mass-energy equivalence

mass-en·er·gy equivalence (msnr-j)

n.

The physical principle that a measured quantity of energy is equivalent to a measured quantity of mass. The equivalence is expressed by Einstein's equation, E = mc², where E represents energy, m the equivalent mass, and c the speed of light.

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mass-energy equivalence

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 = mc², 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 × 10⁸ 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.

Thesaurus

Noun

1.

mass-energy equivalence - (physics) the principle that a measured quantity of mass is equivalent (according to relativity theory) to a measured quantity of energy principle, rule - a rule or law concerning a natural phenomenon or the function of a complex system; "the principle of the conservation of mass"; "the principle of jet propulsion"; "the right-hand rule for inductive fields" natural philosophy, physics - the science of matter and energy and their interactions; "his favorite subject was physics"