Why is it that when we sleep we have no concept of time?

Question

Why is it that we go to sleep and the next thing we know we are awake again and we have no concept of time in between that?

Answer 1

because time is of no importance during sleep and there are no relations to time similar to those when being awake.

when awake, almost everything you do or experience is related to time. when you sleep, your subconscious is the only "thing" that keeps track of, say, how long you sleep. if you wake up after three hours because of a loud noise, you might not know what time it is or how long you have slept, but if you know your body a little, you will notice that you are still tired and you might even be able to estimate how much more sleep you need.

apart from that, time is used for coding and other processes in the brain, and coding is again used to coordinate things. when asleep, there is nothing to do or react upon. the brain stops working (well, not completely) and thus the concept of time also is "paused".