I am happy to be patient to be availed your great understanding at your convenience to criticize my poor layman's understanding.
I, poorly read, am unfamiliar with other models of dark matter. However, any of them seem unnecessary given my understanding that spacetime, which includes all times including those we perceive as past and future times, is affected by mass such that it warps.
Regarding the arrow of time, I reckon that applies to our perception of it, rather than the actual nature of it, because time does not exist. Spacetime exists, and, as such, I see no possibility that it only exists in one 'direction', but rather is a unitary whole. We may not be able to perceive that whole, but that whole exists nonetheless, and we can observe that space is not unidirectional in any way, so there is, IMHO, essentially proof that time cannot, since spacetime is one thing.
It is not possible for us to perceive the future. However, we can conceive of it, at least estimate it. IMHO the future is an artifact of our means of perceiving, not the nature of reality. I conceive of reality as a gestalt, a crystalline clockwork that incorporates such beginning and end in it's whole.
I cannot understand how spacetime could exist otherwise. Would spacetime somehow erupt from probability in planckian quanta from the vacuum? How could the totality of the universe be inextant and only become extant per time, when time does not exist? It is our perception that is limited, not the universe, IMHO.
Thanks!
Please don’t worry. There are so many models available that is is hard to be up-to-date. I am definitely not myself fully up-to-date, although I know the big classes of models available (which is different from knowing all models taken individually).
The issue I have with the above statement is that it has problems with various known laws of physics. For instance, causality would be deeply broken and thermodynamics too. It is all connected to the arrow of time (see below). There is a one-way observed direction of time, at least at the macroscopic level. How would your understanding deal with this? This is unclear to me.
This is another thing that is unclear to me. Time exists, and the same manner as space exists. They are both components of spacetime. The fact that we can unify them in a more general concept does not mean the individual concepts are incorrect or cannot be taken individually to solve certain problems.
Finally, predicting the future is different from having the future impacting the present. This is where causality hits us. As said above, this is where I don't understand your reasoning and where I would need more clarifications.
Actually, you are not the only one who cannot understand this. This is a good question and hopefully we will see an answer, at least some day.
Have a nice week-end!