twin paradox

noun
1.
a phenomenon predicted by relativity. One of a pair of identical twins is supposed to live normally in an inertial system whilst the other is accelerated to a high speed in a spaceship, travels for a long time, and finally returns to rest beside his twin. The travelled twin will be found to be younger than his brother
Contemporary definitions for twin paradox
noun

a supposed paradox in relativity theory that if one of a pair of twins journeys near the speed of light and returns, that win will have aged less than the twin left behind

Usage Note

science

twin paradox in Culture

twin paradox definition


An effect predicted by the general theory of relativity: if one of a pair of twins remains on Earth, and the other travels in a rocket at a speed near the speed of light, the traveling twin will be younger than the earthbound twin upon returning to Earth. This effect has been verified experimentally by measurements with atomic clocks.