In this post, I am going to think of the universe as a whole. I am furthermore going to assume the truth of the standard model of cosmology, which says that the universe is expanding as time progresses.
Now, at every point in time, the universe has an average mass-energy density, which is equivalent to saying that it has an average gravitational potential.
By General Relativity, we know that clocks move slower in fields of higher gravitational potential.
If we go backwards in time, the universe gets progressively smaller, thereby consisting of a progressively higher average gravitational potential. It follows that the average clock in the universe will get progressively slower.
As we approach the moment of the singularity, we can see that the rate of the average clock will approach zero.
As we finally hit the singularity, clock rates become infinitely slow, meaning that the universe has truly existed forever, and the universe could not have had a beginning.
The universe is therefore eternal, and the concept of the big bang is null and void.
Clocks move slower in a region of high gravitational potential relative to those without. But time doesn’t slow down for anything in any absolute sense. If you are in a region of high gravity, physics continues.
Right, time slows down in a relative sense. Relative to the average clock in the universe right now, the average clock in the universe in the past was moving slower. According to our present clocks, we say that the universe is ~14 billion years old. My point is that this estimate is far too low. Relative purely to our current reckoning of time, the universe is much closer to ~infinity years old.
But absolute 0 is just a conceptual hypothesis. It’s equally possible, that the big bang occurs without reaching this absolute. The so called Swarzchild horizon in black holes, is supposed to be the hypothetical limit of black holes. Previously, the thinking was, that as matter approached and went through this limit, it was sucked into this black hole. This is no longer the accepted version matter approaching this limit is thrown back from the black hole without going through it. The black whole in the center of the galaxy behaves the same way. So who is to say, whether a super black hole in the center of the universe, likewise never compresses the universe into a total singularity, but at the critical stage of compression, doesn’t merely explode it? Hypothetical eternity at absolute 0 time, maybe only an abstraction. At the maximum limit, it may get immeasurably close to timelessness. This is science. But can the hypothetical be really an underlying principle?
You can say that if you want. However, the ideal clocks in the Robertson-Walker metric, one of the easiest metric in which to write the standard cosmological model and the one used to represent the “age of the universe”, are the same throughout the history of the universe and they just happen to all be in sync in every ideal galaxy. That is, one can track a clock from then to now and it’s the same clock, sitting in the same physical system, doing the same stuff in the sense of going through physical events over time.
Just like if we stick with a clock falling into a high gravity area, that clock doesn’t slow down, so to if we track any clock backwards and we stick with it, the clock itself doesn’t speed up or slow down. That’s what it means to be an ideal clock.
So there is no difference in the running time of an ideal clock now and in the past. Nor in the RW metric is there a difference between a clock in an ideal galaxy and another ideal galaxy.
Many modern astrophysics believe that BB was just a local phenomenon, but we are a part of a greater universe, therefore there are no paradox in itself, nor that BB would break any laws, as mentioned before, time can change locally without being a paradox elsewhere.
