Nature of Energy

[Alex K]

It's not a question of time intervals becoming short (whatever that should mean). No need to go to the big bang, you can, at least hypothetically, ask the question how e.g. a particle reaction today proceeds between time "t" and time "t + planck time". If the difference in time you study is small enough, you run into this conceptual problem. For the description of everyday physics, the detailed goings-on at such short time steps might not be relevant because they average out, but since you ask the question about the *fundamental* nature of energy, you require us to consider nature to arbitrary, nay, infinite, precision and see whether we can still describe it - that's what the demand for a truly fundamental picture entails.

At the LHC, we are trying to move closer towards this unattainable goal: using higher and higher energy collisions, one can probe the laws of nature at ever shorter time scales because the collision energy is directly proportional to the frequency of the particle waves. However, the LHC does not reach near Energies where Planck time processes can be resolved. That's why it is a hypothetical endeavour for now to think about the breakdown of the concept of a continuous timeline.

Still, if you want to theoretically describe ever smaller steps in the evolution of a physical system, you run up against this barrier of Planck-Time steps, and that tells you that the *fundamental* description of nature might be more complicated than just having time flow continuously.

Okay, I cannot understand most of this, but I'm getting a glimpse of what I'm asking about.  Does what you say here also imply that the supposed linear nature of time also breaks down at very short time intervals?  (Does it make sense to ask if a segment of time is infinitely divisible?)

I think it makes sense, and the linear nature of time might indeed break down. People who deal with this problem explicitely are working in Loop Quantum Gravity research. They construct spacetime as basically a network of discrete nodes giving rise to the famous "quantum foam" concept of spacetime. They have a real hard time properly defining what time is!

Maybe it helps to look at something familiar to get the general idea. A water wave is a continuous thing if you look at it at human scales, characterized by the distance between its troughs and peaks, and how high the peaks are, but if you look closer and closer, you find that it is made up of discrete atoms binding together in complicated ways, evaporating, mixing, etc. The fundamental description of a water wave when you zoom into it far enough suddenly involves very different ideas than the concepts you use to describe water from a macroscopic human perspective. The same could happen with time when we zoom in to look what happens in super short time steps.