# what we know about Time

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That reminds me a very old joke.

:-D

The height at one point is sufficient.

So I understand you correctly... if I draw a rectangle in the mass-time plane where mass is the width (the x axis) and time is the height (the y axis), to find the width of the rectangle I only need to measure it at one point? That doesn't imply that only that one point has width? The width of the whole rectangle can be the width of just that one point?

If so... What does this mean:

Oh, and I guess you believe also that mass increases with time, since you believe mass is a surface along the world line.

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:-D

So I understand you correctly... if I draw a rectangle in the mass-time plane where mass is the width (the x axis) and time is the height (the y axis), to find the width of the rectangle I only need to measure it at one point? That doesn't imply that only that one point has width? The width of the whole rectangle can be the width of just that one point?

If so... What does this mean:

Look, i am getting tired.

The width of a rectangle does not change, it is a basic property of a rectangle.

What I say is this:

In this space-time-mass diagram

_an object has mass

_mass is represented by height

_mass is connected to a point object

_a point object is represented by a point

_the point object at rest moves in time

_its trajectory over time follows a line

and

An object in space-time is not a line, the trajectory of a point-object in time is a line

An object in spacetime cannot exist at 2 time coordinates at the same space coordinate: it exist either then, either after, but not duplicately then and after.*

Exactly the same way an object cannot duplicate and exist at 2 coordinates in space at the same time.

This property of space is the same for time. Otherwise it would be impossible for space to transform in space and vice-versa.

IMHO to argue that a point object in spacetime is a line, is completely absurd.

*note: I feel like having to explain motion: you are here, you are there: you have moved. You have not duplicated. It is true for space, it is true for time.

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Look, i am getting tired.

The width of a rectangle does not change, it is a basic property of a rectangle.

Then, hopefully, you see what I mean? If a world line is an object and that line is projected into the mass dimension, that doesn't imply that the mass changes over time.

What I say is this:... the point object at rest moves in time

Does it move one day per day, two days per day, or three days per day? How fast does it move in time? If this is a meaningful concept then certainly we can measure it.

An object in spacetime cannot exist at 2 time coordinates at the same space coordinate

The sun can't be in the same spot yesterday and today? I could swear otherwise.

: it exist either then, either after, but not duplicately then and after.*

The sun either existed on march 1st or march 2nd... it can't be both...?

Is there a working model that would demonstrate?

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Then, hopefully, you see what I mean? If a world line is an object and that line is projected into the mass dimension, that doesn't imply that the mass changes over time.

Again: if the line is projected into the mass dimension, then the SURFACE is mass. In this case what we should measure as mass when examining an object should be mass/time and not mass. What I know from accepted science is that it is not the case.

Does it move one day per day, two days per day, or three days per day? How fast does it move in time? If this is a meaningful concept then certainly we can measure it.
Ha. Now you are asking about the rate of time. this is an open question in all cases.

The sun either existed on march 1st or march 2nd... it can't be both...?
exactly. If you want to make some calculation involving the mass of the sun at a certain coordinate in space at 1st of march, you cannot add in your calculation the mass of "another sun" at another coordinate in spacetime. You have to choose, one or the other.

Is there a working model that would demonstrate?

The existing model of accepted science will do.

To be honest, IMHO your idea of a massive object persisting in time is not compatible with accepted science. Mass does not extend over time. As we enter into the future we do not create new mass. And there is no "old mass" remaining in the past along our world line.

The sun can't be in the same spot yesterday and today? I could swear otherwise.

Standed corrected. I have to restate the concept in a different way.

I have to express the following concept: when you stare at the sun today at 12.00 and tomorrow at 12.00, supposedly at the same spot in the sky, it is the one and same sun and not a duplicated sun.

Edited by michel123456
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Again: if the line is projected into the mass dimension, then the SURFACE is mass. In this case what we should measure as mass when examining an object should be mass/time and not mass. What I know from accepted science is that it is not the case.

You've already agreed, you find the height of a line projected into a surface the same way you find the height of a point projected into a line. You've already agreed. You don't find the height of a square by multiplying length and width just because the square makes a surface. It is as simple as geometry gets. The height of a surface is not a surface area. C'est pas un travail de romain. I don't know what else to say.

No! You said objects move through time. I asked how fast. If you can't measure it that should tell you something.

If you want to make some calculation involving the mass of the sun at a certain coordinate in space at 1st of march, you cannot add in your calculation the mass of "another sun" at another coordinate in spacetime. You have to choose, one or the other.

I asked if the sun could have existed on march 1st and march 2nd. Your answer is that two suns cannot exist on march 1st. Do you see the disconnect?

The existing model of accepted science will do.

I wouldn't call science a model, and I've never heard of a scientific model saying the things you're saying, but perhaps you can show me one?

To be honest, IMHO your idea of a massive object persisting in time is not compatible with accepted science.

I wouldn't say that objects persisting in time is quite my idea. It would be widely considered common sense. In fact, you say the same thing,

I have to express the following concept: when you stare at the sun today at 12.00 and tomorrow at 12.00, supposedly at the same spot in the sky, it is the one and same sun and not a duplicated sun.

The object persisted in time means what you just said.

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You've already agreed, you find the height of a line projected into a surface the same way you find the height of a point projected into a line. You've already agreed. You don't find the height of a square by multiplying length and width just because the square makes a surface. It is as simple as geometry gets. The height of a surface is not a surface area. C'est pas un travail de romain. I don't know what else to say.

There is a communication issue. you don't use the term "projection" in the way I know it. "the height of a line projected into a surface" means nothing to me. "The height of a surface is not a surface area" is an indication of a misunderstanding of the word "height" in all our previous posts. I'll make a sketch for clarification.

No! You said objects move through time. I asked how fast. If you can't measure it that should tell you something.
That is not a new question. What is the "speed of time" is a dubious question that arises in fora at regular interval. In your way of understanding, there is also a kind of "rate of time", it is not an unique quality (or error) of my interpretation.

I asked if the sun could have existed on march 1st and march 2nd. Your answer is that two suns cannot exist on march 1st. Do you see the disconnect?
I see the disconnection: I say that the sun existed on march 1st and moved to march 2nd.

You say that the sun existed on march 1st and persist on march 1st and that the sun existed on march 2nd and persist on march 2nd. Sorry to say but it is full bogus to me.

I wouldn't call science a model, and I've never heard of a scientific model saying the things you're saying, but perhaps you can show me one?
I don't have the required authority to answer. I don't have the pretention to have build a new model, it is my understanding of accepted science.

I wouldn't say that objects persisting in time is quite my idea. It would be widely considered common sense.

I am not a fan of common sense.

In fact, you say the same thing,

Do I? shame on me.

The object persisted in time means what you just said.

?? No doubt there is a communication problem. I say the same sun moved in time, you say the sun persist. I don't understand the 2 concepts as the same thing.

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the vertical axis is Mass.

Each bold orange line correspond to the mass of an object at rest over time.

The questions are:

1.if the object is the base line, and if mass is associated to the object, then the SURFACE of the rectangle is mass and on the diagram the vertical axis should be labeled mass/time (and not mass)

2. it the object is a point on the base line, and if mass is associated to the object, then the diagram is correctly labeled: the LENGTH of each vertical orange line is mass.

3.do all the orange bold lines persist in time?

4.or are the vertical bold lines a succession of positions of a same object in time, IOW the object moves in time, it does not persist.

Edited by michel123456
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There is a communication issue. you don't use the term "projection" in the way I know it. "the height of a line projected into a surface" means nothing to me.

en géométrie dans l'espace, c'est une projection telle que la droite et le plan — quels que soient leurs rôles respectifs — sont perpendiculaires.

On your diagram the plane is the green square and the line is the t axis. See the definition above.

You said objects move through time. I asked how fast.

That is not a new question. What is the "speed of time" is a dubious question that arises in fora at regular interval.

Again, I didn't ask the speed of time. You said object move through time. I asked how fast they move through time.

I say that the sun existed on march 1st and moved to march 2nd... I say the same sun moved in time

How does one measure the speed of such a movement?

1.if the object is the base line, and if mass is associated to the object, then the SURFACE of the rectangle is mass and on the diagram the vertical axis should be labeled mass/time (and not mass)

No, the mass of the object is just the height of the green square. The mass axis is properly labeled. The height of a rectangle is the same as the height of a point on its base line. It really is just that simple.

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No, the mass of the object is just the height of the green square. The mass axis is properly labeled. The height of a rectangle is the same as the height of a point on its base line. It really is just that simple.

Ah, at least do you admit that a point on the line is an object (since mass is related to the object)?

Because in many of your previous posts you argued that the line is the object and that a point is an event (and not an object).

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Ah, at least do you admit that a point on the line is an object (since mass is related to the object)?

I didn't. A space-time coordinate is an event. Mass can exist at an event by way of an object intersecting that event. That doesn't make the event an object any more than having cat food in my pantry makes me a cat.

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I didn't. A space-time coordinate is an event. Mass can exist at an event by way of an object intersecting that event. That doesn't make the event an object any more than having cat food in my pantry makes me a cat.

That's a bit playing with words. But let's keep it.

In the last diagram, each orange line represents "Mass (...) at an event by way of an object intersecting that event".

So I understand that in your interpretation there is a LOT of mass in the 4d universe, because each orange line "persists". The full quantity of mass is equal to MT (mass multiplied by time) which is the surface of the green rectangle. Are you comfortable with that?

Edited by michel123456
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...is a LOT of mass in the 4d universe, because each orange line "persists"...

Events don't persist. Objects do. The height of each orange line is the mass present at each of those events. The height of the green square is the mass of the object that intersected each of those events.

How does one measure the speed of an object "moving through time"?

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Events don't persist. Objects do. The height of each orange line is the mass present at each of those events. The height of the green square is the mass of the object that intersected each of those events.

How does one measure the speed of an object "moving through time"?

Wait a moment: I thought you have said mass is connected to the object. Now you say mass is connected to the event. But you also say thas events don't persist?????

How do you want me not to be confused?

Mass persist or not?

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We know that mass slows down time as mass warps the space-time around it.

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I thought you have said mass is connected to the object. Now you say mass is connected to the event. But you also say thas events don't persist?????

Yes. Mass is a property of objects and events are related to objects.

How do you want me not to be confused?

Does it confuse you that not everything related to a barn is a horse?

I don't think you're confused.

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You avoided carefully my last question.

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You avoided carefully my last question.

Objects move how fast through time?

You didn't ask a question. You listed three non-contradictory sentences and put 5 question marks after them. Answer this:

Wait a moment: I thought you have said wet is connected to water. Now you say wet is connected to swimming. But you also say that swimming isn't an object?????

How do you want me not to be confused?

Wet is a property of water. Swimming is related to water.

Mass is a property of objects. Events are related to objects.

There is no contradiction. If you are confused -- I'm clearly unsuited to alleviating your confusion.

Edit,

Apologies...

Mass persist or not?

Of course mass persists. Do you think the earth will have no mass tomorrow? To persist means to continue to exist. Mass is a property of objects and objects persist. We've covered this persistently.

Edited by Iggy
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If mass persists, the past universe is filled with old mass.

Your concept is equivalent to say that time creates mass.

And MT should be a fundamental scientific feature.

At the question What is MT? the answer back in 2009 was:

Why does it have to mean something?

In the context of classical mechanics it does not ring any bells with me. It may not come naturally from Newton's laws or anything similar.

it doesn't have any named definition according to wolfram alpha and i can't find references to it. it probably just isn't a useful value.

Nobody has, as yet, matched that up with a physically meaningful/useful quantity.

So...... you invented something that makes no sense and you're asking us to make sense of it?

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If mass persists, the past universe is filled with old mass.

If mass persists, the past universe *was* (you've GOT to stop mixing your tenses) filled with what is now old mass.

Your concept is equivalent to say that time creates mass.

no, it is the equivalent of conservation of mass or saying that mass has time symmetry, neither of which are technically correct but good enough for the purpose of this conversation.

And MT should be a fundamental scientific feature.

At the question What is MT? the answer back in 2009 was:

I haven't read the thread and I would be afraid of pulling those quotes out of context. If "MT" has units kg*t then it doesn't have a name. I don't think any of the classical quantities like force, acceleration, energy, power, etc... have units where time is in the numerator.

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So for you the multiple orange lines in the diagram represent the concept of conservation of mass!

And if you wait longer the addition of new orange lines is also representing conservation of mass?

1. you have argued first that an object is a line.

2. you have argued that mass is related to the object.

3. after some questionning, you have changed your opinion and made the statement that mass is related to an event at the intersection with an object.

4. then you have agreed that an orange line on the diagram represents mass

5. now you say that the sum of all orange lines (a sum that grows with time) represents a law of conservation.

You don't have a strong case.

As an argument you asked several times

Objects move how fast through time?

About speed, that is the rate of displacement in space.

Speed is the ratio of a segment on the X axis (meters) by a segment on the Y axis (seconds) obtaining a result in units m/sec.

You can flip the X and Y axis so that X represents time (seconds) and Y space (meters). The ratio gives thus a result in units sec/m which is not speed but inverse speed. Call that as you want, "invspeed" for example.

Well, for an object at rest, invspeed of time is infinite.

Note: this is not speculation, it is a simple mathematical inversion.

Edited by michel123456
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So for you the multiple orange lines in the diagram represent the concept of conservation of mass!

If all the orange lines on a world line have the same height in the mass dimension then mass is conserved, correct.

1. you have argued first that an object is a line.

The usual definition of "object" corresponds directly to a world line on a space time diagram, yes.

2. you have argued that mass is related to the object.

Mass is a property of objects, correct.

3. after some questionning, you have changed your opinion and made the statement that mass is related to an event at the intersection with an object.

Again, mass can be a property of objects and related to events... just like... wet can be a property of water and related to swimming. Do you *really* not understand?

4. then you have agreed that an orange line on the diagram represents mass

Yes, it is the mass of the object or objects intersecting that event. It is the height of the rectangle. So what?

5. now you say that the sum of all orange lines (a sum that grows with time) represents a law of conservation.

Please, show me where I said the sum of the orange lines or apologize.

The ratio gives thus a result in units sec/m which is not speed but inverse speed. Call that as you want, "invspeed" for example.

Well, for an object at rest, invspeed of time is infinite.

I am moving through time at infinite seconds per meter and this somehow implies that I either had mass in 2000 or 2001?

I don't think so.

I think you mean something entirely different when you say "an object moves through time".

Edited by Iggy
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Does anyone split time from anything? I thought a lot. I could not image how time stand alone. So I suppose time is a property of object, which means time is created by object.

Such as, a day means "one circle of earth self-rotation", means a day is created by earth self-rotation. A year means "one circle of earth orbiting sun", means a year is created by earth orbiting sun.

Does this make any sense?

Suppose earth self-rotation is a bit longer or shorter, will a day changes into one and a half days or half day? I don't think so. My point is "A day is the time created by earth self-rotation".

After all, my viewpoint about time is that:" Every existing things creates its own time. "

A funny viewpoint , isn't it?

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When a dicussion about Time begins, it usually derails into philosophical blah blah after a post or 2.

I'd like to refrain from the philosophical tentation, and try to concentrate on what we really know about Time from a scientific point of vue only.

For example:

1. we know that motion requires time: nothing can move from one spatial coordinate to another in zero time, it would be a transgression of the Speed Of Light.

2. we know that the rate of time is related to gravity: where gravity is stronger Time flows slower.

3. we know that time has a "direction", commonly called the arrow the time.

4. we know that time is related to causality, and causality is related to c, the Speed Of Light.

5. we know that time is linked to space: time alone has no physical meaning, only the spacetime continuum "exists".

6. we know that time can transform in space, and vice-versa: what is space for an observer may be time for another.

What else do we know about Time? (and please correct me for any error)

With all due respect for your wish to keep this inquiry scientific and avoid philosophy/onbtology of time, I must disagree with some of your "we know" assertions above.

#1; check. Agree.

Regarding #2:

We know that higher gravity fields make clocks oscillate ("tick") more slowly. This is what we observe, which is the essence of empirical science.

2. we know that the rate of time is related to gravity: where gravity is stronger Time flows slower.

...Goes beyond what we observe empirically, as I said above, and asserts that time 'itself' ('an entity') has a "rate and that 'it' "flows" slower where gravity is stronger.

3. we know that time has a "direction", commonly called the arrow the time.

'It' must be an entity of some kind to "have direction." The commonly used phrase, "arrow of time" is a misleading metaphor which supports the *assumption* that time is "something" that is going somewhere in a certain "direction."

4. we know that time is related to causality, and causality is related to c, the Speed Of Light.

"Related" how? Are you assuming that time is an agent of causation rather than a description of what "elapses" (in various conventional time units) as things move?

And how does light traveling at 'c' become an agent of cause?

5. we know that time is linked to space: time alone has no physical meaning, only the spacetime continuum "exists".

What do you mean by "linked to space?" We all know that "it takes time" for light and info to travel through space and for all things to move, so I'll go with that as a "link" without the reification factor, making "something" of time.

Given that "spacetime" is a coordinate system, a model that works for relativity, I must ask what you mean by the ontological assertion that it "exists" (other than as a model or map.)

6. we know that time can transform in space, and vice-versa: what is space for an observer may be time for another.

You are claiming that "we know" that time and space can be interchangeable for different "observers."

Since ontological discussion of what time and space *are* is not allowed, being merely philosophical, how can you seriously assert that "they" are interchangeable "for" different observers, whom, of course have different realities depending on their different perceptions... no 'cosmos as it is' independent of observation allowed here as an alternative "what we know."

What else do we know about Time? (and please correct me for any error)

As you can see, I took your invitation seriously, told you what I know about time, and corrected your *assumptions* about time which you assert as proven knowledge, "what we know."

Edited by owl
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Time is very dificult to pin down, I'm very interested to see how this thread turns out and if people can keep philosophy out of the thread...

7 pages, 122 posts, and not in Speculations, not bad.

(...)Do you *really* not understand?

No, not *really*.

You are quite convincing. anyway your point of vue is the commonly accepted on the basis of common sense, as you said before.

I'll try to find another analogy:

What you say is that when you progress in time, you leave an indelebile imprint on each spacetime coordinates that you have occupied.

Like the skateboarder below

Your POV is also to imagine that if you are standing still sitting on your chair, time flows over you, like a strong wind extracting an imprint from your presence in spacetime. As if you were inside an extruding machine.

Compare that to my POV: as the skateboarder changed coordinates in space, he also changed coordinates in time. So simple.

Edited by michel123456
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michel,

I am sorry if my post of 3/20 intimidated you. I thought you were serious about discussing "what we know about time," and I considered each of your points respectfully.

I really wish you would reply to my post. Tell me how you think I am wrong at least.

This is a scientific discussion of what we "know" about time, is it not?

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michel,

I am sorry if my post of 3/20 intimidated you. I thought you were serious about discussing "what we know about time," and I considered each of your points respectfully.

I really wish you would reply to my post. Tell me how you think I am wrong at least.

This is a scientific discussion of what we "know" about time, is it not?

_I didn't want to disturb my duel with Iggy

_your post was quite negative. Instead of putting new information, you are destroying the few we have.

For sure al discussions about time are surrounded by a peplum of mystery. It is obvious that no one of us exacltly knows what he is talking about (a reason why so few members are engaged in the discussion). We gave a name to "something" we call "time" without knowing if it is "something". It may be a property, it may be an illusion, it may be nothing, we don't know yet. But I think that with a little cleverness, we can catch devil's tail.

Philosophy doesn't help. As you may have noticed, after seven pages of argumentation, even the simple concept of what is occuring remains unclear.

For Iggy, the Past Light Cone is (was) filled with mass that persists (persisted).

For me the surface of the Past Light Cone is occupied by our companions traveling with us in time.

Etienne Klein wrote (sorry for my word-by-word translation from french) " We already said that when the language speaks about time, it does it often in the wrong way. What does it mean when, for example, we are repeating that time "flows", "passes through", "vanishes"? This way of talking which associates time with lability and escape, has become common. By the way, it is not neutral. First of all, it is a language abuse. Nobody is arguing that we may say that time is made from any thing that passes. But to deduct that it is time itself that passes through is making a shortcut and confusing content and container (“contenant et contenu”, which means also subject and object). The succession of the instants of time (past, present, future) is not the same thing that the evolution (“succession”) of time itself. They (the instants) pass, it (the time) does not. Then,, why is it more correct to say that time passes through than to say that the road is moving (“le chemin chemine”) or that a music book is singing? If we admit that any reality is temporal, saying that time is passing through is equal to say that, in reality, what is passing through is the sum of things and phenomenas that are containing by time. In a few words, it is the entire reality that passes through, and not time itself”

From « DOES TIME EXIST? ( LE TEMPS EXISTE-T-IL?) » ed. Le pommier, 2002, pg 22,23. The smallest (and most condensated) book on my bookshelves.

Etienne Klein is a physicist and phd in philosophy, working at CEA (French Commissariat a l’Energie Atomique) and professor at Ecole Centrale de Paris.

I agree with him: the entire reality passes through, and not time itself.

I guess Iggy agrees with that statement. The question is that Iggy perceives that "passing through" in a fundamental different way than I do. For me things move in time exactly the same way they move in space, Iggy disagrees and say that moving in time is a form of progression that leaves mass in the past (if i understand correctly his POV).

The funny thing is that both Iggy & me are arguing that they speak in accordance with accepted science, although we cannot both be right. One of us must be blatantly wrong.

Edited by michel123456

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