Article
Article
Arrow of time
Article By:
Atkins, P. W. Department of Chemistry, Lincoln College, Oxford University, Oxford, United Kingdom.
Last reviewed:October 2019
DOI:https://doi.org/10.1036/1097-8542.757389
The uniform and unique direction associated with the apparent inevitable flow of time into the future. There appears to be a fundamental asymmetry in the universe. Yet herein lies a paradox, for all the laws of physics, whether they are the equations of classical mechanics, classical electromagnetism, general relativity, or quantum mechanics, are time-reversible in the sense that they admit solutions in either direction of time. This reversibility raises the question of how these fundamentally time-symmetrical equations can result in the perceived asymmetry of temporally ordered events.
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