Relativity and Time

[TheBaker]

I'm doing a project on Time Travel and I'm currently looking at time dilation. I'm interested in finding out exactly to what extent time is dilated in certain circumstances. I know that the time dilation due to observer velocity can be calculated as follows:

 

t' = t / (1 - (v^2 / c^2))^0.5

 

But what is the equation to calculate time dilation due to distance from a mass (gravity)?

 

And how do you combine the two effects? Can you just add together the two time dilations?

 

Also, with regards to the time dilation of someone in orbit around the Earth, do you use their absolute orbit speed? Or do you need to adjust it to take into account the fact that the Earth is rotating on its own axis?

 

Thanks.

[CraigD]

But what is the equation to calculate time dilation due to distance from a mass (gravity)?

[math]t^{\prime} = t \sqrt{1-\frac{r_0}r}[/math]

, where [math]r[/math] is the distance from the mass, and [math]r_0[/math] is the mass’s Schwarzschild Radius - the size its event horizon would be if it were a black hole.

And how do you combine the two effects?

You multiply the two time dilation factors.

 

Information like this is available in common reference sources, such as the wikipedia article “time dilation”.

[TheBaker]

Thanks. I did look on the Wikipedia page, but the wealth of equations and informations just boggled my mind!

[kalesh]

Hi,

I am not sure you want to hear this as its not from mainstream science.

I have a theory of time dilation that can be used for time travel. If you want let me know and I'll post a brief outline for you to pondfer on.

[TheBaker]

I know that you can use time dilation to travel forwards in time (by effectively slowing time down for everyone else), but I'd be particularly interested if you have a theory that would let you travel backwards in time. Regardless though, please post your theory.

[arkain101]

What I gather is that there is only a change in the rate of aging or entropy, no time travel?

[kalesh]

Please note this isn't from mainstream science.Also it doesn't exactly give the means to time travel. But it does say what the next step should be. Someday I'll post the full version of the theory and see what the reaction of members here is.

Ok here goes.

According to this theory time never actually slows down or speeds up. What actually happens is that the person speeds up. Also this theory assumes that time makes a fourth dimension of spacetime. Imagine a spacecraft travelling at a 10m/second(so there is virtually no time dilation). Lets define its velocity components. Vspace=10m/s (velocity in dimension of space). Vtime=1second/second (velocity in dimension of time). Now it accelerates to 0.8c in the dimension of space. But because we cannot see and isolate the dimension of time when the force is applied in the direction of motion. he force is applied in both the dimension of space and time. So it not only speeds up in velocity in dimension of space (Vspace) but also in velocity in dimension of time (Vtime). upon calculation Vspace=0.8c and Vtime=1.6seconds/second.

Once you digest the above think about this.

If the force is only applied in direction of travel in dimension of space instead of in direction of travel in both space and time only Vspace will increase and not Vtime (no more time dilation).

 

Now comes the interesting part.

If you apply force against the direction of movement in dimension of time only time will slow down.(opposite effect of time dilation) Upon application of enough force time will stop and as you continue to apply force time will start moving in reverse. And you got your time machine.

 

Now as to how we can apply force in dimension of time without applying it in dimension of space is what I have been unable to figure out.

Someone figure it out quick. I wanna make a time machine:D

 

No seriously if you read and understand what I am trying to say with an open mind it can be done.

[Qfwfq]

According to this theory time never actually slows down or speeds up. What actually happens is that the person speeds up.

Indeed time doesn't slow down. It doesn't really make sense to say this. Neither does the person speed up.

 

Time dilatation is just a matter of different observers using different coordinates.

[Farsight]

If you apply force against the direction of movement in dimension of time only time will slow down.(opposite effect of time dilation) Upon application of enough force time will stop and as you continue to apply force time will start moving in reverse. And you got your time machine...

 

Sorry kalesh. But time is only a counting direction, not a real direction. We have no freedom of movement in time. You can take a pace to one side and move a metre in space, but you can't step back a second. Or forward. We cannot move in the "time" dimension, because it's only a measure, and whilst this makes it a "dimension" it doesn't make it a real Dimension like the Dimensions of space. You cannot apply any force to this "movement" because there isn't any. That's why there are no time machines, and never will be. Sorry, but time machines are fiction. More details here:

 

http://hypography.com/forums/physics-mathematics/9504-time-explained-v2-1-a.html

[kalesh]

Thanks for your comments but I really wont be disscussing it right now. I just posted this for analysis by TheBaker. I'm sorry I wont be disscussing this here in detail. I still have some things to figure out and when I have done so I will post it in a new thread for open disscussion.

This is a brief summary and does not contain all the info.

The full covers questions such as:

Why is the speed of light constant?

Why can we see space but not time?

Why the time dimension is a real dimension?

How making time 3 dimensional (so spacetime is 6D) the "parrallel worlds theory" is absorded into this theory.

Properties of gravity and its effect on time.

And a host of other things.

[HydrogenBond]

Distance is only 3-D due to convention. The convention is actually for location instead of distance. Picture if one has a cube 1 unit per side. The diagonal distance is the square root of 3 or 1.7. If one was traveling along the diagonal at 1.7 units/sec it would take one second, from apex to apex. But if you measure the disances traveled in all three dimensions, one has gained 1 unit in x, 1 unit in y and 1 unit in z, or three units instead of 1.7. In other words, the 3-D space convention is for location in distance and not for pure distance. To get pure distance from a 3-D location convention one has to massage this system with a little algebra.

 

We could have defined time in a 3-D coordinate system so we could measure the amount of time in x, the amount of time in y and the amount of time in z. In the case of the example, the total time is 1 second. So it spent one second in x, y, and z at the same time.

 

If you look at the speed of light and our conventional 3-D distance cube of space, if it traveled along the diagonal from apex to apex, the speed of light is not violated only if distance is defined as the 1-D diagonal. It you make distance 3-D it would have to exceed the speed of light to travel 3 units of distance, 1 in each of three directions.

 

There is a difference between convention and reality. One assumes we live in a 4-D universe, with three distance dimensions and one time. But energy only lives in 2-D with only one distance and one time.

[The_Right_Stuff]

Sorry kalesh. But time is only a counting direction, not a real direction. We have no freedom of movement in time. You can take a pace to one side and move a metre in space, but you can't step back a second. Or forward. We cannot move in the "time" dimension, because it's only a measure, and whilst this makes it a "dimension" it doesn't make it a real Dimension like the Dimensions of space. You cannot apply any force to this "movement" because there isn't any. That's why there are no time machines, and never will be. Sorry, but time machines are fiction. More details here:

 

I disagree.

 

If one assumes that all objects in Space-Time are constantly in motion, and that the magnitude of that constant motion is the same as the speed light has across space, then all the pieces fall together.

 

If this is the case, then all that can be done to any object present within Space-Time, is change the direction of its constant motion across that open Space-Time.

 

If an object is at rest in Space, then its entire motion is across Time. If its entire motion is directed across Space, then it is at rest in Time.

 

If an object is at rest in space, the object extends across Space only. However, if you change the direction in Space-Time in which the object is traveling, then the object is also being rotated in Space-Time which also means that the object begins to extend across the dimension of Time, and now extends less across the dimension of Space.

 

If one performs a geometric analysis of such a four dimensional structure of Space-Time, along with all matter being constantly on the move within it, it produces equations that are identical to the Lorentz-Fitzgerald Contraction equation, the Time Dilation equation, the Lorentz Transformation equations, and the Velocity addition equation.

 

. . .TIME

. . ..( L )

._____

... . .^. ..

.. . . .|. . .. . ..

.. . . .|. . .. . . . ..

.. . . .|. . . . . . . . ..

.. . . .|. . . . .. . . . . ..

.. . . .|. . . . . . . . . . . .. .( L' )

.. . . .|.. . . . . . . . . . . .

.. . . .|.. . . . . . . . . . ... ..

.. . . .|.. . . . . . . . . . .... ..

.. . . .|==========>----> . .SPACE

. . . . . . . . .( v )

 

In the vector diagram above, if the object, say a train, is at rest in Space, then its entire length ( L ) extends across Space, and its entire constant movement is across Time ( t ).

 

If the objects direction of travel is altered such that it now has the velocity ( v ) across Space, the object now partially extends across Time and extends less across space than previously such that its new spatial length becomes ( L' ).

 

It is also to be noted that the back end of the Train is ahead in Time, and the front end is behind in Time. If this Train was 75,000 km long when at rest in space, then it were in motion across space at 260,000 km per second, based on the above geometry, it would then be reduced to 1/2 of its previous spatial length. Also, at this spatial velocity, the Train would extend across the dimension of time by a total of approx. 0.2165 of a second, and any clocks onboard the Train would now also be ticking at half speed ( t' ). A clock positioned at the back end of the Train would be ahead of a clock positioned at the front end of the Train by that 0.2165 of a second.

 

If we were to send light from the back end of the Train to the front, it would take approx. 0.933 of a second for the light to complete the trip due to the velocity of the light relative to the Train being ( c - v = 300,000 - 260,000 = 40,000 km per sec. ), and the Train spatial length having reduced to from 75,000 km ( L ) to 37,500 km ( L' ). If the light were sent in the opposite direction, it would take approx. 0.066 of a second for the light to complete the trip due to the velocity of the light relative to the Train being ( c + v = 300,000 + 260,000 = 560,000 km per sec. ) in combination with the Trains new length ( L' ).

 

Now as previously stated, the clocks onboard the Train are ticking at half speed, and so, the 0.933 sec. time period will be measured as a 0.4665 sec. time period, and the 0.066 sec. time period will be measured as a 0.033 sec. time period. Now since the clock at the rear of the Train is ahead by 0.2165 sec., this also means that the clock at the front of the Train is behind the clock at the rear end of the Train by 0.2165 of a second.

 

And so, if the light at the rear end of the Train lit up at 0:00, and the clocks were previously synchronized when the train was at rest on the tracks, then at that same moment the clock at the front of the Train will read -0:00.2165 . Therefore if the 0.4665 time period of the light moving from the rear end of the Train to the front is measured at the front end of the Train, then the outcome would be ( 0.4665 sec. + (-0.2165 sec.) = 0.25 sec. ), which equals a 0:00.25 clock reading.

 

If the light was sent in the opposite direction, and the light at the front end of the Train lit up at 0:00, then at that same moment the clock at the rear of the Train will read +0:00.2165 . Therefore if the 0.033 sec. time period time period of the light moving from the front end of the Train to the rear is measured at the rear of the Train, then the outcome would be ( 0.033 sec. + 0.2165 sec. = 0.25 sec. ), which equals a 0:00.25 clock reading.

 

And so in both cases it appears to those onboard the train as though light has traveled from one end of the train to the other in either direction in 0.25 of a second, meaning at the expected speed of light. ( 75,000 km / 0.25 sec. = 300,000 km per sec.).

 

Meanwhile, the speed of light relative to space, is always c.

 

Thinking four dimensionally, one realizes that the axis of a spinning object begins to extend across both Space and Time as the result of the objects change in the direction of it's constant motion across Space-Time, and that this will reduce the objects spatial angular velocity due to part of the complete rotation now being across the dimension of time as well, and therefore less across space.

 

And so if that spinning object throws off a Photon, then because of the axis is no longer only a spatial axis but extending across Time and less across space, the Photon will be thrown at a slower speed across Space, and at a speed that is slower by the equal amount of the object's new measure of motion across space. The release speed of the photon becomes ( c - v ) rather than c. The final spatial speed of the Photon then becomes (( c - v ) + v ) with v being the spatial velocity of the object that had released the photon. In the opposite direction, the opposite occurs. It becomes (( c + v ) - v )).

 

The outcome, relative to space, is the the speed of light always turns out to be ( c ).

 

And there you have it !

 

Due to the geometry being what it is, there is no true way to determine whether or not you are at rest in space, and with this geometry and its effects upon measurements of space and time, you can also keep adding one velocity upon another, and all seems fine, but in actual fact your total velocity is still less than ( c ). Gee, that sounds familiar !

[Farsight]

I disagree. If one assumes that all objects in Space-Time are constantly in motion, and that the magnitude of that constant motion is the same as the speed light has across space, then all the pieces fall together...

 

Incorrectly in my view. IMHO your above assumption is wrong because we simply cannot move through time. I can take a step sideways to travel a metre in space, but I can not take a step backwards by one second. Time has no real length, it is a relative measure of motion through space, and the notion of motion through time itself is a cultural and mathematical artifice for which we have absolutely no physical evidence. Yes the seconds "pass by", yes we can travel fast or descend a gravity well to see them tick by more slowly, and yes we always measure c to be 300,000km/s. But there are no four dimensional structures and you just can't show me one. See TIME EXPLAINED for details, but perhaps we'll have to agree to differ.

 

http://hypography.com/forums/physics-mathematics/9504-time-explained-v2-

[The_Right_Stuff]

Incorrectly in my view.

 

Views often disagree with facts.

[Farsight]

Sure, like the fact of how you can move through time. Next time you rent a time machine, you can pop back to here and now and show me. And bring one of those four dimensional structures will you? Oooh, is that you at the door? Nope. I rest my case.

 

If nothing moved anywhere, there wouldn't be any time. There would be no collisions, no reactions, no light, no gravity, no events, nothing happening. Just a static timeless universe. But if something moved, then you've got some time. Because time is just a measure of motion, of change, compared to other motion and change. You can't move through the measure of motion. You can only move through space.

 

But anyhow. I presume you haven't read TIME EXPLAINED. So let's just agree to differ.

[Little Bang]

I disagree.

 

 

 

If an object is at rest in Space, then its entire motion is across Time. If its entire motion is directed across Space, then it is at rest in Time.

 

!

 

At rest with respect to what? Think about it, to go back in time by one second every proton, electron AND waveform in the universe would have to be returned to their position of one second ago. I suspect this would require a rather large some of energy.

[kalesh]

Incorrectly in my view. IMHO your above assumption is wrong because we simply cannot move through time.

 

Why can't you move through time? Just because backward time travel hasn't happened doesn't mean it can't.

 

I can take a step sideways to travel a metre in space, ......

 

Oh really? It may seem simple at first but imagine this.

You are in a body fitting spacesuit. There is empty space all around you for infinity. How do you take a step now? Even if you move a long distance you may still be at the same place because its empty and theres no reference.

 

.....See TIME EXPLAINED for details, but perhaps we'll have to agree to differ.

 

I have seen it but that doesn't mean that I agree to it.

 

 

 

Sure, like the fact of how you can move through time. Next time you rent a time machine, you can pop back to here and now and show me. And bring one of those four dimensional structures will you? Oooh, is that you at the door? Nope. I rest my case.

Even if I did you wouldn't see it.

 

If nothing moved anywhere, there wouldn't be any time. There would be no collisions, no reactions, no light, no gravity, no events, nothing happening. Just a static timeless universe. But if something moved, then you've got some time. Because time is just a measure of motion, of change, compared to other motion and change. You can't move through the measure of motion. You can only move through space.

 

But anyhow. I presume you haven't read TIME EXPLAINED. So let's just agree to differ.

 

See above

 

At rest with respect to what? Think about it, to go back in time by one second every proton, electron AND waveform in the universe would have to be returned to their position of one second ago. I suspect this would require a rather large some of energy.

 

Certainly not because if that happened than everyone would experience backward time at once. And that is not what is supposed to happen.