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twin paradox

noun

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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
twin paradox in Culture

twin paradox

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.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.