The heat death of the universe (also known as the Big Chill or Big Freeze) is a theory on the ultimate fate of the universe, which suggests the universe would evolve to a state of no thermodynamic free energy and would therefore be unable to sustain processes that increase entropy. Heat death does not imply any particular absolute temperature; it only requires that temperature differences or other processes may no longer be exploited to perform work. In the language of physics, this is when the universe reaches thermodynamic equilibrium (maximum entropy). Don't worry! Heat Death may not happened. If it finally happened, it will be at least `10^100` years later.