I spotted this science post from Darksyde at Kos the other day but it wasn't till about 3AM today that it finally started to work.
SC: Dark energy is completely different -- it's a certain amount of energy density inherent in space itself. Every cubic centimeter of space contains a fixed and immutable amount of dark energy, even if it's completely empty! The dark energy doesn't cluster into galaxies like dark matter, nor does it dilute away as the universe expands. Again, we have multiple independent lines of evidence in favor of this surprising idea -- from precision measurements of the expansion of the universe, to the evolution of large-scale structure, to the overall curvature of space itself. What the dark energy really is, and why it comes in the amount it does, remain a mystery; but there is plenty of evidence that it really is there.
Enlarge Illustration--Recent observations indicate the presence of mysterious Dark Energy which is accelerating the rate at which the universe expands. if this process continues unabated, it could result in The Big Rip: Time and Space, down to the scale of individual atoms, will literally explode.
Now, what keeps trundling through my grey matter is this. If the universe expands at an ever increasing rate until it tears itself apart at a subatomic level, the energy level of the universe at the very last instant is going to be about whatever it was at the beginning.
But the Third law says "The entropy of an isolated system not at equilibrium will tend to increase over time, approaching a maximum value." So how does that apply to a Universe where the predominant force is dark energy that ends up driving everything, even atoms, apart at speeds beyond the speed of light?