The order of a physical system measures its degrees of freedom, where high order implies fewer internal choices. In physics, a system’s disorder is called its entropy. The second law of thermodynamics states that entropy always increases over time for a closed system, so if the physical universe is all there is, it’s expected end-state is one of maximal disorder. In this dismal vision, the universe will end in a thermal equilibrium where everything disperses to maybe one atom per cubic light year. After this big freeze, it is expected that nothing will change, forever! This section suggests that the universe is evolving up to create order even as it is winding down to a big freeze.
QR5.6.1. What is Potential Energy?
QR5.6.2. The Universal Conservation
QR5.6.3. Disorder is Probable
QR5.6.4. Order Happens
QR5.6.5. The Law of Evolution
QR5.6.6. How Will The Universe End?