What's the medium?

[paradox42]

Yes, plausible. But there are a couple of things to note -

1)This would nto be an "event" as we think of them. It is not along the dimension we call "time". So, it isn't that it happened "before" the big bang. It would be just as correct to say it happened to the left of the big bang.

Yes, quite true. Clearly, events in another spacetime are meaningless from our perspective, and not properly definable as "events" in the strictest sense of the term. Quite fun to think about though, at least for me. I do love pushing my brain into the higher dimensions, and dealing with concepts like orthagonal time.

2)Aside from this sort of accounting for the Big Bang, there is no cause to consider that our universe is ebedded in a larger space. There's no evidence of which I'm aware that we interact with such a space, and quite a few reasons to think that we don't. Interactions through larger spaces are a real headache in terms of causality. Occam's Razor applies - you don't go invoking spaces that are convenient, but which aren't actually necessary.

IMHO the whole concept of 'causality' as such is flawed, because the modern theories don't have an embedded 'arrow of time.' They're time-symmetric, and as you must be well aware (given where you work) there are a lot of experiments going on recently which are looking for some sort of symmetry violation to try to explain the arrow, none of which have given more than vague hints as yet (and certainly not enough to base broad statements on).

Time, to put it bluntly, doesn't move; it's a direction in its own right. So the notion that one 'event' (however you define that) can force another one to happen later in time seems just... wrong. It seems to imply a movement that isn't actually there, and even if that's the way our brains are constructed to think about the universe we live in, nothing says our brains are preceiving the whole truth (in fact, quite a few experiments have demonstrated that they don't). Causality as a notion has yet to come to grips with the lack of an arrow in the basic laws of physics- and that, to me, means that it needs to adapt.

The difficulty, of course, is trying to envision what a science without causality could be like.

 

[Hypersmurf]

BRAAAAA-ANES!

-Hyp.

 

[MavrickWeirdo]

2)Aside from this sort of accounting for the Big Bang, there is no cause to consider that our universe is ebedded in a larger space. There's no evidence of which I'm aware that we interact with such a space, and quite a few reasons to think that we don't.

It depends how you explain the “acceleration” of the expansion of the universe. It is possible that it is evidence that we interact with such a space. I believe it is still considered an “unsolved” phenomenon (i.e. there I no "likely" theories) therefore Occam's Razor has nothing to shave there.

 

[MavrickWeirdo]

Time, to put it bluntly, doesn't move; it's a direction in its own right. So the notion that one 'event' (however you define that) can force another one to happen later in time seems just... wrong. It seems to imply a movement that isn't actually there, and even if that's the way our brains are constructed to think about the universe we live in, nothing says our brains are preceiving the whole truth (in fact, quite a few experiments have demonstrated that they don't). Causality as a notion has yet to come to grips with the lack of an arrow in the basic laws of physics- and that, to me, means that it needs to adapt.

The difficulty, of course, is trying to envision what a science without causality could be like.

You are assuming time is a "full" brane, rather than "half a brane"

The mathimatical definition of a Line (not a "line segment") is a series points in a straight path extending beyond the points in both directions infinitely.

a ray is part of a line starting at a particular point and extending infinitely in one direction.

It seems to me a ray would therefore be half a line. (Infinity in 1 direction being half of infinity in 2 directions.)

I am suggesting that the brane of time is a "ray" which only extends in one direction (the future) which is why I said earlier our spacetime is 3.5 branes.

 

[the Jester]

I am suggesting that the brane of time is a "ray" which only extends in one direction (the future) which is why I said earlier our spacetime is 3.5 branes.

Wow, that's a fantastic image.

 

[MavrickWeirdo]

Wow, that's a fantastic image.

That's what happens when you teach math to art students.

 

[elforcelf]

Flumphs created them!

 

[RedWick]

I don't believe in time. Just a perpetual now which likes to arrange itself to make it seem to observers within it like time really exists. The thing I keep running circles around in my mind is defining exactly what an observer is. Keep coming back to thoughts about religion/spirituality and information leak. Burgeoning awareness and a growing informational depth/capacity due to the expansion of the universe or somesuch.

None of that actually helps in determining what branes are though...

*chuckles*

 

[Umbran]

Yes, quite true. Clearly, events in another spacetime are meaningless from our perspective, and not properly definable as "events" in the strictest sense of the term. Quite fun to think about though, at least for me. I do love pushing my brain into the higher dimensions, and dealing with concepts like orthagonal time.

To my way of thinking, it is generally useless to think of it as "orthogonal time", in that it does not pass the way time does. Setting the math aside for a moment - time is special because we perceive it differently than we do other dimensions. It is not useful to speak of other dimensions as akin to time unless they share that characteristic.

IMHO the whole concept of 'causality' as such is flawed, because the modern theories don't have an embedded 'arrow of time.' They're time-symmetric, and as you must be well aware

I don't have time at the moment to discuss symmetries in full - one could write textbooks on the subject. However, I can say that not everything in our universe really is time-symmetric, especially on the quantum level.

But, even staying away from particle physics - while it is true that Netwonian mechanics is time-symmetric, thermodynamics clearly isn't. Somewhere between dealing with individual discrete objects and working with large collections, time symmetry is lost. We don't know why, but it is true nonetheless. We can show that the order of events does matter, so causality is not an illusion.

Time, to put it bluntly, doesn't move; it's a direction in its own right. So the notion that one 'event' (however you define that) can force another one to happen later in time seems just... wrong. It seems to imply a movement that isn't actually there

Whether you want to say time is moving forward, or we are moving forward in time, it amounts to the same thing. You can even consider a sort of Newtonian description - objects in motion tend to stay in motion. If everything in the Universe has been set in motion along the time direction at a particular speed, we have motion through time. If there are no "forces" that act in the temporal direction, we have a temporal arrow of a sort.

The difficulty, of course, is trying to envision what a science without causality could be like.

That's not difficult - Newton's laws are such a science. Anything that doesn't include reference to time in a non-reversible fashion is such. The science isn't the problem - the philosophy that comes from it is the hard bit.

 

[Umbran]

I believe it is still considered an “unsolved” phenomenon (i.e. there I no "likely" theories) therefore Occam's Razor has nothing to shave there.

Well, there is no one theory that everyone accepts and is well tested and all, no. But there are several candidates. Proper use of Einstein's cosmological constant, for example, can produce inflationary effects.