- #1

thermia

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- 3

But if we delete the time dimesion it becomes inpossible to imagin. Whithout time there is no existence.

Could that mean that the time dimension is more fundamental than the other three?

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- Thread starter thermia
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- #1

thermia

- 19

- 3

But if we delete the time dimesion it becomes inpossible to imagin. Whithout time there is no existence.

Could that mean that the time dimension is more fundamental than the other three?

- #2

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- #3

Ibix

Science Advisor

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It's just a Euclidean space. I don't see the problem imagining it - we have been doing so since Euclid's time.But if we delete the time dimesion it becomes inpossible to imagin.

- #4

thermia

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Thanks for your reply. Of course flatland is highly improbable. My thought came from my inability to imagine a universe without time.

- #5

thermia

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Well, I was tryiing to imagine physical universes. Euclidian space is just math.It's just a Euclidean space. I don't see the problem imagining it - we have been doing so since Euclid's time.

- #6

itfitzme

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If you examine the measures of time in detail you will find that time is simply a measure of distance, more specifically a measure of cyclical distance. For instance, we measure time by counting the number of instances that the Sun moves around the Earth (celestial sphere).

But if we delete the time dimesion it becomes inpossible to imagin. Whithout time there is no existence.

Could that mean that the time dimension is more fundamental than the other three?

- #7

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But if we delete the time dimesion it becomes inpossible to imagin. Whithout time there is no existence.

Could that mean that the time dimension is more fundamental than the other three?

I'm not sure I would use the word fundamental, but your point seems trivially true. We can study motion and systems in 1, 2 or 3 spatial dimensions, but we always need a time dimension to get physics, as we know it.

- #8

thermia

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Yes, of course. But physisists have thught a lot about why the so called "time arrow" seem to be forced to go in just one direction, which may indicate that there is a fundamental difference between time and other dimensions.If you examine the measures of time in detail you will find that time is simply a measure of distance, more specifically a measure of cyclical distance. For instance, we measure time by counting the number of instances that the Sun moves around the Earth (celestial sphere).

I have been thinking that maybe all the dimensions are not created in exactly the same moment. I'm probably wrong but it is interresting to speculate about

- #9

thermia

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Thanks for reply. I understand you see my point :-)I'm not sure I would use the word fundamental, but your point seems trivially true. We can study motion and systems in 1, 2 or 3 spatial dimensions, but we always need a time dimension to get physics, as we know it.

- #10

Grinkle

Gold Member

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we always need a time dimension to get physics

if we delete the time dimesion it becomes inpossible to imagin

Also, I can imagine exactly one time dimension and I can imagine not moving at all or moving forward in that one dimenion. I have no idea what is implied by multiple time dimensions. I also don't have any intuitions that I trust at all regarding time travel to the past.

I can easily imagine 0, 1, 2 or 3 space dimensions, and I have intuitions that I trust regarding the implications of more than 3 spatial dimensions even if I can't make a mental picture of them.

But I don't know if that is anything more than an observation of human brain evolution.

- #11

thermia

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Well, that's the wall we allways are running into, aren't we? :-)But I don't know if that is anything more than an observation of human brain evolution.

- #12

jbriggs444

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What grounds do I have for considering t more "fundamental" than x? Why am I forced to consider that position x evolves over time t. Why can I not with equal rigor declare that time t evolves over position x?

- #13

thermia

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- #14

jbriggs444

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Lacking a measurement procedure, both are equally hypothetical. It is a distinction without a difference.

- #15

Nugatory

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It's different.Could that mean that the time dimension is more fundamental than the other three?

Does that mean that it's more fundamental? There's no answering that question unless someone provides a definition of "fundamental" that we can use to determine how fundamental something is and compare that with the "fundamentalness" of something else - and I'm not seeing that happening.

- #16

itfitzme

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And there's the problem, this imagined "time arrow" which supposedly might run in some other way. At it's core, physics is simply correlating on property with another. "Time" is label we give to one of these correlations. Fundamentally, physics is a study of how things change. There are cyclical changes that we recognize, the magnitude of voltage going up and down, the point end of the hand of a clock passing a mark "12" on its face, the change of a pulse of light as it goes down and back, reflecting off some distant mirror. The standards of weights and measures was devised so that we have a common reference for correlation. When we get down to the root of it, "time" is a measure of distance. A light year is the distance light travels compared to some other reference we have chosen as a cyclical distance. Time isn't some real property of space, it is the change of an object's position in space which we mark by correlating those positions to the swing of a pendulum that cycles in position in space.Yes, of course. But physisists have thught a lot about why the so called "time arrow" seem to be forced to go in just one direction, which may indicate that there is a fundamental difference between time and other dimensions.

I have been thinking that maybe all the dimensions are not created in exactly the same moment. I'm probably wrong but it is interresting to speculate about

- #17

Grinkle

Gold Member

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Time isn't some real property of space

That remark is not physics, whatever else it may be. General Relativity models spacetime and gives very specific attributes to space and time.

- #18

thermia

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A clever answer, well worth to consider, thank you.It's different.

Does that mean that it's more fundamental? There's no answering that question unless someone provides a definition of "fundamental" that we can use to determine how fundamental something is and compare that with the "fundamentalness" of something else - and I'm not seeing that happening.

- #19

itfitzme

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I find it an interesting think to wonder. The single observation that come close to the arrow of time is entropy. But this, as far as I know, is simply that things tend towards spreading out evenly across space. Again, we're down to that fundamental point of measure of distance, whatever changed position.Yes, of course. But physisists have thught a lot about why the so called "time arrow" seem to be forced to go in just one direction, which may indicate that there is a fundamental difference between time and other dimensions.

I have been thinking that maybe all the dimensions are not created in exactly the same moment. I'm probably wrong but it is interresting to speculate about

I have made some effort at finding some fundamental measure of time that doesn't involve a measure of distance and haven't. Always, in there, is that requirement of comparison to some other thing displaced in a spatial dimension, by convenience a cyclical displacement.

- #20

Grinkle

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I have made some effort at finding some fundamental measure of time that doesn't involve a measure of distance and haven't.

Does it make less sense to claim that a universe containing only a single static particle is getting older than to claim that same universe is expanding? For either case, I can't think of an experiment to define either older or bigger. My point is that I don't see how time is different from space in requiring some anchor points if one is to actually measure.

- #21

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I disagree 100%. A world without time is easy to imagine, it is just very boring.But if we delete the time dimesion it becomes inpossible to imagin.

- #22

thermia

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Interresting, could you elaborate some more about this?I find it an interesting think to wonder. The single observation that come close to the arrow of time is entropy. But this, as far as I know, is simply that things tend towards spreading out evenly across space. Again, we're down to that fundamental point of measure of distance, whatever changed position.

I have made some effort at finding some fundamental measure of time that doesn't involve a measure of distance and haven't. Always, in there, is that requirement of comparison to some other thing displaced in a spatial dimension, by convenience a cyclical displacement.

- #23

thermia

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I would say, not boring rather inexistingI disagree 100%. A world without time is easy to imagine, it is just very boring.

- #24

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Of course it is “inexisting”. What exists is 3 dimensions of space and 1 dimension of time. Anything else is automatically non-existent.I would say, not boring rather inexisting

That is far different from your claim of “inpossible to imagin”. I can imagine lots of non-existent things, and a universe without time is one of those.

- #25

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Do you have a professional scientific reference for this? Not just that some practical measuring devices use a measure of distance to measure time, but one that actually makes this general claim that time is a measure of distance?When we get down to the root of it, "time" is a measure of distance.

Decay time of unstable fundamental particles.I have made some effort at finding some fundamental measure of time that doesn't involve a measure of distance and haven't.

- #26

thermia

- 19

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That's an assumption, maybe you are rightOf course it is “inexisting”. What exists is 3 dimensions of space and 1 dimension of time. Anything else is automatically non-existent..

- #27

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All of the evidence supports the assumption. That is what science is about.That's an assumption, maybe you are right

Besides, you adopted that assumption in the OP, so it is odd for you to reject it now. You started out stipulating that you were talking about non-existent imaginary universes, but claimed that a universe without time is impossible to imagine. I disagree with that, it is easy to imagine.

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- #28

Riadh

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It is possible to artificially separate space and time however, by associating space with linear motion and time with circular motion. This is quite in tune with what we actually do in practice, as we measure time using oscillations of some sort. But this is only artificial, since to measure distance using light for example, we need to count the number of rotations or the time of flight as in modern official definition of the meter.

The counting of rotations/oscillations to measure time have the property that the count can only go up giving the required arrow of time. The zero of time (the present) can be chosen to be any number of rotations, with past before the zero and future after the zero. Finally since time is firmly related to motion, one can say the time has started with the first motion in the universe and will not stop before every motion stops everywhere.

- #29

thermia

- 19

- 3

Thank you Riadh for an extensive reply, well worth to consider.

It is possible to artificially separate space and time however, by associating space with linear motion and time with circular motion. This is quite in tune with what we actually do in practice, as we measure time using oscillations of some sort. But this is only artificial, since to measure distance using light for example, we need to count the number of rotations or the time of flight as in modern official definition of the meter.

The counting of rotations/oscillations to measure time have the property that the count can only go up giving the required arrow of time. The zero of time (the present) can be chosen to be any number of rotations, with past before the zero and future after the zero. Finally since time is firmly related to motion, one can say the time has started with the first motion in the universe and will not stop before every motion stops everywhere.

- #30

Likith D

- 65

- 1

This is what I gathered from wikipedia (it is mentioned that time is different from the spatial dimensions)

In fact they are mentioned under two different titles... the three being referred to as "spacial dimensions" and the other as "temporal dimension"

In fact they are mentioned under two different titles... the three being referred to as "spacial dimensions" and the other as "temporal dimension"

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- #31

slow

- 93

- 16

But if we delete the time dimesion it becomes inpossible to imagin. Whithout time there is no existence.

Could that mean that the time dimension is more fundamental than the other three?

Have you ever tried, say as instructional entertainment, to formulate basic mechanics without the variable called time? For example, instead of taking length, mass and time as fundamental magnitudes, take strength, length and speed. The first challenge you will find is to propose an operating procedure to measure speeds. The procedure to measure forces gives a little less problem. And the procedure for measuring length has been known since ancient times. If you do it, if you make observations and prepare data tables, in a short time you will see in the tables reasons to assume some hypothesis that inspire confidence. They inspire you at least within the limitations of your experiments. And you will also understand without much complication the need to define a function dependent on the force, the path traveled and how aligned or oblique the force is with respect to the path traveled. That is to say that defining work will be an obvious necessity. You will arrive intuitively and easily at the theorem of mechanical work and kinetic energy. And you would arrive even if you had never gone through a physics classroom or read anything about Newton. You would formulate a basic mechanics without introducing the time variable. And if after all that you want to establish a time definition, you will notice that there is no unique way to formulate a function ## t ## that satisfies the definition of time. The definition and function that you decide to adopt as a time formulation have no univocal relationship. You will also see that within the limitations of the experimental setup you have done, your tables of experimental values give a constant result when you divide the data of one column by the data of another, within the same row. That result does not change from one row to the others. So it is not wrong to assume that this quotient is a constant of each body that you have used in the tests. It is not wrong to suppose that to each body corresponds a value of that quotient, being that value independent of the speed, the force and the other conditions. That value is the mass and, only within the limitations of your essay, you have reason to consider it constant. The constant mass hypothesis complicates the form of the time function, whichever option you choose to formulate it. We could say more, but a button is enough to show.

The good thing about this didactic game is to understand that physics is not a fruit that nature has made and is hanging from a plant and is completely done, waiting for us to simply see it and take advantage of it. Physics, from its most basic beginnings, is a product that is made by mixing observations with logic, logic with supposed ideas (hypothesis), hypothesis with voluntary decisions to define magnitudes and functions, in a partially arbitrary way. The game of building basic physics without the definition of time teaches us to be prudent, austere and in favor of everything that helps avoid dogmatism.

Regarding time, it is an abstract function and it is impossible to build an instrument that directly measures time values. Everyone obtains data that is entered into the variables of the time function and gives a result that, conventionally, we decided to accept.

- #32

thermia

- 19

- 3

The way we chose to measure time is of course arbitrary and thus an abstract function. But time it self, regardless of how we measure it, is obviously fundamental physics.Have you ever tried, say as instructional entertainment, to formulate basic mechanics without the variable called time? For example, instead of taking length, mass and time as fundamental magnitudes, take strength, length and speed. The first challenge you will find is to propose an operating procedure to measure speeds. The procedure to measure forces gives a little less problem. And the procedure for measuring length has been known since ancient times. If you do it, if you make observations and prepare data tables, in a short time you will see in the tables reasons to assume some hypothesis that inspire confidence. They inspire you at least within the limitations of your experiments. And you will also understand without much complication the need to define a function dependent on the force, the path traveled and how aligned or oblique the force is with respect to the path traveled. That is to say that defining work will be an obvious necessity. You will arrive intuitively and easily at the theorem of mechanical work and kinetic energy. And you would arrive even if you had never gone through a physics classroom or read anything about Newton. You would formulate a basic mechanics without introducing the time variable. And if after all that you want to establish a time definition, you will notice that there is no unique way to formulate a function ## t ## that satisfies the definition of time. The definition and function that you decide to adopt as a time formulation have no univocal relationship. You will also see that within the limitations of the experimental setup you have done, your tables of experimental values give a constant result when you divide the data of one column by the data of another, within the same row. That result does not change from one row to the others. So it is not wrong to assume that this quotient is a constant of each body that you have used in the tests. It is not wrong to suppose that to each body corresponds a value of that quotient, being that value independent of the speed, the force and the other conditions. That value is the mass and, only within the limitations of your essay, you have reason to consider it constant. The constant mass hypothesis complicates the form of the time function, whichever option you choose to formulate it. We could say more, but a button is enough to show.

The good thing about this didactic game is to understand that physics is not a fruit that nature has made and is hanging from a plant and is completely done, waiting for us to simply see it and take advantage of it. Physics, from its most basic beginnings, is a product that is made by mixing observations with logic, logic with supposed ideas (hypothesis), hypothesis with voluntary decisions to define magnitudes and functions, in a partially arbitrary way. The game of building basic physics without the definition of time teaches us to be prudent, austere and in favor of everything that helps avoid dogmatism.

Regarding time, it is an abstract function and it is impossible to build an instrument that directly measures time values. Everyone obtains data that is entered into the variables of the time function and gives a result that, conventionally, we decided to accept.

- #33

slow

- 93

- 16

time it self, regardless of how we measure it, is obviously fundamental physics.

I have no reason to affirm or deny that opinion. I just want to confess that it does not seem obvious to me.

- #34

Mark44

Mentor

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I try to imagine two or three non-existent things each day before breakfast...I can imagine lots of non-existent things

- #35

thermia

- 19

- 3

My breakfast egg this morning was very close to become non existent :-) (Now time for bed)I try to imagine two or three non-existent things each day before breakfast...

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