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In a comment I read on this page, someone mentions a theory where time is created by moving through and slicing "moments" of a higher dimensional object. For analogy, a 2-D creature living on a plane that moves through a 3-D object may experience the different slices of the 3-D object as "the passage of time" in their 2-D world.

  • Is this idea well developed in physics?
  • Can you share the name of this idea so that I can find it on google?
  • Also, could dark matter play a role in this process?
Qmechanic
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Waveforms
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3 Answers3

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In relativity, and especially in general relativity, time doesn't flow in the sense that we normally think of time flowing. Instead an observer is described by a world line that trace out their path through all the spacetime points $(t, x, y, z)$ that they (momentarily) occupy. For more on this see my answer to Is there a proof of existence of time?.

The world line doesn't change with time. It exists as a static curve with one end at the time the observer came into existence and the other at the time the observer ceases to exist. This has led to the idea of the block universe in which time doesn't flow. The human perception of time flowing is taken to be an artifact of the way the human brain works.

Where this links to your question is that physicists often split up the four dimensional block universe using a technique called foliation. This would be the term to Google if you want to pursue this yourself. Foliating the universe splits it into three dimensional spaces that evolve as we move them through different points on a separate time dimension. This is what Brad Skow is getting at in his article. The flow of time that we humans (think) we perceive is actually just due to moving though successive three dimensional spaces created by the process of foliation.

I should emphasise that while foliation is a perfectly valid and mathematically very useful trick, the question of whether, and if so how, it relates to the flow of time as we humans perceive it is unclear. In fact my own view is that this question may be a good way for philosophers to justify their salaries but is largely pointless for physicists.

John Rennie
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I don't think time is even a well defined concept and how it behaves conceptually can vary between different theoretical frameworks. Asking if time is created or explained by something in particular is assuming a standard definition already exists. So it would probably be better to just ask if time can be defined as slices of a higher dimensional object.

I would say that it can. But whether or not that definition satisfies you is another question. (Since it's still not clear if such a definition could explain change in general, e.g. what governs the change between slices?)

The idea is used in physics, you can look up the concepts of world lines, world sheets, world volumes, etc..

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    Time is extremely well defined. It's the numbers that your clocks show. Unfortunately some people have added a completely unnecessary and completely unscientific philosophical "time" concept on top of that. I have, indeed, no idea what that is supposed to mean. In physics, however, time is perfectly well defined by the clock that is used to measure it. – CuriousOne Dec 21 '15 at 19:48
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    While time is well defined, the OP is trying to relate time as a dimension to the other physical dimensions. I believe that is not a proper view of time. I can walk back and forth accross a room. I can't do that with time. Time assymetry is a fact for thermodynamics as well as quantum mechanics, although there is some work now to try to come up with ideas for time symmetry in quantum mechanics. – Peter R Dec 21 '15 at 20:16
  • CuriousOne - I do not think Time is on the whole well defined. It seems to be well defined only on a local "as needed basis" with no consideration of the whole yet available. For example, if the collapse of the wave-function is real, how could it not permeate instantaneously throughout the universe? Collapse changes all local probabilities and all local probabilities are linked through space. There are other incongruities about our current understanding of time. I plan to accept this answer by voidlike as the correct answer. – Waveforms Dec 21 '15 at 21:11
  • @PeterR: A timelike path can be directed toward the future or the past, but not both. A spacelike path can be directed toward the left or the right, but not both. That seems pretty symmetric to me. – WillO Dec 22 '15 at 00:49
  • Relativity was the last of the classical theories. It doesn't deal with the issues posed by thermodynamics nor quantum mechanics. – Peter R Dec 22 '15 at 01:40
  • my apologies to voidlike, I will accept John Rennie's answer above because I think follation is the key idea I want to read about. – Waveforms Dec 23 '15 at 00:35
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Is time created by movement through a higher dimensional object?

No. Time isn't actually "created" per se. And there is no movement through a higher-dimensional object. The block universe that people talk about models space at all times, so there's no motion in it or through it. However it's reasonable to say time is the result of motion through space. If you think about a clock, what it actually does is "clocks up" some kind of regular cyclical motion. This might be the motion of a pendulum, the motion of a rocker and cogs and gears, or the vibration of a quartz crystal. The inner mechanism of a clock is called a movement for good reason. The thing we call the time is effectively a cumulative measure of this movement, suitably displayed. Time is a dimension in the sense of measure, not in the sense of freedom of movement. I can hop forward a metre but you can't hop forwards a second.

In a comment I read on this page, someone mentions a theory where time is created by moving through and slicing "moments" of a higher dimensional object. For analogy, a 2-D creature living on a plane that moves through a 3-D object may experience the different slices of the 3-D object as "the passage of time" in their 2-D world.

It sounds like a garbled version of Eternalism, see Wikipedia:

"Eternalism is a philosophical approach to the ontological nature of time, which takes the view that all points in time are equally "real", as opposed to the presentist idea that only the present is real and the growing block universe theory of time in which the past and present are real while the future is not. Modern advocates often take inspiration from the way time is modelled as a dimension in the theory of relativity, giving time a similar ontology to that of space (although the basic idea dates back at least to McTaggart's B-Theory of time, first published in The Unreality of Time in 1908, only three years after the first paper on relativity). This would mean that time is just another dimension, that future events are "already there", and that there is no objective flow of time. It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time".

Is this idea well developed in physics?

I struggle to answer that. Eternalism and the block universe have been around for a long time, but there's no evidence at all of any 3D object moving through some higher-dimensional 4D object. The patent blatant evidence is that we live in a world of space and motion. This is modelled using spacetime, but the map is not the territory. You can't point up to the clear night sky and say "hey look, there's a worldline".

Can you share the name of this idea so that I can find it on google?

Eternalism is probably what you're looking for, and the growing black universe too, which mentions the spotlight. But I would encourage you to look into A World without Time: The Forgotten Legacy of Godel and Einstein. This concerns the opposite viewpoint which is called Presentism. Most people will tell you that Einstein and relativity is all about eternalism, but it isn't, it's all about presentism, because Einstein wrote equations of motion, not the equations of a static block universe.

Also, could dark matter play a role in this process?

No, sorry, dark matter is nothing to do with it.

John Duffield
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