sol invictus
Philosopher
- Joined
- Oct 21, 2007
- Messages
- 8,613
I don't think it necessarily has to be at the center of the distribution, it simply has to be somewhere in the acceleration stage.
Solar wind particles do continue to drift further and further apart from their solar wind neighbors (particles that left the surface at roughly the same time) over time. Some particles might have a similar trajectory, but over some long period of time, any deviation in trajectories leads to a ever growing distance between particles. As long as the acceleration process is constant, even particle ahead of us are moving faster and away from us, and particles that left later are moving slower and getting further apart. Everything visible would still have a redshift from our vantage point.
That doesn't work for several reasons that ben covered nicely. But it also doesn't work on a more basic level. What exactly is this cosmic analogue of the solar wind? It can't be literally a wind, because the energy required to accelerate galaxy clusters is so gargantuan that the wind would have to be ridiculously dense and powerful. It can't be an EM field for reasons thoroughly explained many times.
It has to be some kind of force field, something that's weak on short scales but can build up over very long times and distances and exert enormous force on large structures. The only force we know of that has those properties is gravity, and the only models (that I know of) that can explain the cosmic acceleration with gravity are spherically symmetric models or models with dark energy. So you're back to square one.