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E = mc² is the world’s most famous equation—a mathematical formula with the power to transcend the barriers of language and culture. Matching its popularity is its deceiving complexity. Its symbols, although easily recognized, embody concepts contrary to the way things seem to be.

On Sept. 27, 1905, Albert Einstein‘s paper “Does the Inertia of a Body Depend Upon Its Energy Content?” was published. It was the last of four papers he submitted that year to the journal Annalen der Physik. The first explained the photoelectric effect, the second offered experimental proof of the existence of atoms, and the third introduced the theory of special relativity. The last and final paper of the series introduced m = E/c², which was later streamlined to its now instantly recognizable form.

That year, 1905, remains one of the most significant in the history of physics. Before Einstein, entities such as time and space and mass and energy were separate. But by bringing these then seemingly unrelated elements together, first in the concept of space-time and immediately thereafter in the equation E = mc², Einstein completed his theory of special relativity. Special relativity is perhaps one of the least intuitive theories ever conceived in the history of science, yet it is central to physics.

In E = mc² Einstein concluded that mass (m) and kinetic energy (E) are equal, since the speed of light (c²) is constant. In other words, mass can be changed into energy, and energy can be changed into mass. The former process is demonstrated by the production of nuclear energy—particles are smashed and their energy is captured. The latter process, the conversion of energy into mass, is demonstrated by the process of particle acceleration, in which low-mass particles zipping through a device collide to form larger particles.

The inclusion of the speed of light in Einstein’s equation was based on the principles of classical mechanics and electromagnetic radiation, the latter of which is pure energy. Electromagnetic radiation is constant—it always travels at the speed of light, or 186,000 miles/sec (300,000 km/sec).

E = mc² was a product of special relativity, which itself seemed enigmatic to Einstein’s colleagues and a complete mystery to just about everyone else.

 

 

Sumber: www.britannica.com/.../e-mc2-the-unforge...‎