My morning coffee reminds me of my predicament. It sits there, on my desk, freshly percolated, and still steaming. But an hour goes by, and its temperature returns to thermodynamic equilibrium with the rest of the room.
The last few sips, at this unsavoury temperature, retell the story of my own situation in an entropic universe. My coffee, like everything, moves only in one direction: from hot to cold.
What made my coffee hot in the first place? The energy that excited the molecular state of my mug — whether extracted from a coal mine or harvested from the solar radiation with photovoltaic cells – was a unique occurrence. Never again will that lump of coal be burned. Never again will that wave of radiation strike the Earth. Never again will that gust of wind push a turbine. Just as the coal mine cannot be replenished, the sun cannot be refuelled. From the vantage point of thermodynamics, the notion of truly renewable energy is an odd bit of make-believe. Entropy says that nothing can possibly be renewable forever. Even the gases that give rise to new stars must, eventually, run out. Therefore, the particular sequence of chemical interactions used to raise the temperature of my coffee will never be repeated: this instance of energy is a singularity.
Thus, the law of entropy states that everything moves towards disorder. The energy that was harnessed to heat my coffee has been distributed out into the world, now lost in chaotic non-usefulness. It was transferred to my hand, the air, and the desk upon which it was sitting. It irreversibly rushed towards uniformity with everything around it. Like the combustion that released it, it too is now gone. Irrecoverable.
Like the heat it once possessed, the structural integrity of my mug itself is no less susceptible to entropy. Just as rocks, mountains, and continents erode, it too will disintegrate. Like energy, matter is destined to scatter. Everything falls apart eventually, but systems — like our incredibly evolved metabolisms, for instance — give us a shot at life.