What is the "Force" (DE?) that is causing that acceleration? That's what intrigues me. And is there an inverse gravity field existent in intergalactic space, as suggested may be possible now that we have observed a "Pioneer anomaly"?
I believe strongly it is the Gravitational Constant proposed by Einstein at a time when it was thought the Universe was constant and not accelerating or moving. Einstein had put the entire equation Over G the Gravitational Constant in order to balance out the universe and keep it from collapsing in upon itself. The genius of this is that we are not living in a static/constant universe, we are in an expanding universe. The Gravitational Constant functions exactly the same in this type of environment and is very mis-understood.
Gravity = the warping of space/time around mass.
Gravitational Constant = the inverse pushing force which may actually be stronger the further away it is, like Gravity is stronger the closer you are to a Gravitational source, the gravitational constant tells us we are also being pushed, a force is being exerted on us, by all those far away galaxies.
anyway you throw the gravitational constant into our equations of an expanding universe and there is no need for Dark Matter.
Also an important note, the Universe, whether expanding forever or collapsing into the Big Crunch before another Big Bang, will not go on forever. Entropy, release of heat/radiation will always be continually eating away at the universe and so even a Big Crunch/Big Bang would not be as large the second time around. Eventually there wouldn't be enough matter to pull the universe back to its crunch and it would expand forever, eventually running out of fuel for Stars and becoming a very dark/black uninhabitable place. Kinda sounds like hell to me.
so yes imho there is an "inverse gravity field existent in intergalactic space" as described initially by Einstein and it would account for the acceleration in the universe. Will this ever be a fact? Well until someone gets me a time machine and a UFO or something, we won't be doing anything but debating based on what we see in our small corner of the universe.