| dbo:abstract |
The term physical constant expresses the notion of a physical quantity subject to experimental measurement which is independent of the time or location of the experiment. The constancy (immutability) of any "physical constant" is thus subject to experimental verification. Paul Dirac in 1937 speculated that physical constants such as the gravitational constant or the fine-structure constant might be subject to change over time in proportion of the age of the universe.Experiments conducted since then have put upper bounds on their time-dependence. This concerns the fine-structure constant, the gravitational constant and the proton-to-electron mass ratio specifically, for all of which there are ongoing efforts to improve tests on their time-dependence. The immutability of these fundamental constants is an important cornerstone of the laws of physics as currently known; the postulate of the time-independence of physical laws is tied to that of the conservation of energy (Noether theorem), so that the discovery of any variation would imply the discovery of a previously unknown law of force. In a more philosophical context, the conclusion that these quantities are constant raises the question of why they have the specific value they do in what appears to be a "fine-tuned universe", while their being variable would mean that their known values are merely an accident of the current time at which we happen to measure them. (en) A variação temporal das constantes fundamentais é uma manifestação da violação do de Einstein, exigido por teorias unindo a gravitação com as interações forte e eletrofraca. O termo constante física expressa a noção de uma quantidade física sujeita a medição experimental que é independente do tempo ou local do experimento. A constância (imutabilidade) de qualquer "constante física" é, portanto, sujeita a verificação experimental. Em um contexto mais filosófico, a conclusão de que essas quantidades são constantes levanta a questão de por que elas têm o valor específico que elas fazem no que parece ser um "universo afinado", enquanto serem variáveis significariam que seus valores conhecidos são meramente um acidente do tempo atual em que nós os medimos. (pt) |
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https://arxiv.org/abs/0801.1935 https://web.archive.org/web/20160401212131/http:/relativity.livingreviews.org/Articles/lrr-2011-2/download/lrr-2011-2Color.pdf |
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| rdfs:comment |
The term physical constant expresses the notion of a physical quantity subject to experimental measurement which is independent of the time or location of the experiment. The constancy (immutability) of any "physical constant" is thus subject to experimental verification. (en) A variação temporal das constantes fundamentais é uma manifestação da violação do de Einstein, exigido por teorias unindo a gravitação com as interações forte e eletrofraca. O termo constante física expressa a noção de uma quantidade física sujeita a medição experimental que é independente do tempo ou local do experimento. A constância (imutabilidade) de qualquer "constante física" é, portanto, sujeita a verificação experimental. (pt) |
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Time-variation of fundamental constants (en) Variação temporal das constantes fundamentais (pt) |
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