The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity
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Using ct instead of t results in both axes being measured in meters, for example, and the speed of light is depicted by lines of slope ±1 in spacetime diagrams, as is our usual convention.
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2016
American Association of Physics Teachers
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