Why time dilation?

[Qfwfq]

Which philosophical difficulties? I really can't see any.

 

I see far more difficulties with the notion that space and time might be discreet. I can't easily see space being discreet without it having a grid-like structure implying some directions not being equivalent to others. There is no evidence against spatial isotropy, to the contrary it is a fundamental axiom of all modern physics. I don't believe it is the right way to interpret Planck length and time.

[DrProctopus]

If something is infinitely divisible, it can contain an infinite amount of information.

 

If spacetime is the framework of reality, then, if spacetime is infinitely divisible then reality should be infinitely divisible.

 

Think of it this way - matter and energy are discreet. Why is this the case? If matter and energy are forms of information, that information has to be encoded onto something - that something being spacetime.

 

If spacetime were infinitely divisible, it would not lead to discreet, same-sized, basic particles.

 

I am not expressing myself properly here - trying to translate visual images into words - so my apologies for being inexact.

 

 

another way to think of it...

 

A hydrogen atom is always the same size as any other hydrogen atom (ignoring charged particles and any other unusual manifestations - just a plain ol' hydrogen atom)

 

Why is this the case? The answer that seems apparent to me, is that spacetime is granular, and thus always encodes information in the same way - meaning the fundamental particles always manifest in a consistent fashion.

 

 

 

 

As for a grid-like structure - well, I dunno. I can envision a number of different designs. You could be onto something, though. One way of trying to figure out the fundamental shape (or abstract shape, since the concept of shape might not be so meaningful at that scale) of a spacetime moment would be to figure out a shape that results in an equal rate of the transfer of information in all directions.

 

I am not even sure that thinking of a spacetime moment as a simple 3-D structure is the right way to envision it. It might be better to think of it in information-processing terms. Like, in an object-oriented programming sense, you could think of a spacetime moment as an object that processes information, has a number of properties that define things such as gravity, space, space curviture, etc... I would be wary of taking that analogy too far, but it might be useful.

[Qfwfq]

If spacetime were infinitely divisible, it would not lead to discreet, same-sized, basic particles.

The standard model does lead to discrete, same-sized, basic particles, yet this doesn't require discrete space and time.

[DrProctopus]

In the standard model, what is spacetime? What role does it play in determining particles and waves?

[Qfwfq]

In the standard model, what is spacetime?

The same as what it is in all of particle physics and in relativistic quantum field theory. It does't play any special role in determining particles and waves, there simply isn't a need for it to be discretized in the SM.

 

Apart from this, there isn't much point in finding a mechanism for time dilatation. Actually it isn't even something that "happens to" time, as may suggest the way it's commonly called. It is really just a change of coordinates, observers that have different velocities have different proper times; each sees the proper times of the others differently.

[DrProctopus]

Apart from this, there isn't much point in finding a mechanism for time dilatation.

 

Um... well - we won't really know until we get there will we? I mean, surely physics is about determining the why behind things, not just predicting what will happen during certain events?

 

 

Besides, if we figure out the underlying mechanism, we might find useful things to do with it.

 

 

 

It does't play any special role in determining particles and waves,

So, why are protons always the same size, the same charge, etc...?

[Qfwfq]

Um... well - we won't really know until we get there will we?

Um, I think you missed my point about what it is and what it isn't.

 

Time doesn't "dilate", it's just that my proper time isn't the same as yours and yours isn't the same as mine. Time dilatation is but a figure of speach to say that each of us sees the other's as being "longer". When your twin brother returns from his odyssey and isn't as old as you are, it's very much akin to the fact that a winding curvy path is longer than the straight one between the same two points.

 

So, why are protons always the same size, the same charge, etc...?

The standard model offers an explanation, I only said it isn't space-time that plays a role, not of the type you are after. The geometry and the number of spatial dimensions are relevant but not any discrete nature of space and time.