_heretic

So are you saying that all references frames, backwards in time, all converge into one reference frame?

So, in cosmology, is consideration normally given to how we go from this absolute time, at the big bang, to multiple relative times?

Can you confirm that with something peer reviewed? It sounds like something I should be highly dubious about.

So we think we know that time began at the Big Bang. Why isn't there are universal time as a consequence of that?

I am aware that that is the idea. What I am not clear on is that if time does "begin" how can we have all of these various fields forming? It gives the impression that there is a universal time under which these events are unfolding. Expect relativity tells us that can't be the case. To put it loosely, each thing has its own time.

If that's the case, what's time dilation, length contraction and relativity of simultaneity supposed to be?

Thanks for the suggestions, I'll look into them

I, myself, am of the view that the universe has always existed in some form. This abstraction of "absolute nothingness" is useful in as far as being a self-refuting idea.

So Prof Cox is in error it seems. Did your Professor explain the correct understanding of the principle?

Thanks that has made it a little clearer. What I'm still having trouble grasping is how, with a specific origin of time at the Big Bang, there is not one linear universal progression of time that would come out of it.

But this is only with respect to "our" reference frame. There isn't really a 'cosmic timeline'; so how can we say time had a starting point as if to suggest space-time appeared and started ticking away. Yet GR tells us time does not just 'tick-away' in the background. (Note! I'm not rejecting the fact of the Big Bang here).

General relativity tells us that there is no universal time. It all depends on your frame of reference and velocity relative to other things. So how can it be that time "began" at the Big Bang? - which is the conventional viewpoint.

Are there any experiments I would ideally be able to do, say, on my lawn with cheap equipment, to test special relativity?

I see. I didn't grab that paraphrase from a book on quantum gravity, however, it was from his book: The Road to Reality: A Complete Guide to the Laws of the Universe, which is about the standard model of particle physics, general relativity, special relativity and possible TOEs. So, anyway, special relativity has been worked out with QM. What about EPR situations?

Ah, I probably just mixed up that paraphrase then.

Is there any formulations of quantum mechanics out there that are relativistic? i.e. interpretations that take special and/or general relativity into account when describing the behaviour of quanta? As I understand it, traditional QM is not relativistic, time is just sort of "bolted on" and 'ticks away' in the background. I think I recall reading something by Roger Penrose where he said that when relativity is added to the picture at the quantum level, problems arise; something about a particle going its merry way down its own time dimension (?)

I am interested to know how you came across the website, Alexander1304

Excellent, thanks a lot for that Fair enough, but the thing is, do we understand what the QM calculations are telling us?

Thanks.

This is a shame to see that Prof Cox may well just be wrong here. Especially when he repeats the mistake in his book. So, is the Pauli Exclusion Principle at odds with Relativity in anyway?

The Pauli Exclusion Principle says, roughly, that no two atoms are allowed to occupy the same energy states at the same time. The result of this is apparently that every atom must change its energy state in response to every other atom so as to obey this rule. The well known physicist Brian Cox likes to mention this, such as in his book The Quantum Universe: Everything that Can Happen Does Happen, to say that this implies that the energy states of atoms billions of light years away from one another must change their energy states simultaneously in obedience of this rule. In his book, he assures the reader that this does not violate the theories of relativity because information can not be communicated by making use of this and so temporal paradox situations are avoided. However, surely this is not good enough because relativity tells us that there is no universal time, each particle has its own time. So if the Pauli Exclusion Principle really does say what Brian Cox says, should that not imply that the energy states of atoms must also retroactively be changed at all time points so that the rule applies at some arbitrarily chosen time? In addition to this, which frame of reference is supposed to be the preferred one which every atom alters its energy state with respect to?

Does this also include dark energy?

I'm not so sure. Particles only "experience" time when their mass warps spacetime. So surely, in a massless universe, no time would pass? Or does dark energy contribute as mass and therefore there would still be the passage of time?

In a universe which does not contain any mass what-so-ever i.e. every single particle is a massless one, would spacetime actually exist? Or would existence be simply a zero-dimensional point?