Heat death === no remaining thermodynamic free energy. The universe is all one temperature, though theories vary widely on what this temperature might be. At h

Heat death === no remaining thermodynamic free energy. The universe is all one temperature, though theories vary widely on what this temperature might be. At high temperatures crystals vaporize, absorbing heat. At low temperatures, gases sublimate onto the crystal, releasing heat. Either way, if you have crystals, the universe hasn't completed its heat death yet because you could use the crystal to do work.