Does Time Really Exist? A Philosophical Perspective

[Sapientiam]

Hello All,

I've read through a couple of forum posts on time but didn't find what I was looking for.

I've come to the conclusion that time doesn't actually exist and doesn't need to. However I'm always open for opposing points and would rather have a complete picture, even if I'm wrong.

My thoughts are this --

Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower" by comparing it to something else that changes, but changes extremely consistently. Generally these are Atomic Clocks. However if you put one of these Atomic Clocks near a binary star (imagine it isn't completely destroyed, etc) then that doesn't work anymore. I believe time needs to be standardized. E.g. theorize how an Atomic Clock(or replace with a better standard) would operate in the minimum(no external force, gravity, etc) and maximum(black hole, big bang, etc) environments. So essentially all there is is either faster or slower change, measured by another independent object. This also makes time travel impossible, which logically wasn't possible to begin with(grandfather paradox, etc). In conclusion I believe time is essentially the same as distance, temperature, etc. It is used to measure an aspect of change in a way humans can understand.

On a side note...
One of my major questions is, why is time required for existence? I still have not seen a good argument for this, mainly just people saying that without time the universe would not exist but that time can exist without the universe. Is this just an "je ne sais quoi" argument?

Any input is appreciated.

Thanks,
Sapientiam

 

[lubuntu]

Time seems to be inexorable from the idea of any "change" taking place. I don't think it makes a whole lot of sense to talk about a universe where time doesn't exist because that is something that would be entirely impossible for a human to experience. For us, for the universe we see, if we lose time we lose anything which might be called existence.

Also, a semantic issue that bothers me, time travel is indeed possible(your doing it right now) and in fact we can travel into the far future if we can accelerate to relativistic speeds, however time time to the past seems impossible. Why is that? Good question!

 

[Focus]

The problem with a question like this is what do you mean by exists? It is not really sensible to ask if an abstract concept to measure change, implemented by humans exists or not. It is exactly the same as asking if distance or volume exists.

 

[Sapientiam]

Time seems to be inexorable from the idea of any "change" taking place. I don't think it makes a whole lot of sense to talk about a universe where time doesn't exist because that is something that would be entirely impossible for a human to experience. For us, for the universe we see, if we lose time we lose anything which might be called existence.

Question: Why is it impossible for us to have experiences if time doesn't exist? You state it as a fact but do not answer why time is needed for it. Why if we lose time do we lose existence? Can you explain this? I see it stated as a fact over and over, but with no solid logic behind it.

Also, I don't think I came across my point clear enough. I believe time is still needed but that we are thinking about it incorrectly. We think of time as a "river" that can be contracted and expanded (slowing and speeding time). However, all this is is slowing down or speeding up change, in relation to another object (as I said before, generally an Atomic Clock).

Also, a semantic issue that bothers me, time travel is indeed possible(your doing it right now) and in fact we can travel into the far future if we can accelerate to relativistic speeds, however time time to the past seems impossible. Why is that? Good question!

If you consider the points I made, I'm not traveling through time right now but just experiencing change, with the amount of change being measured by time, relative to an Atomic Clock. Let's say however that I did somehow travel into the far future, what would be changed? Only me? Everything around me? Would I have done everything that I would have normally done? Probably not. This is because I am not actually traveling into the future, I am only speeding up change.

The problem with a question like this is what do you mean by exists? It is not really sensible to ask if an abstract concept to measure change, implemented by humans exists or not. It is exactly the same as asking if distance or volume exists.

This is my point. Distance and volume do not actually exist, they are concepts created by us to measure change. Same with time. Unless I'm understanding wrong, people consider time to be something that is "exists" in the sense that it can be manipulated. E.g. sped up and slowed down, travel into the future and possibly the past.


Also, quick question: If time (as we think of it now) is dilated by Gravity, etc then that would mean everything, everywhere is at a different point in time(even if it is only a small amount of time). How does that work?

Actually...second question: What do physicists consider traveling into the future? Would everything change or only the object that is being manipulated? E.g. if I went into space, traveled into the "future" and came back to Earth, would everything on Earth be in the "future" also? E.g. would it have changed at the same rate I did somehow? If it didn't, how can I tell that I actually traveled into the future?

 

[disregardthat]

Time is not only a system of measure of change, but the necessary medium in which change can occur, i.e. it is an ordering of events. Similarly, space is the definition of the necessary medium in which events can occur. Therefore, as our perspective of the world is a changing environment of events time and space must necessarily exist.

This is why it is equally meaningless to say that time and space don't exist as saying distance and volume don't exist. They are concepts which don't have the property of 'existence' similar to what one would call an object 'existing'.

The quantification of time is not equivalent to the existence of time in itself. We find atomic clocks to be extremely accurate in measuring equal intervals of what we define as time, and it is therefore natural to define the time unit on this. Time in itself is not a consequence of its quantification. That would be like saying that the concept of distance or volume is dependent on objects to measure.

 

[T.O.E Dream]

Hello All,

I've read through a couple of forum posts on time but didn't find what I was looking for.

I've come to the conclusion that time doesn't actually exist and doesn't need to. However I'm always open for opposing points and would rather have a complete picture, even if I'm wrong.

My thoughts are this --

Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower"

Hi, i just like to point out something, the words fast and slow both describe an object in motion or velocity. To determine velocity you have to divide distance by TIME i.e. v=d/t.
Also, change happens over TIME either really slow or very fast but either way they do take some TIME. Just so you know because the terms you used all relate to time.

 

[Astronuc]

Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower"

Hi, i just like to point out something, the words fast and slow both describe an object in motion or velocity. To determine velocity you have to divide distance by TIME i.e. v=d/t.
Also, change happens over TIME either really slow or very fast but either way they do take some TIME. Just so you know because the terms you used all relate to time.

Without 'Time', faster and slower makes no sense.

And the speed is measured as dx/dt, where x is some measure of distance or displacement (spatially) and t is measurement of time, and without acceleration or constant speed, v = Δx/Δt, where Δx = x₂-x₁ and Δt = t₂-t₁.

 

[Sapientiam]

Time is not only a system of measure of change, but the necessary medium in which change can occur, i.e. it is an ordering of events.

My question is: Why is time a necessary medium? We need time to measure WHEN the events happened, but we don't need time for the events TO happen.

Similarly, space is the definition of the necessary medium in which events can occur. Therefore, as our perspective of the world is a changing environment of events time and space must necessarily exist.

Exactly, from our perspective time and space must exist to measure change. However from an independent standpoint, do we really need time?

This is why it is equally meaningless to say that time and space don't exist as saying distance and volume don't exist. They are concepts which don't have the property of 'existence' similar to what one would call an object 'existing'.

I wasn't saying this. I was saying that currently we don't consider time as the same concept as distance, volume, temperature, etc. I didn't say distance, etc didn't exist, I was saying that we need to consider time as a concept similar to these.

The quantification of time is not equivalent to the existence of time in itself. We find atomic clocks to be extremely accurate in measuring equal intervals of what we define as time, and it is therefore natural to define the time unit on this. Time in itself is not a consequence of its quantification. That would be like saying that the concept of distance or volume is dependent on objects to measure.

As I said before, let's say we move that atomic clock near a binary star, does our time still hold true? No, because it is relative. Just because we as humans can live by this generally accurate time does not mean that it will hold true for the physics equations that are being written. Also, I was not saying time as a concept is exactly the same as distance/volume but holds many similarities. Similarities such as it doesn't exist until someone measures it(using a ruler, or maybe an atomic clock?).

Without 'Time', faster and slower makes no sense.

And the speed is measured as dx/dt, where x is some measure of distance or displacement (spatially) and t is measurement of time, and without acceleration or constant speed, v = Δx/Δt, where Δx = x2-x1 and Δt = t2-t1.

I'm not disputing this. I believe we need time to measure "faster" and "slower" but that it is relative. All I'm saying is we don't need time to "exist" for events to happen.


My overall point: I believe we need time to measure change but that time isn't needed for events to happen. Does anyone have any counterpoints to this?

Also, thank you everyone for all your reply's. It's helping me get a bigger picture of time and how it's used.

 

[Sapientiam]

Also, I've probably contradicted myself somewhere since I didn't have a clear view of what I was trying to explain but all the counterpoints are helping my grasp that clear view now. Thanks for all the replies.

 

[Sapientiam]

The quantification of time is not equivalent to the existence of time in itself. We find atomic clocks to be extremely accurate in measuring equal intervals of what we define as time, and it is therefore natural to define the time unit on this. Time in itself is not a consequence of its quantification. That would be like saying that the concept of distance or volume is dependent on objects to measure.

As I said before, let's say we move that atomic clock near a binary star, does our time still hold true? No, because it is relative. Just because we as humans can live by this generally accurate time does not mean that it will hold true for the physics equations that are being written. Also, I was not saying time as a concept is exactly the same as distance/volume but holds many similarities. Similarities such as it doesn't exist until someone measures it(using a ruler, or maybe an atomic clock?).

Actually I should take this back. Distance exists if it isn't measured, I guess the only similarity is that it is measuring something relative to something else. E.g. we measure distance by using the meter standard http://en.wikipedia.org/wiki/Metre the same way we measure time using an atomic clock.

 

[disregardthat]

My question is: Why is time a necessary medium? We need time to measure WHEN the events happened, but we don't need time for the events TO happen.

This is not about what why and how we use the concept of time, but whether it is a concept that should be considered as 'existing' or 'non-existing' in the same way as an object. In our perspective we observe events in an ordered sequence. As a part of the definition of time it is what allows us to experience events in an ordered sequence. The whole idea of change or order of events is related to the concept of time. Without time, we have no concept of change.

Compare it to the statement that "distance doesn't exist". Without distance, we have no concept of length. I.e. it would be meaningless to talk about length and still say that distance doesn't exist.

Exactly, from our perspective time and space must exist to measure change. However from an independent standpoint, do we really need time?

It isn't impossible to define a world without the concept of time. It would, however, not be what we percieve as our universe.

I wasn't saying this. I was saying that currently we don't consider time as the same concept as distance, volume, temperature, etc. I didn't say distance, etc didn't exist, I was saying that we need to consider time as a concept similar to these.

Well, you did say

Distance and volume do not actually exist

I'm not disputing this. I believe we need time to measure "faster" and "slower" but that it is relative. All I'm saying is we don't need time to "exist" for events to happen.

As previously mentioned, the concept of "fast" and "slow" lies within the concept of time.

 

[disregardthat]

Actually I should take this back. Distance exists if it isn't measured, I guess the only similarity is that it is measuring something relative to something else. E.g. we measure distance by using the meter standard http://en.wikipedia.org/wiki/Metre the same way we measure time using an atomic clock.

Actually, one meter is defined as the length light travels in one second divided by 299,792,458

 

[ThomasT]

Question: Why is it impossible for us to have experiences if time doesn't exist? Why if we lose time do we lose existence?

Our universe is evolving. Presumably, everything in our Universe is in motion. Time is an index of change or motion. If no time, then no motion. If no motion, then no Universe. If no Universe, then no existence.

I believe time is still needed but that we are thinking about it incorrectly. We think of time as a "river" that can be contracted and expanded (slowing and speeding time).

That might be the common view. It's probably a byproduct of our internal indexing of our sensory data, and a general lack of rigor wrt defining the meanings of the words we use.

What we're actually doing is associating accumulations of periodic oscillators with intervals of change or motion (incongruent spatial configurations). This is how we generate time indexes.

If you consider the points I made, I'm not traveling through time right now but just experiencing change, with the amount of change being measured by time, relative to an Atomic Clock.

We're, apparently, part(s) of an evolving Universe. We chart or index this evolution using clocks (internal and external). These indexes are what we call 'time'.

Afaik, the only way you could travel into the distant future would be to move veerrry faaast for a while. You can do the standard SR math. If you took a trip to the nearest galaxy and back, traveling at an average speed of, say, c/2, then even though you will have counted the same number of Earth-Sun years during your trip as the people who stayed on Earth, you will have aged much less than them.

Apparently, the periods of oscillators are lengthened by acceleration. The physical reason for this is unknown, afaik.

This is my point. Distance and volume do not actually exist, they are concepts created by us to measure change. Same with time.

I agree that they're concepts. But, concepts exist don't they? The time indexes that we internally and externally construct do exist, I think.

Unless I'm understanding wrong, people consider time to be something that is "exists" in the sense that it can be manipulated. E.g. sped up and slowed down, travel into the future and possibly the past.

I agree that this is a popular misconception of what time is.

Also, quick question: If time (as we think of it now) is dilated by Gravity, etc then that would mean everything, everywhere is at a different point in time(even if it is only a small amount of time). How does that work?

I think maybe this is just a semantic problem. You can adopt a holistic view of our Universe where this isn't a problem.

Actually...second question: What do physicists consider traveling into the future? Would everything change or only the object that is being manipulated? E.g. if I went into space, traveled into the "future" and came back to Earth, would everything on Earth be in the "future" also? E.g. would it have changed at the same rate I did somehow? If it didn't, how can I tell that I actually traveled into the future?

Well, if it didn't, then you probably didn't travel into the future. Anyway, afaik, as I said above, the only way you can travel into the distant future is by moving around real fast and aging at a slower than normal rate.

 

[SixNein]

Hello All,

I've read through a couple of forum posts on time but didn't find what I was looking for.

I've come to the conclusion that time doesn't actually exist and doesn't need to. However I'm always open for opposing points and would rather have a complete picture, even if I'm wrong.

Time is a very tricky topic, and many philosophers and scientist has debated time for years.

Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower" by comparing it to something else that changes, but changes extremely consistently.

I would define it like this: Observed time is a measurement of change within a margin of error.

Generally these are Atomic Clocks. However if you put one of these Atomic Clocks near a binary star (imagine it isn't completely destroyed, etc) then that doesn't work anymore.

Take two atomic clocks and set them equally in time. Put them in two different airplanes that are perfectly side by side on an extended runway. One airplane will travel east until it goes completely around the world and lands back on the runway. The other airplane will go west until it goes around the world and lands back on the same runway. Both airplanes never need to land, fly the exact same distance, and land at the same time. Both airplanes have equal acceleration and speed.

Will the two clocks be equal in time?

I believe time needs to be standardized. E.g. theorize how an Atomic Clock(or replace with a better standard) would operate in the minimum(no external force, gravity, etc) and maximum(black hole, big bang, etc) environments. So essentially all there is is either faster or slower change, measured by another independent object. This also makes time travel impossible, which logically wasn't possible to begin with(grandfather paradox, etc). In conclusion I believe time is essentially the same as distance, temperature, etc. It is used to measure an aspect of change in a way humans can understand.

Time cannot be standardized because it is relative to the observer.
http://en.wikipedia.org/wiki/Time_dilation

This also makes time travel impossible

First let's define time travel: "To go from present to a future date in such a fashion that a gap is created in the time-line where you do not exist."

I believe that is completely impossible.

On a side note...
One of my major questions is, why is time required for existence? I still have not seen a good argument for this, mainly just people saying that without time the universe would not exist but that time can exist without the universe. Is this just an "je ne sais quoi" argument?

Any input is appreciated.

Thanks,
Sapientiam

I don't think time is require for existence, but I believe it is require to perceive it.

 

[Sapientiam]

My question is: Why is time a necessary medium? We need time to measure WHEN the events happened, but we don't need time for the events TO happen

This is not about what why and how we use the concept of time, but whether it is a concept that should be considered as 'existing' or 'non-existing' in the same way as an object. In our perspective we observe events in an ordered sequence. As a part of the definition of time it is what allows us to experience events in an ordered sequence. The whole idea of change or order of events is related to the concept of time. Without time, we have no concept of change.

I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now? I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

Compare it to the statement that "distance doesn't exist". Without distance, we have no concept of length. I.e. it would be meaningless to talk about length and still say that distance doesn't exist.

Yea, I was completely wrong on this one. It made sense when I first thought about it but then I thought again...then again...and I still failed :P

Exactly, from our perspective time and space must exist to measure change. However from an independent standpoint, do we really need time?

It isn't impossible to define a world without the concept of time. It would, however, not be what we percieve as our universe.

I don't understand, why/how would our perception change?

I wasn't saying this. I was saying that currently we don't consider time as the same concept as distance, volume, temperature, etc. I didn't say distance, etc didn't exist, I was saying that we need to consider time as a concept similar to these.

Well, you did say

Distance and volume do not actually exist

Also, I've probably contradicted myself somewhere since I didn't have a clear view of what I was trying to explain but all the counterpoints are helping my grasp that clear view now. Thanks for all the replies.

This was one of those times, I fail :(

As previously mentioned, the concept of "fast" and "slow" lies within the concept of time.

I'm not debating this, we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

Question: Why is it impossible for us to have experiences if time doesn't exist? Why if we lose time do we lose existence?

Our universe is evolving. Presumably, everything in our Universe is in motion. Time is an index of change or motion. If no time, then no motion. If no motion, then no Universe. If no Universe, then no existence.

This interests me. Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

I believe time is still needed but that we are thinking about it incorrectly. We think of time as a "river" that can be contracted and expanded (slowing and speeding time).

That might be the common view. It's probably a byproduct of our internal indexing of our sensory data, and a general lack of rigor wrt defining the meanings of the words we use.

Agreed.

What we're actually doing is associating accumulations of periodic oscillators with intervals of change or motion (incongruent spatial configurations). This is how we generate time indexes.

This is going beyond me. What information does this time index hold?

If you consider the points I made, I'm not traveling through time right now but just experiencing change, with the amount of change being measured by time, relative to an Atomic Clock.

We're, apparently, part(s) of an evolving Universe. We chart or index this evolution using clocks (internal and external). These indexes are what we call 'time'.

Afaik, the only way you could travel into the distant future would be to move veerrry faaast for a while. You can do the standard SR math. If you took a trip to the nearest galaxy and back, traveling at an average speed of, say, c/2, then even though you will have counted the same number of Earth-Sun years during your trip as the people who stayed on Earth, you will have aged much less than them.

Apparently, the periods of oscillators are lengthened by acceleration. The physical reason for this is unknown, afaik.

This raises a lot of questions for me...
To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging? Would he notice he wasn't aging as fast? Would it feel like 10 years passed by to him? Where are the 5 missing years that he didn't age? If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years? It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

This is my point. Distance and volume do not actually exist, they are concepts created by us to measure change. Same with time.

I agree that they're concepts. But, concepts exist don't they? The time indexes that we internally and externally construct do exist, I think.

I don't know. It might be the way I think of the word, generally when I use it I think of an abstract idea that doesn't actually exist but is useful in describing something, but I don't think that's the definition for concept. I'll see if I can find a better word :P

Unless I'm understanding wrong, people consider time to be something that is "exists" in the sense that it can be manipulated. E.g. sped up and slowed down, travel into the future and possibly the past.

I agree that this is a popular misconception of what time is.

Isn't this partially what you are saying? Moving faster/slower speeds time up/down?

Also, quick question: If time (as we think of it now) is dilated by Gravity, etc then that would mean everything, everywhere is at a different point in time(even if it is only a small amount of time). How does that work?

I think maybe this is just a semantic problem. You can adopt a holistic view of our Universe where this isn't a problem.

How does it not become a problem? Wouldn't it be a bigger problem since the Big Bang is the most accepted starting point for the Universe? If time comes to an almost complete stop in a large gravitational pull how does anything happen?




Once again thanks for taking the time to post replies! This is making me think a lot more.

 

[disregardthat]

I don't understand why we need time in order to observe events in an ordered sequence.

This is exactly it. Time is the concept of the ordered sequences of events which, in any form you may suppose, is necessary for us to experience them. An eventless world would not be a world in which we could percieve anything. Hence time is the necessary medium for us being capable of this. The theory of relativity tells us, though, that the order of these sequences of events is not at all constant in other frames of referances.

 

[Sapientiam]

Hello All,

I've read through a couple of forum posts on time but didn't find what I was looking for.

I've come to the conclusion that time doesn't actually exist and doesn't need to. However I'm always open for opposing points and would rather have a complete picture, even if I'm wrong.

Time is a very tricky topic, and many philosophers and scientist has debated time for years.

Time is required, even if it doesn't exist, to measure how "fast" something changes. Instead of time there is only persistent change. Change can happen "faster" or "slower" by comparing it to something else that changes, but changes extremely consistently.

I would define it like this: Observed time is a measurement of change within a margin of error.

Generally these are Atomic Clocks. However if you put one of these Atomic Clocks near a binary star (imagine it isn't completely destroyed, etc) then that doesn't work anymore.

Take two atomic clocks and set them equally in time. Put them in two different airplanes that are perfectly side by side on an extended runway. One airplane will travel east until it goes completely around the world and lands back on the runway. The other airplane will go west until it goes around the world and lands back on the same runway. Both airplanes never need to land, fly the exact same distance, and land at the same time. Both airplanes have equal acceleration and speed.

Will the two clocks be equal in time?

Probably not, but not in any perceivable amount.

I believe time needs to be standardized. E.g. theorize how an Atomic Clock(or replace with a better standard) would operate in the minimum(no external force, gravity, etc) and maximum(black hole, big bang, etc) environments. So essentially all there is is either faster or slower change, measured by another independent object. This also makes time travel impossible, which logically wasn't possible to begin with(grandfather paradox, etc). In conclusion I believe time is essentially the same as distance, temperature, etc. It is used to measure an aspect of change in a way humans can understand.

Time cannot be standardized because it is relative to the observer.
http://en.wikipedia.org/wiki/Time_dilation

Yes I understand. There are lots of things relative to us however, we have Earth's Gravity, the Moon's the Sun's, etc but that does not stop us from using mathematics and logic to derive "standards" that seem to fit.

This also makes time travel impossible

First let's define time travel: "To go from present to a future date in such a fashion that a gap is created in the time-line where you do not exist."

I believe that is completely impossible.

Agreed.

On a side note...
One of my major questions is, why is time required for existence? I still have not seen a good argument for this, mainly just people saying that without time the universe would not exist but that time can exist without the universe. Is this just an "je ne sais quoi" argument?

Any input is appreciated.

Thanks,
Sapientiam

I don't think time is require for existence, but I believe it is require to perceive it.

Why is time required to perceive existence?

 

[Sapientiam]

This is exactly it. Time is the concept of the ordered sequences of events which, in any form you may suppose, is necessary for us to experience them. An eventless world would not be a world in which we could percieve anything. Hence time is the necessary medium for us being capable of this. The theory of relativity tells us, though, that the order of these sequences of events is not at all constant in other frames of referances.

Aren't the ordered sequences of events going to happen even if we don't measure them (with time)? Would they somehow not happen?

 

[SixNein]

Probably not, but not in any perceivable amount.

They wouldn't because of the rotation of the earth.

Yes I understand. There are lots of things relative to us however, we have Earth's Gravity, the Moon's the Sun's, etc but that does not stop us from using mathematics and logic to derive "standards" that seem to fit.

I think you misunderstand the idea of relativity. It does not mean relative to us as a group, but relative to each person. So two people could experience the same change but perceive different times. For example, take that clock example. If you had a 3rd clock sitting on the runway, it would be different from the others. To that observer, it would look like the planes took off and landed in the same amount of time. However, when you compare clocks, all of them are different.

Why is time required to perceive existence?

Because thought, perception, and all other senses require time. If you think of something new, then a change occurred. No time, no change.

 

[SixNein]

I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now? I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

Think of time as a movie. no time = pause. With Time = play.

I'm not debating this, we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

well it is an abstraction. You don't have to have a ruler to measure distance.

This interests me. Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

Time is like a number line that always goes forward. <-0-1-2-3-4-5-6-> (secs)
Between each number, an infinite amount of changes occur. We cannot measure time with that kind of accuracy, but take sort of a guess on the margin of error or ignore it entirely.

The past is being recorded by your brain. I'm guessing that everything would become perceived as very random without that ability.

This raises a lot of questions for me...
To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging? Would he notice he wasn't aging as fast? Would it feel like 10 years passed by to him? Where are the 5 missing years that he didn't age? If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years? It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

He would have counted 5 years, but the people on Earth would have said 10 years. No he wouldn't notice he wasn't aging as fast. We have had changes in our time due to orbits, but you didn't notice that change did you? =0)

Think of it as slowing everything down when you get faster. His thinking process takes longer, his aging takes longer, everything takes longer; however, he will not notice that change.

That is exactly what happens, change slows down as you go faster.

How does it not become a problem? Wouldn't it be a bigger problem since the Big Bang is the most accepted starting point for the Universe? If time comes to an almost complete stop in a large gravitational pull how does anything happen?

Things can be outside of a strong gravitational pull. We are outside of black holes yes?

 

[Sapientiam]

Yes I understand. There are lots of things relative to us however, we have Earth's Gravity, the Moon's the Sun's, etc but that does not stop us from using mathematics and logic to derive "standards" that seem to fit.

I think you misunderstand the idea of relativity. It does not mean relative to us as a group, but relative to each person. So two people could experience the same change but perceive different times. For example, take that clock example. If you had a 3rd clock sitting on the runway, it would be different from the others. To that observer, it would look like the planes took off and landed in the same amount of time. However, when you compare clocks, all of them are different.

I think this is an overused, oversimplified explanation for relativity. To the observer and the people in the planes, they took off and landed in the same amount of time. Just because the clocks are off does not mean that somehow "time" was changed for them. Think about how time is being measured. Why couldn't it be that change was occurring slower or faster due to external forces, making the clocks slower/faster?

Why is time required to perceive existence?

Because thought, perception, and all other senses require time. If you think of something new, then a change occurred. No time, no change.

I don't quite get the logic in this. Basically if we didn't exist, time wouldn't exist? I understand that we as humans need time as a concept to get by in day to day life but does that mean that time exists beyond our thoughts? Only we as cognitive beings need to think of time...everything else just changes.

 

[SixNein]

I think this is an overused, oversimplified explanation for relativity. To the observer and the people in the planes, they took off and landed in the same amount of time. Just because the clocks are off does not mean that somehow "time" was changed for them. Think about how time is being measured. Why couldn't it be that change was occurring slower or faster due to external forces, making the clocks slower/faster?

But time was changed for them and that is the important lesson here.Forces cause time dilation.

I don't quite get the logic in this. Basically if we didn't exist, time wouldn't exist? I understand that we as humans need time as a concept to get by in day to day life but does that mean that time exists beyond our thoughts? Only we as cognitive beings need to think of time...everything else just changes.

The process that time measures does exist. The clock on your wall, is an abstraction to measure that process.

 

[Sapientiam]

I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now? I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

Think of time as a movie. no time = pause. With Time = play.

This doesn't really explain anything. The Universe isn't even close to a movie :D Plus you can rewind movies.

I'm not debating this, we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

well it is an abstraction. You don't have to have a ruler to measure distance.

?

This interests me. Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

Time is like a number line that always goes forward. <-0-1-2-3-4-5-6-> (secs)
Between each number, an infinite amount of changes occur. We cannot measure time with that kind of accuracy, but take sort of a guess on the margin of error or ignore it entirely.

The past is being recorded by your brain. I'm guessing that everything would become perceived as very random without that ability.

This only specific to cognitive beings though.

This raises a lot of questions for me...
To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging? Would he notice he wasn't aging as fast? Would it feel like 10 years passed by to him? Where are the 5 missing years that he didn't age? If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years? It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

He would have counted 5 years, but the people on Earth would have said 10 years. No he wouldn't notice he wasn't aging as fast. We have had changes in our time due to orbits, but you didn't notice that change did you? =0)

Think of it as slowing everything down when you get faster. His thinking process takes longer, his aging takes longer, everything takes longer; however, he will not notice that change.

That is exactly what happens, change slows down as you go faster.

So he didn't actually travel into the future, the speed he was going at just slowed down any change. If I froze myself and unfroze myself 5 years later, I wouldn't say I traveled in time because everyone else was 5 years older.

How does it not become a problem? Wouldn't it be a bigger problem since the Big Bang is the most accepted starting point for the Universe? If time comes to an almost complete stop in a large gravitational pull how does anything happen?

Things can be outside of a strong gravitational pull. We are outside of black holes yes?

What about the Big Bang? When everything was in a sort-of black hole. How did anything get out if time was basically frozen and change couldn't occur?

 

[Sapientiam]

I think this is an overused, oversimplified explanation for relativity. To the observer and the people in the planes, they took off and landed in the same amount of time. Just because the clocks are off does not mean that somehow "time" was changed for them. Think about how time is being measured. Why couldn't it be that change was occurring slower or faster due to external forces, making the clocks slower/faster?

But time was changed for them and that is the important lesson here.


Forces cause time dilation.

How was time changed? When you say "time was changed" what you really mean is that their rate of change was slowed/sped up. If one plane had its rate of changed slowed, and one had it increased that wouldn't necessarily mean "time" has changed. It can mean that they aged faster/slower relative to the observer on the ground. Do you see the point I'm making?

 

[whybother]

******** philosophical musing doesn't make something deep.

Time exists in a sense different from just being space because if it wasn't different, then Lorenzian manifolds wouldn't need to be Lorenzian but would just be Riemannian.

The definition of time is very specific to the observer, but there is still a required notion of time in most cosmological models.

 

[SixNein]

This doesn't really explain anything. The Universe isn't even close to a movie :D Plus you can rewind movies.

If you could cause all the changes in the universe to go backwards, so would it it appear to be rewinding.

?

Time is to change as a ruler is to distance.

This only specific to cognitive beings though.

Yep

So he didn't actually travel into the future, the speed he was going at just slowed down any change. If I froze myself and unfroze myself 5 years later, I wouldn't say I traveled in time because everyone else was 5 years older.

That is correct.

I don't like the wording of "Time travel" because it's an abuse of relativity, and it creates confusion. When I use the word time travel, I expect gaps of non-existence in a time-line.

What about the Big Bang? When everything was in a sort-of black hole. How did anything get out if time was basically frozen and change couldn't occur?

I suppose the idea is that there was enough material that entered it to cause an ejection.

Sort of a rubber-band idea. Black holes are complicated and poorly understood even by modern day science.

Personally, while current evidence supports a big bang, I take the theory with a grain of salt. We have an extremely limited view of the universe because we can only observe a small section of it. We believe we are moving away from some galaxies faster then the speed of light, and will never be able to observe them. So truthfully, I don't think we have a clue about the origin of the universe.

Let me be clear, evidence supports a big bang theory; however, what we can observe is extremely limited.

 

[SixNein]

How was time changed? When you say "time was changed" what you really mean is that their rate of change was slowed/sped up. If one plane had its rate of changed slowed, and one had it increased that wouldn't necessarily mean "time" has changed. It can mean that they aged faster/slower relative to the observer on the ground. Do you see the point I'm making?

That is exactly what I mean, and yes it does mean time changed.

Have you ever paid attention to people walking as you drove down the road? You may be inclined to say that they appear to be moving slow. In fact, the faster you travel, the slower you will see them move.

 

[whybother]

That is exactly what I mean, and yes it does mean time changed.

Have you ever paid attention to people walking as you drove down the road? You may be inclined to say that they appear to be moving slow. In fact, the faster you travel, the slower you will see them move.

People moving at a relative velocity to you means that "time has changed"? How the hell are you defining time then?

 

[SixNein]

People moving at a relative velocity to you means that "time has changed"? How the hell are you defining time then?

Time is a professional business, make no mistake.

I would send you here for a better explanation then what I can give:
http://en.wikipedia.org/wiki/Time_dilation

 

[whybother]

Time is a professional business, make no mistake.

I would send you here for a better explanation then what I can give:
http://en.wikipedia.org/wiki/Time_dilation

Yeah, don't worry... I am familiar with the notion of time dilation, I assure you... what I meant was that I feel you are greatly confused to the actual profound question about the definition of time, because what you are talking about is not definition of time issues, it is just a fundamental misunderstanding of time and time dilation.

 

[SixNein]

Yeah, don't worry... I am familiar with the notion of time dilation, I assure you... what I meant was that I feel you are greatly confused to the actual profound question about the definition of time, because what you are talking about is not definition of time issues, it is just a fundamental misunderstanding of time and time dilation.

Last time I checked, speed effects time and the perception of it (at least in reference to others)

 

[Sapientiam]

How was time changed? When you say "time was changed" what you really mean is that their rate of change was slowed/sped up. If one plane had its rate of changed slowed, and one had it increased that wouldn't necessarily mean "time" has changed. It can mean that they aged faster/slower relative to the observer on the ground. Do you see the point I'm making?

That is exactly what I mean, and yes it does mean time changed.

Have you ever paid attention to people walking as you drove down the road? You may be inclined to say that they appear to be moving slow. In fact, the faster you travel, the slower you will see them move.

I don't see how this example directly applies to what we're talking about. Let me rewrite the example from before. Imagine there is a sun and two completely identical planets, in different orbits. Say Planet1, Planet2. Let's say Planet1 feels a large pull from the gravity of the sun and its change occurs slower relative to Planet2. What would be the difference between Planet1 and Planet2? Planet1 would be the "youngest" planet because it feels the most gravitational pull? Do the Planet's need "time" to explain why Planet1 is the youngest? No, it doesn't matter, they will do what they always do, uninfluenced by how fast or slow change is occurring for other planets. Only as humans do we care about how fast or slow something happens. I believe we are considering time, which is a human created concept, in the wrong fashion. We are trying to extend it to physics equations, even though we are not relating it correctly. Imagine that there is only change and that the change can be slowed or sped up in relation to things such as velocity, gravity, etc.

?

Time is to change as a ruler is to distance.

Isn't it Change is to time as a ruler is to distance?
In the sense that we use change to measure time and we use a ruler to measure distance.

 

[Sapientiam]

Yeah, don't worry... I am familiar with the notion of time dilation, I assure you... what I meant was that I feel you are greatly confused to the actual profound question about the definition of time, because what you are talking about is not definition of time issues, it is just a fundamental misunderstanding of time and time dilation.

Last time I checked, speed effects time and the perception of it.

But if your going 60MPH I doubt it's affecting "time" in any meaningful way, meaning all it is is your perception, which doesn't really matter in the bigger picture.

 

[whybother]

But if your going 60MPH I doubt it's affecting "time" in any meaningful way, meaning all it is is your perception, which doesn't really matter in the bigger picture.

Exactly.

 

[SixNein]

But if your going 60MPH I doubt it's affecting "time" in any meaningful way, meaning all it is is your perception, which doesn't really matter in the bigger picture.

No a change in time is occurring and the perception is changed as well, but the change in time at that rate of speed is extremely small. At the speed of light, time stops for you. So the faster you get, the slower time gets for you until it stops. If you was looking back traveling at the speed of light away from earth, people would appear to stand completely still.

 

[whybother]

No a change in time is occurring and the perception is changed as well, but the change in time at that rate of speed is extremely small. At the speed of light, time stops for you. So the faster you get, the slower time gets for you until it stops. If you was looking back traveling at the speed of light away from earth, people would appear to stand completely still.

You really need to be clear by what you mean as "time". Yes, "time dilation" is occurring, but the definition of time is still the same (ie. it's still the same observers time we're talking about). Meaning of time questions have nothing to do with time dilation, they have to do with observers.

 

[SixNein]

You really need to be clear by what you mean as "time". Yes, "time dilation" is occurring, but the definition of time is still the same (ie. it's still the same observers time we're talking about). Meaning of time questions have nothing to do with time dilation, they have to do with observers.

What do you mean by definition of time? Is it a process of measuring change, kind of definition?

Let me break this down more, but honestly that article did a good explanation.

Two observers, with synchronized watches.
First is standing still, in relation to the ground.
Second is moving at a velocity.

Effect #1 - Second is aging slower then first. The rate of change is depending on velocity.
Effect #2 - Second looks at the watch of frist, sees time is different. vise versa...

This is the werid one:
First is moving same velocity as second (side by side, same direction).
Effect #1 - Both should be aging at the same rate.
Effect #2 - Both see each others clock is slower then their own.

 

[Sapientiam]

You really need to be clear by what you mean as "time". Yes, "time dilation" is occurring, but the definition of time is still the same (ie. it's still the same observers time we're talking about). Meaning of time questions have nothing to do with time dilation, they have to do with observers.

What do you mean by definition of time? Is it a process of measuring change, kind of definition?

Let me break this down more, but honestly that article did a good explanation.

Two observers, with synchronized watches.
First is standing still, in relation to the ground.
Second is moving at a velocity.

Effect #1 - Second is aging slower then first. The rate of change is depending on velocity.
Effect #2 - Second looks at the watch of frist, sees time is different. vise versa...

This is the werid one:
First is moving same velocity as second (side by side, same direction).
Effect #1 - Both should be aging at the same rate.
Effect #2 - Both see each others clock is slower then their own.

Section 2, Effect #2 I think is the weirdest. But it still has an explanation. At those speeds, even though the person is next to you, you are seeing a delayed version of the clock. I would theorize that if they decelerated at the same rate and stopped at the same time, they would see the same time on both of their clocks.

See http://sheol.org/throopw/sr-superbowl.html

 

[disregardthat]

Aren't the ordered sequences of events going to happen even if we don't measure them (with time)? Would they somehow not happen?

That is like saying

"Don't objects have length even though we don't measure them (with distance)? Would they somehow not have length?"

As you can see it is meaningless to say that time does not exist. Time is the ordering of the sequence of events we know to happen which as a part of its definition is the necessary medium for us to experience events. How we measure events does not have anything to do with the 'existence' of time.

I would theorize that if they decelerated at the same rate and stopped at the same time, they would see the same time on both of their clocks.

Stopped?

 

[SixNein]

Section 2, Effect #2 I think is the weirdest. But it still has an explanation. At those speeds, even though the person is next to you, you are seeing a delayed version of the clock. I would theorize that if they decelerated at the same rate and stopped at the same time, they would see the same time on both of their clocks.

See http://sheol.org/throopw/sr-superbowl.html

Perception wise, light takes time to get to you. If your a very long distance from someone, you'll see them in the past.

My explanations pretty much sucked on this, so I would honestly suggest that you go to that link I pasted. Their explanations of the effect is so much better then mine lol.

It covers both aging and different perceptions of events.

 

[cam875]

the elegant universe explains it pretty good as well with nice examples.

 

[ThomasT]

I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now?

My guess is that we're not changing the order. There seem to be good reasons to believe that we're just charting or indexing it. So, the order of our historical records conforms, more or less, to the order of the evolution of our Universe.

Sometimes the word time is used to refer to reality as it unfolds via our streams of consciousness and sometimes it's used to refer to our records of reality. We can get the two mixed up if we're not careful, and maybe this is where our common sense ideas about traveling forward and backward in time come from -- as if time is something that we can zip around in like we do wrt our recollections of the past and projections about the future, as if, say, 1967 San Francisco is 'out there' somewhere right now. But, alas, I don't think it is.

General relativity seems to allow for time travel, but it seems destined to be replaced by a theory incorporating wave or particle (or both) dynamics which would seem to be a closer approximation to the apparently evolving and transitory Universe that we are part of -- and in a Universe like that, then time travel wouldn't be possible.

I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

The past seems to determine the future. The evolution of our Universe seems to proceed in the general direction away from past spatial configurations. There seems to be an 'arrow of time'.

... we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

I agree, but time is needed if the word 'time' is taken to be synonymous with the evolution of the Universe. And, as you've suggested, and I also agree with, our 'time-indexes' don't seem to be changing the general order of change.

Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

Movies, videos, a sequence of photos, time-stamped data streams, whatever is happening in our brains to process our stream-of-consciousness data to produce our recollections of the past, etc.

What information does this time index hold?

Different time indexes hold different information, depending on velocities and accelerations, etc. This is one reason why a theory like SR is so helpful. It gets everybody on the 'same page', so to speak -- so we can translate from one frame of reference to another.

To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging?

He kept a powerful telescope focused on our Solar System.

Would he notice he wasn't aging as fast?

Supposedly, he wouldn't feel any different than if he had stayed on Earth, except that he would feel any accelerations.

Things inside the spaceship would seem normal. Things outside the spaceship would look a bit weird. If he was continuously recording the feed from the telescope fixed on our Solar System he would see a rather wide range of planetary orbital rates wrt his outbound and inbound accelerations -- but as he landed he would have counted the same 10 years as those who stayed on Earth, even though his ship clocks and his internal 'clocks' would have accumulated only 5 years.

Would it feel like 10 years passed by to him?

Supposedly, no.

Where are the 5 missing years that he didn't age?

The periods of his internal oscillators, and any external oscillators moving with him, were lengthened wrt their periods when on Earth. He, and any 'clocks' moving with him changed less, marked less time, than those that remained on Earth.

If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years?

Inside his ship he counted 5 years. Wrt the Earth-Sun system he counted 10 years.

It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

That's the same thing, isn't it?

I don't know. It might be the way I think of the word, generally when I use it I think of an abstract idea that doesn't actually exist but is useful in describing something, but I don't think that's the definition for concept. I'll see if I can find a better word :P

I don't know. I didn't look it up. But I think of ideas as spatial configurations that physically exist somewhere -- even if it's only inside our brains.

Isn't this partially what you are saying? Moving faster/slower speeds time up/down?

Acceleration, apparently, affects the periods of oscillators. So, oscillators with different acceleration histories will have different accumulations of oscillations.

How does it not become a problem?

Ok, maybe it is a problem.

From our perspective inside our Universe, fapp, "... everything, everywhere is at a different point in time ...", as you said -- because the speed of light is finite.

So, to deal with our Universe as a whole, its constituents and overall spatial configuration at any given time or instant, and its evolution, it's necessary to adopt a 'birds-eye' view of things.
I think. I don't really know. Check with the Cosmology and Astrophysics people.

 

[Sapientiam]

Aren't the ordered sequences of events going to happen even if we don't measure them (with time)? Would they somehow not happen?

That is like saying

"Don't objects have length even though we don't measure them (with distance)? Would they somehow not have length?"

As you can see it is meaningless to say that time does not exist. Time is the ordering of the sequence of events we know to happen which as a part of its definition is the necessary medium for us to experience events. How we measure events does not have anything to do with the 'existence' of time.

I don't understand how it's meaningless to say time doesn't exist. Time=!Distance, so the comparison's aren't equal. Distance has physical qualities that can be seen, time is just a convenient invisible solution to a problem. Everything your saying is only from human perspective. Yes we need time to understand and conceptualize our universe but that doesn't mean it exists. If we didn't exist, "time" wouldn't exist either, nothing would be "indexing" the universe. Plus, we're indexing basically nothing in comparison to the size of the universe.

I would theorize that if they decelerated at the same rate and stopped at the same time, they would see the same time on both of their clocks.

Stopped?

You know what I mean :P Basically the more they slow down, the smaller the gap in the clocks.

Section 2, Effect #2 I think is the weirdest. But it still has an explanation. At those speeds, even though the person is next to you, you are seeing a delayed version of the clock. I would theorize that if they decelerated at the same rate and stopped at the same time, they would see the same time on both of their clocks.

See http://sheol.org/throopw/sr-superbowl.html

Perception wise, light takes time to get to you. If your a very long distance from someone, you'll see them in the past.

My explanations pretty much sucked on this, so I would honestly suggest that you go to that link I pasted. Their explanations of the effect is so much better then mine lol.

It covers both aging and different perceptions of events.

I did read it, it was the same examples with different wording. I will post some excerpts from the article and break them down in the end of this post.

I don't understand why we need time in order to observe events in an ordered sequence. If we didn't have time in the way we think of it now, how would the events be observed? Would they somehow be different? Would they not occur in the order they do now?

My guess is that we're not changing the order. There seem to be good reasons to believe that we're just charting or indexing it. So, the order of our historical records conforms, more or less, to the order of the evolution of our Universe.

Sometimes the word time is used to refer to reality as it unfolds via our streams of consciousness and sometimes it's used to refer to our records of reality. We can get the two mixed up if we're not careful, and maybe this is where our common sense ideas about traveling forward and backward in time come from -- as if time is something that we can zip around in like we do wrt our recollections of the past and projections about the future, as if, say, 1967 San Francisco is 'out there' somewhere right now. But, alas, I don't think it is.

General relativity seems to allow for time travel, but it seems destined to be replaced by a theory incorporating wave or particle (or both) dynamics which would seem to be a closer approximation to the apparently evolving and transitory Universe that we are part of -- and in a Universe like that, then time travel wouldn't be possible.

So essentially all "indexing" is is a function of consciousness. I don't see how indexing proves "time" exists beyond the concept we hold in our mind.

I understand we need time to help us as humans understand and measure the differences between "two points in time" but this is strictly for our use. Is the universe somehow aware that there was a past?

The past seems to determine the future. The evolution of our Universe seems to proceed in the general direction away from past spatial configurations. There seems to be an 'arrow of time'.

Every sentence says "seems" :) Anyway, how does the past determine the future? That only seems to hold true for conscious beings. Why because the Universe is expanding outwards does that mean that there is an "arrow of time"? As I said before, if time doesn't exist would things not follow the path they are now?

... we created the concept of time to measure the "fastness" and "slowness" of things, but time isn't needed for these "things" to exist is what I'm saying.

I agree, but time is needed if the word 'time' is taken to be synonymous with the evolution of the Universe. And, as you've suggested, and I also agree with, our 'time-indexes' don't seem to be changing the general order of change.

Yes I agree. We need "time" to measure the overall evolution of the Universe, but that does not mean time exists in the sense that it is "slowing" and "speeding" up. If this was true it would be impossible to tell when anything actually happened. Think about it. Imagine 5 billion years ago a sun was moving "slowly" through time so that it took 10 billion years to get where it would have been in 1 billion. How would we be able to tell? We couldn't. Think beyond this, as I said before if time "exists" that means everything is at a different point in time. Imagine if a black hole was created during the big bang, that would mean that we have something that is ~1 second old(ignore the math) even while our Universe is ~13B years old. How does this make sense? Can we tell what point in time things are at? If not, how do we figure out what time we're actually in or how old the universe actually is? This opens up some major holes in logic.

Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

Movies, videos, a sequence of photos, time-stamped data streams, whatever is happening in our brains to process our stream-of-consciousness data to produce our recollections of the past, etc.

Yes this is to help us, does it have any use beyond this function?

What information does this time index hold?

Different time indexes hold different information, depending on velocities and accelerations, etc. This is one reason why a theory like SR is so helpful. It gets everybody on the 'same page', so to speak -- so we can translate from one frame of reference to another.

Yes I understand as humans we need time to measure things, etc., but as I said before, how does that prove that time exists?

To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging?

He kept a powerful telescope focused on our Solar System.

You see how this example is falling apart now right? He couldn't count 10 years, he would need to base it on something else. And a telescope wouldn't help :)

Would he notice he wasn't aging as fast?

Supposedly, he wouldn't feel any different than if he had stayed on Earth, except that he would feel any accelerations.

Things inside the spaceship would seem normal. Things outside the spaceship would look a bit weird. If he was continuously recording the feed from the telescope fixed on our Solar System he would see a rather wide range of planetary orbital rates wrt his outbound and inbound accelerations -- but as he landed he would have counted the same 10 years as those who stayed on Earth, even though his ship clocks and his internal 'clocks' would have accumulated only 5 years.

As he landed he would have counted the same 10 years? How would he? Wouldn't he only notice 10 years had passed after he landed and saw what year it was?

Would it feel like 10 years passed by to him?

Supposedly, no.

Understood.

Where are the 5 missing years that he didn't age?

The periods of his internal oscillators, and any external oscillators moving with him, were lengthened wrt their periods when on Earth. He, and any 'clocks' moving with him changed less, marked less time, than those that remained on Earth.

Doesn't this prove my point? His oscillations were lengthened, making aging take "longer" in comparison to people on Earth. We measure the time with change. We compare the clocks on Earth to the clock on the ship. Without these physical representations, how would we know the difference in "time"? We couldn't. So doesn't it seem like a bit of a logic jump to use time to measure change once we get into these situations?

If he aged twice as slow, in the same amount of time, how does the slowing of time explain how he counted 10 years?

Inside his ship he counted 5 years. Wrt the Earth-Sun system he counted 10 years.

Basically "he" didn't count 10 years because he couldn't have. He got back to Earth and saw that it was 5 years later than what he thought it would be. He only believes an extra 5 years has passed because change was occurring for him twice as slow. The person isn't somehow in a different point in time.

It seems to me that, the faster you go, the longer the oscillations take, the longer it takes for the change to occur. This wouldn't really be slowing down time, but slowing down change...?

That's the same thing, isn't it?

Is it? Which do we use to measure the other one? We use change to measure time and set a standard. We can't use time to measure change and set a standard. Ask NIST. They don't measure time, they create it.

Isn't this partially what you are saying? Moving faster/slower speeds time up/down?

Acceleration, apparently, affects the periods of oscillators. So, oscillators with different acceleration histories will have different accumulations of oscillations.

This is where the problem is occurring. We use an atomic clock to set the standard for how fast oscillations should happen. Then we use this "standard" to measure and compare "time". What if we set the standard on Jupiter instead? Would that somehow mean that we're all moving through time slower, just because we're using a different standard? We need to look at how we're using "time" in a bigger picture. Everything is at the same "point" in time, if they weren't how would they interact with each other in our current definition of time? Things that are "farther back" in time don't interact with "older" versions of objects, they interact with the current versions.

How does it not become a problem?

Ok, maybe it is a problem.

From our perspective inside our Universe, fapp, "... everything, everywhere is at a different point in time ...", as you said -- because the speed of light is finite.

So, to deal with our Universe as a whole, its constituents and overall spatial configuration at any given time or instant, and its evolution, it's necessary to adopt a 'birds-eye' view of things.
I think. I don't really know. Check with the Cosmology and Astrophysics people.

That's what I'm trying to get a view of. I don't understand how everything could be in a different point in time but still be in the "present" too. This seems like an obvious contradiction to me.



How can we tell the difference between slowing time and slowing change? We use change to measure time, not the other way around. So is it correct to say time is dilating, or that change is slowing down? It seems like we're making a pretty large jump in logic here.

Second, I understand that time is relevant to us and is required for us to understand the advanced concepts of our universe but does it need to be in our equations that should be independent of human perspective? Human perspective means nothing in the bigger picture of the universe.

It seems to me that time slowing is just an illusion to humans because of the way our brains conceptualize time.

In the special theory of relativity, a moving clock is found to be ticking slowly with respect to the observer's clock. If Sam and Abigail are on different trains in near-lightspeed relative motion, Sam measures (by all methods of measurement) clocks on Abigail's train to be running slowly and, similarly, Abigail measures clocks on Sam's train to be running slowly.

I believe this is the example that was converted earlier. Once again, "clocks" which are actually just a measure of change are being used. In addition if your moving at those speeds your viewing an older version of their clock, which is why to both observers it seems that the other person's clock is running slow.

In contrast, gravitational time dilation (as treated in general relativity) is not reciprocal: an observer at the top of a tower will observe that clocks at ground level tick slower, and observers on the ground will agree. Thus gravitational time dilation is agreed upon by all observers, independent of their altitude.

This almost proves what I'm trying to explain. Gravity still affects rate of change but because the people aren't moving and seeing things "later" they see the same thing. Let me draw an example.

Let's say there is a point in space where gravity is extremely large. Place someone in that point with a clock. Place an observer 4 feet away and let's say the gravity doesn't affect him for some reason (use your imagination). The clock would tick slower, but both of them would still see the same time. The observer would see the clock ticking slower and the person moving slower. For the person in the gravitational pull "time" would still be passing as normal(assuming for some reason he wasn't crushed to nothingness).

 

[disregardthat]

I don't understand how it's meaningless to say time doesn't exist. Time=!Distance, so the comparison's aren't equal. Distance has physical qualities that can be seen, time is just a convenient invisible solution to a problem. Everything your saying is only from human perspective. Yes we need time to understand and conceptualize our universe but that doesn't mean it exists. If we didn't exist, "time" wouldn't exist either, nothing would be "indexing" the universe. Plus, we're indexing basically nothing in comparison to the size of the universe.

It was a proper analogy. You cannot see the physical quality of distance at all! You are defining a concept 'distance' and apply it to objects around you. Just because it is easier to think about doesn't make them different in a fundamental way. Everything we can say is from a human perspective, distance, volume and time are all human concepts. Time is a concept of the ordered sequence of events which is necessary for human experience. As we do experience, time must 'exist'.

 

[Phrak]

"Time exists" is an oxymoron.

 

[Sapientiam]

It was a proper analogy. You cannot see the physical quality of distance at all! You are defining a concept 'distance' and apply it to objects around you. Just because it is easier to think about doesn't make them different in a fundamental way. Everything we can say is from a human perspective, distance, volume and time are all human concepts. Time is a concept of the ordered sequence of events which is necessary for human experience. As we do experience, time must 'exist'.

Let's look at the two concepts that we're defining, one concept is even being used to define the other.

Standard distance = meter.
Standard time = second.

Meter = Distance light travels in a vacuum in 1/299,792,458 seconds.
Second = Duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

So, Meter = Distance light travels in a vacuum, on Earth, in 1/299,792,458 of the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.


Now, instead of the typical clock examples used for explaining physics let's use the caesium atom, the standard for time. Let's say we put a caesium atom on a ship moving at speeds near the speed of light. Would we say time slowed down for the caesium atom? How could you say that if it's the caesium atom that's defining time? You can't. What you can say is "...relative to the unmoving caesium atom on Earth..." So why is the caesium atom on Earth the standard for time? Wouldn't it be better to use something that has the least amount of external influence? At least then we could have a base. It seems to me that we are trying to define the Universe using standards that are only true on Earth.

 

[Sapientiam]

"Time exists" is an oxymoron.

True that.

 

[ThomasT]

So essentially all "indexing" is is a function of consciousness.

Pretty much everything we do is a function of consciousness, isn't it? The fact that you indexed something, either just internally or by making a publicly observable record, implies that you were aware of it, doesn't it?

But anyway, that's not the point we're pondering here -- at least I don't think it is.

You're saying that time doesn't exist. But I'm having difficulty understanding how you're using the word, 'time'.

If the word, 'time', refers to our individual streams of consciousness, our subjective apprehensions and private records of the world, and also to our public, objective records of the world, then it's sort of obvious that time exists.

I don't see how indexing proves "time" exists beyond the concept we hold in our mind.

Public, objective records. In SR the time of an event is the reading on a clock in the same frame of reference as the event. This is also one of the meanings of time in ordinary language. If you recorded a sequence of events, say with a video camera, and their associated times, then you'd have an objective time index of that set of events. Even without associating clock readings with frames of the video sequence, the video sequence itself is a time index of whatever it is that you're videotaping.

The problem is not 'proving' that time exists. We're just asking what the word 'time' means. How do we use the word? What does it refer to? Obviously it refers to something, and we're sorting out what that something is (or those somethings are, as the case may be).

... how does the past determine the future?

That's what the physical sciences are trying to learn.

That only seems to hold true for conscious beings.

Presumably, we emerged from and are ultimately constrained by the same fundamental dynamics that produced planets and stars and atoms and rocks and etc.

Why because the Universe is expanding outwards does that mean that there is an "arrow of time"?

The arrow of time refers to a preferred direction of change -- away from the past. We see that the past is different from the present. We see that the distant past was very different from the present -- and the very distant past even more different.

Another way to say this is that any particular instantaneous spatial configuration (eg., any photograph) of a large enough portion of our world, in an ordered set of, say, 10^10 photographs, is different from every other photograph in the set. They're all unique. If we compare photo 1000 to photo 1010 the differences are small. If we compare photo 1000 to photo 1,000,000 the differences are much greater. Photo 10^9 +1 will be unlike any previous photo, but it will be very similar to it's immediate neighbors in the sequence.

As I said before, if time doesn't exist would things not follow the path they are now?

But time does exist. It's a word, and that word refers to something. 'Time' has both technical and ordinary language meanings.

We need "time" to measure the overall evolution of the Universe, but that does not mean time exists in the sense that it is "slowing" and "speeding" up.

We use clocks of one sort or another, and make ordered records (time or clock indexes) of astronomical data. Time refers to both the (local) clock indexed data regarding astronomical evolutions and and to the astronomical evolutions themselves.

I don't know exactly what you're getting at with the second part ("slowing and speeding up") of your statement.

Apparently the universe has expanded/evolved at variable rates during its history.

If this was true it would be impossible to tell when anything actually happened.

If what was true?

We take photos or movies, or in other ways record events, of the world and time stamp them according to some convention.

Imagine 5 billion years ago a sun was moving "slowly" through time so that it took 10 billion years to get where it would have been in 1 billion.

You lost me here.

Things aren't moving "through time" as if time is something that exists independent of the motion or evolution of things.

How would we be able to tell? We couldn't.

Tell what? Do you mean that we don't have any absolute measure of duration or time interval? I agree.

The important thing is that we 'keep time' according to the same conventions.

... as I said before if time "exists" that means everything is at a different point in time.

I agreed with this before, but I've changed my mind. I'm not sure what it means.

But I'll say this. I can take a photo of the room I'm in at 8 pm, Wednesday, March 18, 2009 and say that the unique spatial configuration of the objects depicted in the photo correspond to my local time mentioned above. I also assume that there is a unique spatial configuration of my city, and state, and the USA, and the Earth, and the Solar System, ... and the Universe, corresponding to my local time mentioned above -- no matter what rate any of these systems might be 'changing' at according to my local clock.

Imagine if a black hole was created during the big bang, that would mean that we have something that is ~1 second old(ignore the math) even while our Universe is ~13B years old. How does this make sense?

It doesn't. If something created at the same instant our Universe was created is still around, then it's the same age as our Universe.

Can we tell what point in time things are at?

Yes, we refer to our time indexed historical records.

... how do we figure out what time we're actually in or how old the universe actually is?

I don't know exactly how they do that. It's is a question for the astrophysics forum.

Time is an index of change or motion? I'm probably wrong but does this somehow mean that the past is being recorded? How is this possible?

Movies, videos, a sequence of photos, time-stamped data streams, whatever is happening in our brains to process our stream-of-consciousness data to produce our recollections of the past, etc.

Yes this is to help us, does it have any use beyond this function?

Entertainment? Again, I'm not sure I'm understanding what you're getting at.

... I understand as humans we need time to measure things, etc., but as I said before, how does that prove that time exists?

What does the word, 'time', mean to you? How are you using the word?

If time refers to a clock reading, or a set thereof, or if time refers to the evolution of reality, then time exists.

To make it simple let's say the traveler traveled for 10 Earth-Sun years but only aged 5. How did he count 10 years in only 5 years of aging?

He kept a powerful telescope focused on our Solar System.

You see how this example is falling apart now right? He couldn't count 10 years, he would need to base it on something else. And a telescope wouldn't help :)

Yes he would count 10 revolutions of the Earth around the Sun. But the movie made vis the continual telescope feed would show a rather more erratic evolution of the Earth-Sun system for those 10 years than the steady one that those who stayed on Earth would observe.

As he landed he would have counted the same 10 years? How would he? Wouldn't he only notice 10 years had passed after he landed and saw what year it was?

He was continually viewing the Solar System through his telescope. The Earth would appear to move slower around the Sun as he accelerated away from the Earth, and it would appear to speed up as he turned around and decelerated to the Earth.

... doesn't it seem like a bit of a logic jump to use time to measure change once we get into these situations?

We associate the motion of certain systems with the motion of certain other systems. As long as we're all using the same standards and conventions, then we can communicate

Basically "he" didn't count 10 years because he couldn't have. He got back to Earth and saw that it was 5 years later than what he thought it would be.

No, he was continually looking through his telescope and counted the same 10 Earth-Sun revolutions that his Earthbound friends did. But on landing and checking the ship's clock, he noticed that it had only counted 5 years for the trip. He also noticed that his Earthbound friends seemed to have aged more than him, or he less than them during the 10 years of the trip.

He only believes an extra 5 years has passed because change was occurring for him twice as slow.

During his trip the Earth went around the Sun 10 times. This is as true for him as for those who stayed on Earth. But his internal oscillators and his ship's clock accumulated only half the number of oscillations that they would have had he stayed on Earth for those 10 years.

We can't use time to measure change and set a standard. Ask NIST. They don't measure time, they create it.

We associate the motion of certain systems with the motion of certain other systems. We agree to certain standards and conventions regarding an 'official' time. And we use this, and extrapolations of it, when talking about everything. It facilitates unambiguous communication.

This is where the problem is occurring. We use an atomic clock to set the standard for how fast oscillations should happen. Then we use this "standard" to measure and compare "time". What if we set the standard on Jupiter instead?

That would be a problem.

Would that somehow mean that we're all moving through time slower, just because we're using a different standard?

We're not moving "through time". We're just moving. Sometimes faster, sometimes slower. As is everything in the Universe.

We need to look at how we're using "time" in a bigger picture. Everything is at the same "point" in time, if they weren't how would they interact with each other in our current definition of time?

I agree.

Things that are "farther back" in time don't interact with "older" versions of objects, they interact with the current versions.

I'm not sure what you mean by this. The way I think about it, and what your previous statement seems to be in line with, is that the past doesn't exist except as historical records. There's a unique spatial configuration of the Universe corresponding to any given "point in time", and these spatial configurations are transitory, continually changing. What we call "the present" or "now" is just our record(s) of the most recent spatial configurations.

I don't understand how everything could be in a different point in time but still be in the "present" too. This seems like an obvious contradiction to me.

I agree. It would be a contradiction.

How can we tell the difference between slowing time and slowing change?

They're the same thing I think. We're just using the different words depending on the context.

We use change to measure time, not the other way around.

See above.

So is it correct to say time is dilating, or that change is slowing down?

If that's what's happening, then yes.

Second, I understand that time is relevant to us and is required for us to understand the advanced concepts of our universe but does it need to be in our equations that should be independent of human perspective?

Afaik, the basic equations of motion are time independent.

It seems to me that time slowing is just an illusion to humans because of the way our brains conceptualize time.

Sometimes it's just the symmetric artifact of convention, and sometimes two identical clocks will accumulate different times due to different acceleration histories.

 

[Math Is Hard]

This thread has really gone all over the map. I thought this was going to be a discussion more along the lines of whether or not a concept can be said to "exist" but that was not the case.

Many of the questions seem a better fit for our Relativity forum. I have moved the last post over there to get things started.
https://www.physicsforums.com/showthread.php?t=301036