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"The discrimination between cause and effect depends on times arrow and can only be settled by reference to entropy."
Entropy (thermodynamics)He sat in the window thinking. Man has a for order. Keys in one pocket — Entropy (thermodynamics)
"He sat in the window thinking. Man has a for order. Keys in one pocket, change in another. Mandolins are tuned G D A E. The physical world has a tropism for disorder, entropy. Man against Nature . . . the battle of the centuries. Keys yearn to mix with change. Mandolins strive to get out of tune. Every order has within it the germ of destruction. All order is doomed, yet the battle is worth while."
Entropy (thermodynamics)
Entropy (thermodynamics)
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Entropy is a thermodynamic state variable that quantifies the probabilistic distribution of accesible microstates in a system. The term and the concept are used in diverse fields, from classical thermodynamics, to the microscopic description of nature in statistical physics, and the principles of information theory. It has found far-ranging applications in chemistry and physics, in biological syst
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"Because entropy is not really a classical quantity, we must build quantum mechanics into the definition. ... It suffices to define entropy as the logarithm of the number of quantum states accessible to a system."
Entropy (thermodynamics)Quote
"Entropy is the price of structure."
Entropy (thermodynamics)Quote
"Investigations of the entropy of substances at low temperatures have produced very important information regarding the structure of crystals, the work of Giauque and his collaborators being particularly noteworthy. For example, the observed entropy of crystalline hydrogen shows that even at very low temperatures the molecules of orthohydrogen in the crystal are rotating about as freely as in the gas; ... subsequent to this discovery the phenomenon of rotation of molecules in crystals was found to be not uncommon."
Entropy (thermodynamics)Quote
"Is the random element... the only feature of the physical world which can furnish time with an arrow? ...Nothing in the statistics of an assemblage can distinguish a direction of time when entropy fails to distinguish one. ...[T]his law was only discovered in the last few years ...It is accepted as fundamental in ...atoms and radiation and had proved to be one of the most powerful weapons of progress in such researches. It does not seem to be... deducible from the second law..."
Entropy (thermodynamics)Quote
"The most common way to describe entropy is as disorder... associated with things becoming more mixed, random and less ordered, but... the best way to think about entropy is as the tendency of energy to spread out. ...Most of the laws of physics work... the same... forwards or backwards in time. ...So how does this clear time dependence arise? ...[T]his is where Ludwig Boltzmann made an important insight. Heat flowing from cold to hot is not impossible, its just improbable. ...In everyday solids there are about 100 trillion trillion atoms and even more energy packets, so heat flowing from cold to hot is just so unlikely that it never happens. ...[I]f the ...tendency is to spread out and for things to get messier, then how is it possible to have ...air conditioning, where the cold interior gets cooler and the hot exterior gets hotter? Energy is going from cold to hot, decreasing the entropy of the house. ...[T]his ...is only possible by increasing the entropy a greater amount ...at a power plant ...heating up the environment ...and creating waste heat in the fans and compressor [of the air conditioner]. ...How is there any structure left on earth? ...[I]f the earth were a the energy would spread out completely, meaning all life would cease, everything would decay and mix, and ...reach the same temperature. But luckily the earth is not a closed system, because we have the sun."
Entropy (thermodynamics)