We also find that the return of the term to the forefront of modern cosmology did not occur as an abrupt paradigm shift due to one particular set of observations, but as the result of a number of empirical advances such as the measurement of present cosmic expansion using the Hubble Space Telescope, the measurement of past expansion using type SN Ia supernovae as standard candles, and the measurement of perturbations in the cosmic microwave background by balloon and satellite. We find that the cosmological constant was never truly banished from theoretical models of the universe, but was marginalized by astronomers for reasons of convenience. We consider historical and philosophical aspects of the cosmological constant over four main epochs (i) the use of the term in static cosmologies (both Newtonian and relativistic): (ii) the marginal-ization of the term following the discovery of cosmic expansion: (iii) the use of the term to address specific cosmic puzzles such as the timespan of expansion, the formation of galaxies and the redshifts of the quasars: (iv) the re-emergence of the term in today's Λ-CDM cosmology. First introduced to the general theory of relativity by Einstein in 1917 in order to describe a universe that was assumed to be static, the term fell from favour in the wake of the discovery of the expanding universe, only to make a dramatic return in recent times. Send us feedback.We present a centennial review of the history of the term known as the cosmological constant. These example sentences are selected automatically from various online news sources to reflect current usage of the word 'entropy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors.
Henry Wismayer, Anchorage Daily News, 30 Aug. 2022 The ambient entropy, which manifested here in the chaotic climate, the shriveling lake, the junk of human settlements laid waste, felt like the ultimate rebuke to our myopia. Geek's Guide To The Galaxy, WIRED, 9 Sep. 2022 Sabine Hossenfelder on entropy: Entropy is a very anthropomorphic quantity. 2022 Hawking's final paper revisited black hole entropy and the no-hair concept. 2022 There’s clearly something going on linking area, entropy and information. 2022 The first major clue came in the late 1990s when theoretical physicist Juan Maldacena calculated the entropy of a black hole. 2022 Contrast this with the entropy of a more traditional system-say, a gas in a box.Įdgar Shaghoulian, Scientific American, 22 Aug. 2022 Featureless equilibrium is the state of maximum entropy, toward which the Second Law drives us.įrank Wilczek, WSJ, 1 Sep. Recent Examples on the Web Naert plans to work with theorists to better understand what this type of temperature means, along with measuring and understanding the role of entropy in his device.
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