"If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations—then so much the worse for Maxwell's equations. If it is found to be contradicted by observation—well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation."
NOTHING in the intervening century has given any reason to doubt Eddington's dictum.
The Four Laws of Thermodynamics are, as nearly as we know, absolute and infallible.
The Zeroth law of thermodynamics states that if two bodies are individually in equilibrium with a separate third body, then the first two bodies are also in thermal equilibrium with each other.
Consequence: If system A is in thermal equilibrium with system C and system B is also in equilibrium with system C, then system A and B are also in thermal equilibrium.
First law of thermodynamics, also known as the law of conservation of energy, states that energy can neither be created nor destroyed, but it can be changed from one form to another.
Consequence: It is impossible to build a machine that produces energy ex nihilo.
Second law of thermodynamics states that the entropy in an isolated system always increases. Any isolated system spontaneously evolves towards thermal equilibrium—the state of maximum entropy of the system. The entropy of the universe (or any isolated system) only increases and never decreases.
Consequence: It is impossible to build a (perpetual motion) machine that converts ambient heat into useful work without emitting some heat into a heat sink at lower temperature.
Third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero. The entropy of a pure crystalline substance (perfect order) at absolute zero temperature is zero. This statement holds true if the perfect crystal has only one state with minimum energy.
Consequence: It is absolutely impossible to reach the temperature of Absolute Zero.
Source: https://byjus.com/physics/thermodynamics/
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