Is Time Travel Possible and Already Happening in Our World?

[epkid08]

Two objects lie motionless in an isolated frame. One object accelerates to a speed v, then then holds that speed for an amount of time t. This causes the accelerated object to travel a time [tex]t_s[/tex] into the still motionless object's future.

[tex]v=\frac{c\sqrt{t_s^2+2t_st}}{(t_s+t)}[/tex]

If you're wondering I defined [tex]t_s[/tex], time skipped into motionless object's future, equal to [tex]t_c-t_p[/tex], coordinate time minus proper time. Solve for coordinate time, and plug it into the time dilation equation. Then solve for v.

This seems like it would have multiple applications for various preserving/maturing things i.e. foods, alcohol in our world.

Has anyone seen this before? Is it correct? Is it applied in our world today?


Also a question that is not about this topic.
Theoretically, if an object is motionless in a vacuum with 0 forces acting on it, does it experience time? Apparently, most people view time as a philosophical thing more than anything, but furthermore a consequence of motion. So my question is just that, is time just a consequence of motion?

 

[matheinste]

Hello epkid08.

Can we be motionless in time as well as space?. I think we are always moving forwards in time. Time and space are united as spacetime and i think there is a condition that that our wordlines be always future directed.

Matheinste.

 

[epkid08]

Hello epkid08.

Can we be motionless in time as well as space?. I think we are always moving forwards in time. Time and space are united as spacetime and i think there is a condition that that our wordlines be always future directed.

Matheinste.

Heh, I was going to add in parenthesis that it's impossible to do so, but I didn't. I think my main question was is time truly just a consequence of motion, or is it a truly unique 'dimension' that applies to all space. I suppose both could very well could mean the same thing, it's just how someone thinks about it.

 

[epkid08]

It doesn't seem like I explained things well enough because no one posted, so I will try again.

If we have the coordinate time of an object, [tex]t_c[/tex], and we have the proper time of an object, [tex]t_p[/tex], we can see that with a velocity of 0, they are the same. As the object accelerates, [tex]t_c[/tex] increases at a much higher rate than [tex]t_p[/tex]. When the object decelerates back to 0, depending on the velocity and proper time, the object will see that the observer has aged a given amount of time more than the object did. We can define this extra time as 'time the object skipped into the observers future', [tex]t_s[/tex]. Obviously, [tex]t_s[/tex] can be easily calculated by taking [tex]t_c-t_p[/tex]. From here the variables can be rearranged in many various ways. I will solve for [tex]t_s[/tex] first, then for velocity.

[tex]t_s=t_c-t_p[/tex]
[tex]t_c=t_s+t_p[/tex]
[tex]t_p\gamma -t_p=t_s[/tex]
[tex]t_p(\gamma -1)=t_s[/tex] (1)


[tex]\gamma =\frac{t_p+t_s}{t_p}[/tex]
[tex]\sqrt{1-v^2/c^2}=\frac{t_p}{t_p+t_s}[/tex]

Skipping some steps...
[tex]v=\frac{c\sqrt{t_s^2+2t_pt_s}}{(t_s+t_p)}[/tex] (2)

In words:
Two objects lie motionless in an isolated frame. One object accelerates to a speed v, then then holds that speed for an amount of time t_p. This causes the accelerated object to travel a time [tex]t_s[/tex] into the still motionless object's future.

I've never seen this derived version of relativity. It seems like this could be applied in multiple ways in our world.

Is the derivation correct? Is it applied in our world?

 

[MeJennifer]

This causes the accelerated object to travel a time [tex]t_s[/tex] into the still motionless object's future.

Sorry but that statement does not make any sense to me.

 

[epkid08]

Sorry but that statement does not make any sense to me.

If an object travels at v>0, while its observer is stationary, the moving object will experience a slower rate of time than the still stationary observer. This change in time is shown by [tex]t_s[/tex]. Whether or not you want to call it 'time travel' really makes no difference. Is there a better phrase for it?

 

[isly ilwott]

I have difficulty believing that a motionless object does not experience time. I see no connection between the period of time in which an object exists and the distance it may or may not have traveled in that time period.

 

[MeJennifer]

If an object travels at v>0, while its observer is stationary, the moving object will experience a slower rate of time than the still stationary observer.

And how would you propose to determine who is traveling and who is stationary?
An object is only moving relative to another object.

 

[epkid08]

And how would you propose to determine who is traveling and who is stationary?
An object is only moving relative to another object.

Ahem, treat velocity as a vector.

 

[epkid08]

I have difficulty believing that a motionless object does not experience time. I see no connection between the period of time in which an object exists and the distance it may or may not have traveled in that time period.

If we define proper time strictly as a consequence of motion, then an object without motion (this will never happen), will also be without time.

 

[MeJennifer]

Ahem, treat velocity as a vector.

A vector?

You and I are in empty space and we see that the distance between us is constantly changing, who is moving?

Where does your vector come in?

If we define proper time strictly as a consequence of motion, then an object without motion (this will never happen), will also be without time.

Your comments are getting increasingly more bizarre to me.

 

[isly ilwott]

If we define proper time strictly as a consequence of motion, then an object without motion (this will never happen), will also be without time.

Quite so...if you define it that way. If I define black as white then all things white are actually black. Your definition is errant.

Also, your claim that an object without motion will never happen is errant. Once you have established a vantage point, anything that does not move in relation to it is without motion.

 

[isly ilwott]

Ahem, treat velocity as a vector.

Whether treated as a vector or not, the reference point will determine which is moving.

Velocity in commonly treated as a vector. The magnitude of an object's speed coupled with the direction of travel yeilds the object's velocity. For both parameters, there must be a reference point.

 

[MeJennifer]

Whether treated as a vector or not, the reference point will determine which is moving.

Coordinate and frame wise yes, physically no. Physically they are simply moving with respect to each other.

 

[isly ilwott]

Coordinate and frame wise yes, physically no. Physically they are simply moving with respect to each other.

The motion must be referenced to something

To a person on a speeding train, the dining car is not moving, but the track is. To a person standing on the track, the train is moving but the track is not. In order to determine the relative motion of any object, a reference point must be utilized.

 

[epkid08]

Quite so...if you define it that way. If I define black as white then all things white are actually black. Your definition is errant.

At the beginning of the topic I used that as the definition because it's a widely accepted view on it, I'm not even saying it's the right view of it, my intention was to get a better perspective on it.

Also, your claim that an object without motion will never happen is errant. Once you have established a vantage point, anything that does not move in relation to it is without motion.

There is no such thing as a true isolated frame, gravity will always be there, and thus there will always be a real force acting on an object.

A vector?

You and I are in empty space and we see that the distance between us is constantly changing, who is moving?

Where does your vector come in?

Are you saying it is impossible to observe a 'left' and a 'right'? If the object is traveling relative to the observer, the object is traveling at v; if the observer is traveling relative to the object, the observer is traveling at -v.

Your comments are getting increasingly more bizarre to me.

It was not directed to you.

Whether treated as a vector or not, the reference point will determine which is moving.

Velocity in commonly treated as a vector. The magnitude of an object's speed coupled with the direction of travel yeilds the object's velocity. For both parameters, there must be a reference point.

There doesn't need to be a reference point, as I said before if the object is moving relative to the observer, the object is traveling at v, if the observer is moving relative to the object, the observer is traveling at -v. This is because the object can distinguish the x coordinate relative to observer, and vice-versa.

 

[MeJennifer]

The motion must be referenced to something

Not true, in relativity motion is always relative. Don't mix up physical reality with frames and coordinate systems.

 

[isly ilwott]

Not true, in relativity motion is always relative. Don't mix up physical reality with frames and coordinate systems.

It seems a physical reality to me that in speaking of physical objects, the motion of any object must be measured in reference to something else, namely the reference point.

 

[epkid08]

It seems a physical reality to me that in speaking of physical objects, the motion of any object must be measured in reference to something else, namely the reference point.

Are you saying that an object is never in motion if it doesn't have some type of reference? That's like saying, an object without light reflecting off of it is not there.

Although, if the universe was truly infinite in space, then I suppose you would need a reference point, but that's a different subject.

 

[isly ilwott]

Are you saying that an object is never in motion if it doesn't have some type of reference? That's like saying, an object without light reflecting off of it is not there.

No. I'm saying that in order to measure the motion, there has to be a reference point.

Although, if the universe was truly infinite in space, then I suppose you would need a reference point, but that's a different subject.

I think that regardless of the limits on the volume of space involved, there has to be a reference point to quantify the motion (change in position of the moving object relative to the reference point).

 

[MeJennifer]

No. I'm saying that in order to measure the motion, there has to be a reference point.

Simply untrue.

If you and I are in empty space and we send light signals to each other we can easily determine the amount of motion between us. There would be no need for frames or coordinate systems just the relativistic doppler formula.

 

[epkid08]

No. I'm saying that in order to measure the motion, there has to be a reference point.

Given that the universe is spatially finite, you will always know that traveling in a direction will cause motion.

Given that the universe is spatially infinite, you will not be able to distinguish, given no reference point, whether or not you hold a motion.

 

[peter0302]

This seems like it would have multiple applications for various preserving/maturing things i.e. foods, alcohol in our world.

Sure. Remember though that accelerating something to relativistic speeds requires a LOT of energy! So wouldn't it be a lot cheaper to freeze the food than to slow down it's clock by sending it around the Earth at .99c? :)

As for maturing things like alcohol - no, that's where you've lost me. You can slow the aging of something you send out at relativistic speeds. You can't accelerate its aging.

Has anyone seen this before? Is it correct? Is it applied in our world today?

Most certainly it is not applied. The only real world application of time dilation I am aware of is in the GPS system which does have to account for it because of the required precision. But I've never heard of a practical application of slowing an object's aging.

Also a question that is not about this topic.
Theoretically, if an object is motionless in a vacuum with 0 forces acting on it, does it experience time? Apparently, most people view time as a philosophical thing more than anything, but furthermore a consequence of motion. So my question is just that, is time just a consequence of motion?

Time is a consequence of change of any kind. Could the universe change in any wya if there was no motion? It is difficult to imagine it could. The fundamental particles don't change their properties without some kind of motion accompanying that change (i.e. an electron/positron can't become two photons without some kind of motion). So I'd have to say you're rigth, in your hypothetical there is no concept of time.

 

[epkid08]

As for maturing things like alcohol - no, that's where you've lost me. You can slow the aging of something you send out at relativistic speeds. You can't accelerate its aging.

Space beer! I'm sure sending beer into space so it matures faster is very cheap and efficient!

 

[isly ilwott]

Simply untrue.

If you and I are in empty space and we send light signals to each other we can easily determine the amount of motion between us. There would be no need for frames or coordinate systems just the relativistic doppler formula.

But you are still measuring my motion relative to yourself. I am measuring your motion relative to myself. Each of us has a different reference point...our own position.

 

[epkid08]

But you are still measuring my motion relative to yourself. I am measuring your motion relative to myself. Each of us has a different reference point...our own position.

The way I see it, there are two types of motion, relative and proper. Relative motion means you have a stationary reference point in which you measure your motion relative to. On the other hand, you can define proper motion as a simple distance divided by time scenario, which really boils down to a reference point at all ends of the universe. And of course, given that you have defined a finite universe, you will always be able to calculate a proper motion.

 

[matheinste]

Hello epkid08 and isly ilwott.

Empty space, or flat Minkowski space,the sort that SR deals with has no built in, natural reference point. We can of course measure things with reference to ourself or some other material body, letting a coordinate system to be built upon it to which we refer events, but we have no way of knowing or determining whether an inertial frame, that is an unaccelerated frame, is moving or stationary. If two objects are moving relative to each other we can at our convenience choose either or neither be stationary.

I believe the same is true of GR as regards reference points but i know very little of that subject.

Matheinste.

 

[epkid08]

Hello epkid08 and isly ilwott.

Empty space, or flat Minkowski space,the sort that SR deals with has no built in, natural reference point. We can of course measure things with reference to ourself or some other material body, letting a coordinate system to be built upon it to which we refer events, but we have no way of knowing or determining whether an inertial frame, that is an unaccelerated frame, is moving or stationary. If two objects are moving relative to each other we can at our convenience choose either or neither be stationary.

I believe the same is true of GR as regards reference points but i know very little of that subject.

Matheinste.

True, I was trying to explain to isly that you can easily define motion as a change in distance, but furthermore that an object will never be in absolute zero motion.

 

[matheinste]

Hello epkid08.

Motion is distance traveled usually with time as a parameter. However you have to measure distance. To do this you need some sort of distance measuring device. But who is to say that the measuring device is not moving and that which is being measured is motionless or vice versa. All motion is relative. You cannot say you are moving ( inertially ) or not, you can only say that you are moving relative to something else. This is absolutely fundamental to SR.

Matheinste.

 

[isly ilwott]

The way I see it, there are two types of motion, relative and proper. Relative motion means you have a stationary reference point in which you measure your motion relative to. On the other hand, you can define proper motion as a simple distance divided by time scenario, which really boils down to a reference point at all ends of the universe. And of course, given that you have defined a finite universe, you will always be able to calculate a proper motion.

You still have a reference point...being the position of the object at the time the measurement began.

 

[isly ilwott]

True, I was trying to explain to isly that you can easily define motion as a change in distance, but furthermore that an object will never be in absolute zero motion.

Motion is nothing more than a change in position. It does not have to involve a change in distance. A spinning sphere is in motion though it's center may be stationary and you may not be able to detect the motion without studying the surface. If there are no imperfections in a polished sphere with a single color finish, you would be hard put to detect the spinning motion...but the sphere is still moving.

Please be more correct when trying to explain things to me.

 

[dkgolfer16]

Space beer! I'm sure sending beer into space so it matures faster is very cheap and efficient!

I think you are very confused. Sending the beer into space at some fraction of c would cause it to age slower...

 

[MeJennifer]

Motion is nothing more than a change in position.

Under relativity this statement absolutely makes no sense, there are no positions. Motion is simply a change in distance.

A spinning sphere is in motion though it's center may be stationary and you may not be able to detect the motion without studying the surface.

You perhaps mistake motion with acceleration. Each point on a spinning ball, except for the center is accelerating and all points are in motion with respect to each other. However this motion is only significant at relativistic speeds.

 

[isly ilwott]

Under relativity this statement absolutely makes no sense, there are no positions. Motion is simply a change in distance.


You perhaps mistake motion with acceleration. Each point on a spinning ball, except for the center is accelerating and all points are in motion with respect to each other. However this motion is only significant at relativistic speeds.

Bullfeathers!

I am quite familiar with angular acceleration. As each point within and on the surface of the sphere is accelerated toward the axis of rotation, it experiences curvilinear motion...of a circular pattern.

Curvilinear motion involves changes in distance of any non-center point (or molecule, if you will) from it's previous position...regardless of the non-zero angular velocity.

By the way, two distinct points anywhere within a spinning sphere are not in motion relative to each other, even though they are both in cyclical motion relative to a fixed point outside of the sphere.

 

[MeJennifer]

I am quite familiar with angular acceleration. As each point within and on the surface of the sphere is accelerated toward the axis of rotation, it experiences curvilinear motion...of a circular pattern.

Ok so we do not seem to disagree on that one.

Curvilinear motion involves changes in distance of any non-center point (or molecule, if you will) from it's previous position...regardless of the non-zero angular velocity.

You are ignoring the principles of relativity again. Remember motion is always relative in relativity!

By the way, two distinct points anywhere within a spinning sphere are not in motion relative to each other, even though they are both in cyclical motion relative to a fixed point outside of the sphere.

It seems that you understand that motion is relative as you write now: "motion relative to a fixed point outside of the sphere"! However you are mistaken about the first part, all the points except for the center are in motion with respect to each other. You might want to consult the literature about relativity and rotating disks or balls.

By the way, I presume you mean a ball instead of a sphere as a sphere does not even have a center.