mass-energy equivalence

Scientific  

1. An equation derived from Einstein's theory of Special Relativity expressing the relationship between the mass and energy of objects with mass. The equation is E = mc ², where E is the energy of the object in joules, m is its relativistic mass in kilograms, and c is the speed of light (approximately 3 × 10 ⁸ meters per second). Mass-energy equivalence entails that the total mass of a system may change, although the total energy and momentum remain constant; for example, the collision of an electron and a proton annihilates the mass of both particles, but creates energy in the form of photons. The discovery of mass-energy equivalence was essential to the development of theories of atomic fission and fusion reactions.

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Example Sentences

Besides mass-energy equivalence and gravitational time dilation, a third concept which emerges from the mathematics of relativity is something known as the metric field.

From Economist

Granted, it’s blurry, but could this be the only photograph of Einstein’s derivation of the mass-energy equivalence? i09 has more, including a link to the relevant 2007 paper deciphering the physicist’s scribblings.

From Scientific American