Temperature and Time.

[igotrhythm]

Originally Posted by devonin

If such a thing were to happen, we couldn't think anything about it anyway. If the temperature of the universe were to somehow instantaneously reach absolute zero (And it would have to be both instantaneous and come from some magical impossible outside force [In order for it to happen naturally, my intuition is that we'd need every particle of matter to be infinitely far away from every other particle of matter, which would both take infinite time, and happen long after humanity ceased to exist] in order to actually happen instantaneously)

In such a case, to a magical outside observer who isn't bound by the laws of our universe, everything would appear to be frozen. To anything inside the universe, nothing would appear to be anything, because, well, everything would be frozen, which includes the various chemicals in our brains necessary for thought or awareness.

If things were then to go back to normal, not only would we not notice that anything had happened, from the perspective inside the universe, it would be the true case that nothing had happened. These stops and starts could be happening constantly and we have no way whatsoever to perceive them.

As scary as hell as the bolded portion is, I'd have to agree. I'm not 100% positive on this, but I believe at least one of the famous atomic clocks keeps track of time by using the metric definition of a second as the time it takes for an atom of a certain isotope of cesium to vibrate a certain number of times at a certain temperature.

Now think...if all motion in the universe were to stop (since we are at absolute zero), a second would thus be infinitely long to this magical external observer, but as pointed out, those inside the universe would have no way of perceiving it. We would not be frozen in time, for time itself has stopped in this universe, at least as far as the metric definition of the second (and thus all other measures of time) goes. But I agree, we would not be aware of it; however, this assumes that time continues to march on for the outside observer. It would perceive a snapshot of the universe at the state it was in when the temperature hit absolute zero.

I'm not sure about the stops and starts thing, though. (As long as we're postulating about magical observers that exist outside, and are thus not bound by the laws of, the universe we know...) If our universe were to suddenly go to absolute zero, what, then, would be the force that restores our universe to the state it was in before?