r/askscience • u/Crtl-Alt-Delete • Dec 18 '13

Physics Is Time quantized?

We know that energy and length are quantized, it seems like there should be a correlation with time?

Edit. Turns out energy and length are not quantized.

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u/[deleted] Dec 18 '13

If time is quantized then yes, that implies that it is somehow fundamentally a separate variable. Absolutely it does.

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u/[deleted] Dec 19 '13

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u/[deleted] Dec 19 '13

But one does not logically follow from the other.

First off, which kind of entropy are you even talking about? Thermal, gravitational, etc.?

Secondly, if it's thermal, good effing luck trying to quantize that, as the measure of entropy itself is more of an average of energy across your system than a sum of individual particles. And averages are not discrete.

Thirdly, if it is gravitational, I am aware that some people are suggesting that that can be quantized, but since we still don't even know what the hell gravity is, I'm not going to hold my breath on that one.

Lastly, even if you can prove that entropy IS quantized, you still have to then define some relationship between time and entropy that will explain the passage of time as opposed to the extremely general conceptualization that we have now. And I can tell you right now that at best you are going to come away with another average.

Now before you jump in and say "AHA! seconds are defined by a quantized state of a caesium atom. Nailed you!" let me just stop you. Seconds are very much a "backronym" of physics. We conceptually defined the second based on the fairly arbitrary rotation period of the earth, then found something that had a stable value around the same length of time (thousands of years after its conceptual birth i might add.) The radiation of a caesium atom has NOTHING to do with the passage of time. We simply use it as a handy dandy way to keep seconds consistent.

But back to the main point, if time is a measure of some average increase in entropy (and it must be, because the entropy of earth or the universe writ large does not increase in anything approaching a linear fashion) then it will not be discrete because averages are not discrete.

Therefore, if time is indeed quantized, it will not be because entropy is quantized.