Balance of nature: second law of thermodynamics (Introduction)

by David Turell , Tuesday, June 18, 2024, 17:44 (157 days ago) @ David Turell

Not proven, but as observed:

https://www.sciencenews.org/article/disorder-thermodynamics-second-law

"For centuries, physicists have been identifying laws of nature that are invariably unbreakable. Those laws govern matter, motion, electricity and gravity, and nearly every other known physical process. Nature’s laws are at the root of everything from the weather to nuclear weaponry.

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"It is widely cited as inviolable and acclaimed as applicable to everything. It guides the functioning of machines, life and the universe as a whole. Yet scientists cannot settle on one clear way of expressing it, and its underlying foundation has evaded explanation — attempts to prove it rigorously have failed. It’s known as the second law of thermodynamics. Or quite commonly, just the Second Law.

"In common (oversimplified) terms, the Second Law asserts that heat flows from hot to cold. Or that doing work always produces waste heat. Or that order succumbs to disorder. Its technical definition has been more difficult to phrase, despite many attempts. As 20th century physicist Percy Bridgman once wrote, “There have been nearly as many formulations of the second law as there have been discussions of it.”

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"In the two centuries since its birth, the Second Law has proved equally valuable for technological progress and fundamental science. It underlies everyday processes from cooling coffee to air conditioning and heating. It explains the physics of energy production in power plants and energy consumption in cars. It’s essential to understanding chemical reactions.

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"Carnot’s key insight was that heat produced motion for doing work by dropping from a high temperature to a lower temperature (in the case of steam engines, from the boiler to the condenser). “The production of motive power is then due in steam-engines not to an actual consumption of caloric, but to its transportation from a warm body to a cold body,” he wrote.

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"Heat is a manifestation of the motion of molecules. Nevertheless his findings remained correct — the Second Law applies no matter what substance an engine uses or what the actual underlying nature of heat is. Maybe that’s what Einstein had in mind when he called thermodynamics the scientific achievement most likely to stand firm as further advances rewrote humankind’s knowledge of the cosmos.

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"It became known as the Second Law because during this time, other work had established the law of conservation of energy, designated the first law of thermodynamics. Conservation of energy merely meant that the amount of energy involved in physical processes remained constant (in other words, energy could be neither created nor destroyed). But the Second Law was more complicated. Total energy stays the same but it cannot all be converted to work — some of that energy is dissipated as waste heat, useless for doing any more work.

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" In the meantime, Clausius introduced the concept of entropy to quantify the transformation of useful energy into useless waste heat — providing yet another way of expressing the Second Law. If the First Law can be stated as “the energy of the universe is constant,” he wrote in 1865, then the Second Law could be stated as “the entropy of the universe tends to a maximum.”

"Entropy, roughly, means disorder. Left to itself, an orderly system will degenerate into a disorderly mess. More technically, temperature differences in a system will tend to equalize until the system reaches equilibrium, at a constant temperature.

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"Some recent efforts to verify the Second Law invoke Landauer’s emphasis on erasing information, which links the Second Law to information theory. In a recent paper, Shintaro Minagawa of Nagoya University in Japan and colleagues assert that merging the Second Law with information theory can secure the law’s foundation. (my bold)

“'The second law of information thermodynamics,” they write, “can now be considered a universally valid law of physics.” (my bold)

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"...a 2020 review in the journal Entropy concludes that no such challenges to the Second Law have yet succeeded. “In fact, all resolved challengers’ paradoxes and misleading violations of the Second Law to date have been resolved in favor of the Second Law and never against,” wrote thermodynamicist Milivoje M. Kostic of Northern Illinois University in DeKalb. “We are still to witness a single, still open Second Law violation, to be confirmed.'”

Comment: the Second Law has a long history which says a heat source cannot create all of its energy into work as some will always be lost. Each living organism is a closed system using heat to survive, either environmental heat or self-created, against the entropy outside of it, while aging creates its own form of entropy.