Why can't anything reach absolute zero?
Nothing reaches absolute zero because each cooling step takes away a fraction of what is left, and a fraction never finishes the job. A repair step redraws a system's unsettled part from settled odds that give every arrangement some positive share, so a possibility with weight before a step keeps weight after it, and finitely many steps extinguish nothing. Walther Nernst told the Göttingen Academy in 1905 that a cooling system's entropy approaches a floor set by how many arrangements it has at its lowest energy. Ice keeps a floor above zero, because its hydrogens can sit in many arrangements without breaking the local rule. Linus Pauling counted 0.805 calories per degree per mole, and William Giauque and J. W. Stout measured 0.82. A sodium gas at MIT reached 450 trillionths of a degree in 2003.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read chapter 23: Why Does Writing Something Down Cost Heat?watch a universe make its own particles