fifth force

fifth force

n.

Any of the hypothetical forces believed to cause bits of matter to repel each other but not to be strong enough to counteract gravity.

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fifth force

n

(Physics / General Physics) a hypothetical non-Newtonian repulsive component of the force of gravity, postulated as an addition to the four known fundamental forces (gravitational, electromagnetic, strong, and weak)

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fifth force  (ffth)

Any of various hypothetical, very weak forces thought to cause bodies to repel each other. Such forces are occasionally considered as a solution to unexpected deviations in the measured value of the gravitational constant or to explain the apparent acceleration of very distant galaxies away from earth.