Can causality and symmetry teach us anything about cosmology?

[padren]

Wouldn't up and down be comparable to 'width'' date=' left and right comparable to 'length', and back and forth be comparable to 'breadth' or 'depth'?

 

aguy2[/quote']

 

Essentially yes. If you want to label what each dimension is for measuring, up/down would best match height. They are all interchangable.

 

Up/down/left/right/forward/back/future/past are directions based on a subjective "center point" or point of reference.

 

Width/height/depth/breadth/length etc are all just measures of distance. Time is a bit wierd because you can't measure 8 meters of time as you can with x,y,z, but you can certianly measure it based on the count of repetition in causal effects with constant freqencies (such as the atomic clock).

 

 

Is there any research into the nature of time that would give light on if its fundamentally different than x,y,z or if its a matter of our own perception systems resulting in a very fixed point of view?

[aguy2]

Past present and future are not dimensions time has, they are two directions and a point along its axis.

 

How can we presume that the past, present, and future lie along a single axis when all the information we have available to us comes exclusively from the past? Information can tell us how things were, not how things are, and certainly not how things are going to be. Admittedly, a lone, lineal, temporal dimension seems to be intuitively logical, but doesn't much of what little physics tells us about the temporal dimension(s) seem counter-intuitive?

 

aguy2