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The law states that entropy increases in isolated systems. Let us take a cell, as an example of a live organism. If you isolate a cell, it will die, and the entropy of the isolated system will increase , as an isolated cell cannot live. All organisms live by continuously decreasing their own entropy and increasing the entropy of the surroundings, ...


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You've overlooked gravitational entropy. The entropy of a black hole horizon is given by: $$ S = \frac{kA}{4 \ell_p^2} $$ where $A$ is the area of the horizon, $k$ is Boltzmann's constant and $\ell_p$ is Planck's constant. This entropy is absolutely huge, so if you take a uniformly distributed gas in thermal equilibrium and concentrate it into a black ...


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Entropy is a natural tendency of the Universe to fall apart into disorder. In a reversible process, an increase in the Entropy of the system will be exactly equal to the Entropy decrease of the surroundings. Thus, the net change in the Entropy of the system and its surrounding will be zero. But in an irreversible process in an isolated system (for ...


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As far as I know, the expansion of the universe contributes into creating more and more microstates. This is almost equivalent to saying that entropy increases (because $S = k_B$ln$(\Omega)$). We cannot be sure that the law of entropy applies to the whole universe (There is debate if the universe is a closed system or not, if its infinite or finite, etc..) ...


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By definition a reversible adiabatic system has $dQ = 0$. We also know the following from the Clausius Theorem : $dS = \frac{dQ}{T}$ Then it is easy to see that there can be no change in entropy. Note that irreversible adiabatic systems CAN see a change in entropy because in that case the above equation is no longer an equality but an inequality : $dS ...


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It is common to hear in cosmology that the entropy of the universe is adiabatic (constant) at late times. In the standard model of cosmology, $\Lambda CDM$, the universe is dominated at late times by the cosmological constant that causes exponential expansion of the universe. During this epoch, the formation of new structure is limited by exponential decay, ...


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Yes and No Yes part If you think the whole Universe as a closed system , then the entropy must be constant. How come ??? According to Quantum mechanics , the evolution of a closed system is unitary. The unitarity forces us to believe that the whole universe can be thought of as a reversible computer and so a big fine quantum computer. Now since the whole ...



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