consequence of the Universe working exactly as it does
The Hegira is the journey or migration of Muhammad (the Islamic prophet) and his followers from Mecca to Yathrib in 622. After getting a warning from a group he and his followers surreptitiously left his residence in Mecca to migrate to Yathrib which was 320 km north of Mecca. In his migration, he was followed by Abu Bakr who later became one of the Caliphs.
