Entropy and Time
Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
Entropy 2020, 22(4), 430; https://doi.org/10.3390/e22040430
Received: 22 February 2020 / Accepted: 8 April 2020 / Published: 10 April 2020
(This article belongs to the Special Issue Time and Entropy)
The idea that entropy is associated with the “arrow of time” has its roots in Clausius’s statement on the Second Law: “Entropy of the Universe always increases.” However, the explicit association of the entropy with time’s arrow arises from Eddington. In this article, we start with a brief review of the idea that the “increase in entropy” is somehow associated with the direction in which time increases. Then, we examine three different, but equivalent definitions of entropy. We find that none of these definitions indicate any hint of a relationship between entropy and time. We can, therefore, conclude that entropy is a timeless quantity. We also discuss the reasons as to why some scientists went astray in associating entropy with time’s arrow. Finally, we shall discuss Boltzmann’s H-Theorem, which is viewed by many as a proof of the Second Law of Thermodynamics. View Full-Text
Keywords: arrow of time; entropy; Shannon’s measure of information; second law of thermodynamics; H-theorem; H-function
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MDPI and ACS Style
Ben-Naim, A. Entropy and Time. Entropy 2020, 22, 430.
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Ben-Naim A. Entropy and Time. Entropy. 2020; 22(4):430.Chicago/Turabian Style
Ben-Naim, Arieh. 2020. "Entropy and Time." Entropy 22, no. 4: 430.
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