Nature of Energy

[Alex K]

If time stops to be a continuous thing when looking closely enough because it becomes fuzzy or discrete at short enough time intervals, it will become difficult to even find a fundamental definition of what Energy is, and the concept of Energy might just be describing an emergent property of physical systems (like air pressure or temperature) that is not really a fundamental property of stuff but instead something that only appears when looking at large averages of particles or, in this case, many Planck time intervals or what have you.

Are there any examples of when time intervals may become that short besides perhaps very near the initial event of the Big Bang?

It's not a question of time intervals becoming short (whatever that should mean), it's a question of how short time intervals we want to describe with our theories. 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 between 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 at 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.