"Hey, it's time again."
"Five more minutes."
"No, boss. Now. Wake up."
"I'm old, let me sleep. You're a cat, you should understand the importance of a solid 14 hours a day."
"Last one, I promise."
"Sure. Until next time. Do you have any idea how much hate mail I get?"
"It's good for your blood pressure. Now go."
A final problem:
Recent observations have indicated that the expansion rate of the universe is actually increasing, invalidating numerous previous assumptions and putting the theory of Quintessence (Ether) back into play. This problem has revitalized superstring theory (previously dismissed in the early 1970s in favor of Quantum chromodynamics) and bringing Maxwell's unification of electricity, magnetism, and light back to the fore of discussion.
At the root of the entire discussion is the blind assumption that Einstein's unified space-time continuum is correct. The sticking point is and always has been gravity.
So, let me offer a different theory altogether. It increasingly looks like Maxwell was right (I'd say it's just about a done deal at this point, as much as science can close a deal. Remember, science as a tool cannot prove anything. It only disproves things until we are left with a sufficiently limited scope of functioning theories.) It also is very possible that Einstein's general relativity is wrong and that Lorentzian Relativity (LR) is right. Now factor in the idea from quantum mechanics that there can be additional dimensions. (Last time I looked, we were up to a minimum of four and a maximum of eleven depending on which formula you need to make your math work for string theory. This is another area more rightly classified as pre-science than true science. It's early in the game still.)
LR allows faster-than-light propagation (a phenomenon already demonstrated experimentally back in about 2005) and it assumes time is not, in fact, inextricably bound with space into a single continuum. Time exists independently of space and therefore can, within certain boundaries, have an absolute value. (Remember, Einstein's theories of specific and general relativity are difference theories and Einstein himself proposed a universal constant.)
(I would like to side track here for a moment to observe that the clocks within all orbital GPS satellites are synchronized and have evidenced no time dilation despite years of different speeds. This should be impossible under general relativity and yet, as far as I know, this phenomenon has never been properly addressed.)
So, taking FTL propagation and space-time separation from LR and multiple dimensions from quantum mechanics and applying this against the observed gravimetric quandaries of Dark Matter, I ask, why not a second dimension of TIME rather than space. There has never been any reason to assume that extra dimensions must be spatial and the idea comes a lot closer to explaining the observed gravimetric data than making up an entire host of random magically invisible particles. What if the gravimetric effects that we cannot explain currently are because the force of gravity extends into a second temporal dimension? Mass (or more precisely masses) out of temporal phase with our universe would fit all the criteria of Dark Matter with fewer complications. It may very well be that gravity turns out to be the unifying universal force instead of the half-ignored, despised step-child that modern physics treats it as. Do I think my idea is the one true and perfect answer? Absolutely not. I do, however, think it deserves equal consideration with the other theories that have been presented and I also think that our blind subservience to the theory of general relativity has gone on long enough. Rather than build new castles in the air, it is time to re-examine the foundation beneath. Just as Einstein assaulted the orthodoxy of Newtonian physics, it is legitimate to question in turn the orthodoxy of Einstein.
Ah but what do I know? I'm just a crazy old man.