Just food for thought.
As human beings, we naturally assume that time is separate from matter and goes on forever in both directions. We base this assumption on the observation that matter has moved and changed since the big bang, and for it to have moved there would need to be time. But what about before the big bang? Did time exist then? Most people assume that time has always existed before the big bang and it was only a random factor that the big bang happened when it did.
But not necessarily.
According to Einstein's Theory of Relativity, we know that time and space are relative of each other. And while they can be measured separately, we should never loose sight of the relationship between the two. What does this have to with time before the big bang? Well the theory also states that time will speed up near areas with lots gravity, and time will slow down in emptier places with little gravity.
What does that mean for us? That means that if we're in a place with absolutely no gravity, then likewise, there should be no time either (i.e. before the big bang). And it makes sense too. This way of approaching the Universe allows us to understand why it started when it did and not trillions of years before or a single second after. Time exists only relative of matter, and matter only relative of time. There's no universal time line for events to sit on. Things only happen in relative time to one other. The big bang happened when it did because time didn't exist until after it happened.
To go back to the main question, "Is time universal or does it exist only in the presence of matter?" We can now say that we know why it only exists relative of matter. We don't need to rely on supernatural answers for a very a natural question.
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Spacetime may not even be fundamental.