Entropy refers to the amount of disorder within any isolated system, or more precisely a measure of the unavailable energy in a isolated thermodynamic system. This refers back to the Laws of Thermodynamics, which state that the overall entropy of the universe is always increasing and can only be constant if all processes are reversible. Isolated systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy.
If matter is converted into energy in a simple line ----->
but the energy is converted back into matter with a squiggly line ~~~~~>
then entropy within the isolated system was increased by the squiggly line as it took more 'work' to create the matter (and thus increase the amount of unavailable energy), though in total, the amount of absolute energy within the system never decreases per conservation laws. Lost energy becomes 'unavailable', but not 'erased'.
ΔStotal = ΔSsys + ΔSsurr
if ΔS > 0, the process is irreversible and spontaneous
if ΔS = 0, the process is stable and based upon equilibrium, but reversible until > 0
if ΔS < 0, the process is impossible and must be reversing time to occur, or have an outside source of energy being supplied, however this still increases total discrete entropy in the universe
|This article is an attempt at shortly describing real science which can be sourced and referenced in real research. While it is difficult for me to accurately describe complex topics, especially with my limited background in physics of all kinds, an attempt is made to simplify it enough and both further my own understanding via repetition and correction. Please excuse any errors in syntax or bias, typically I am unaware of every possible interpretation of many of the more argued subjects and tend towards ones I have studied more, rather than any explicit following of it.