# Does energy conservation take into account the dimension of time?

We know that there are only 3 spacial dimensions because if we light a light bulb, we are able to measure the energy at any point in the 3 spacial dimensions and we can see that no energy is leaking into a 4th spacial dimension. Can the same thing be said for the time dimension? If we flash a flash bulb, can we measure the dwindling of energy over time in the same way? Is all the energy accounted for? Or is some of it leaking into another time direction?

• I am just now reading Rovelli's "The Order of Time". On page 134, he says "One (variable) does not vary: the total amount of energy in an isolated system. ... knowing what the energy of a system may be... is the same as knowing how time flows because the equations of evolution in time follow from the form of it's energy." I believe that this helps to answer my question above, but I'm still going to have to figure out how something that does not vary (total energy in a system) can have any relation to time. Intuitively it seems the exact opposite. Oct 17 '18 at 17:09