Question about time and measurement

  • #26
I can comprehend what is being said to me.
I think what is happening is I am not asking the question in the proper way.
And the question has changed as you have taught me more about how time dilation works.

So, an easy reference would be "earth time" which is 1 second per earth second in my question.
But if we were to be going 65% c (is this how we represent the speed of light?) we would be experiencing time as for every 5 earth seconds we feel 1 second. ( i dont know the math)
It seems that as you reach close to the speed of light ( this is my interpretation) that the discrepancy between what we perceive as time traveling fast, and what our original resting frame of perceived time, is a big difference.

But it doesn't work like this in the opposite direction? I intuitively feel this doesn't follow a normal pattern of physics (but i know nothing)

It would seem that, if we were to place a clock somewhere in space, which to us is seemingly not moving at all
that the difference would be something like 1.0000000123 seconds per earth second get recorded.
This seems like a very small discrepancy.
It should be that we can decrease our velocity and inversely experience 5 seconds our time for every 1 earth second, and see everything slowly meander about.

Like Drakkith said, we could be perceived from another object to be experiencing extreme time dilation. Its all about perception and reference points.

But obviously if we cant make something "rest" enough where it ages a considerable amount,while we experience 1 second per second does this imply a resting velocity? or inertia maybe is the right word?
This dimension has inertia built into it for a resting object to experience such a small discrepancy between units of time between a resting speed and a fast orbiting speed.

In many scenarios it is suggested that you could rip about in a spaceship for 5 years at an incredibly fast rate and return to earth to see that they have aged 20 years. Is this wrong? not the math I have said because I honestly have no idea, but the concept in general?

It almost sounds like it is easier to slow time down by traveling incredibly fast, than to speed time up by traveling incredibly slow.

I don't know how much science fiction I read has any credibility to it at all, but could high density electromagnetism shield an object from inertia and cause it to age to infinity?
maybe forget this last question....
 
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  • #27
Im going to move this to a new thread to try an get more responses.
So Drakkith and Harrylin if you are still interested in guiding me in this question please refer to the link that says
"Inertia and resting time rate"
 
  • #28
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The motion of the particles that make up an object do not affect whether that object experiences time dilation. It is only the relative motion of the object as a whole.
Hang on! That's not true. If an object as a whole experiences time dilation, then the motion of each particle that makes up the object must undergo the same time dilation. Otherwise it would violate the postulate 'the laws of physics are the same for all observers'.
 
  • #29
Drakkith
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Hang on! That's not true. If an object as a whole experiences time dilation, then the motion of each particle that makes up the object must undergo the same time dilation. Otherwise it would violate the postulate 'the laws of physics are the same for all observers'.
Of course. I wasn't saying anything to contradict that.
 
  • #30
WannabeNewton
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Hang on! That's not true. If an object as a whole experiences time dilation, then the motion of each particle that makes up the object must undergo the same time dilation. Otherwise it would violate the postulate 'the laws of physics are the same for all observers'.
This is incorrect. The constituent fluid elements making up a macroscopic object need not have the same individual motions, by any means, as the macroscopic object, viewed relative to some inertial frame. Your last sentence has no relevance whatsoever to the rest of your claim.
 
  • #31
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This is incorrect. The constituent fluid elements making up a macroscopic object need not have the same individual motions, by any means, as the macroscopic object, viewed relative to some inertial frame. Your last sentence has no relevance whatsoever to the rest of your claim.
Take a concrete example. You and I are both traveling inertially at different velocities.

I see your clock's 'second hand' tick over a second, moving at a certain angular velocity. The elapsed time by my clock is different than 1 second, so you have a time dilation with respect to me.

Is it possible that I will not necessarily see the 'atoms' in your second hand move at the same angular velocity, or preserve their positions with respect to each other at any time? That would only be possible if the physical laws in your frame were different than mine.

Unless proportions within a macroscopic object are preserved, it does not make much sense to say that a macroscopic object has 'a' time dilation.
 
  • #32
WannabeNewton
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Unless proportions within a macroscopic object are preserved, it does not make much sense to say that a macroscopic object has 'a' time dilation.
This is exactly why your claim above is incorrect. If we represent an extended body by a congruence of time-like curves and have an external observer who intersects a curve in the congruence at a given event on the curve then the external observer can boost to the instantaneous inertial frame of the fluid element described by said curve and the time dilation factors will be attributed on this individual level. Your claim was "If an object as a whole experiences time dilation, then the motion of each particle that makes up the object must undergo the same time dilation.". If you are talking about extended bodies and bringing into the picture the constituent fluid elements then your first clause by itself makes no sense.

A simple example is given by representing a rigidly rotating disk of angular velocity ##\omega## by a congruence of time-like curves. In order to boost from a background global inertial frame to the instantaneous rest frame of each fluid element in the congruence simultaneously, one uses the gamma factor ##\gamma = \frac{1}{\sqrt{1 - \omega^2 r^2}}## which clearly is different for fluid elements situated at different ##r## on the disk.
 
  • #33
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In the 'ideal' rest frame, there is no relative motion of the components, thus the fictional 'center of mass' moves at a constant speed. In the 'real world' rest frame the component motion varies on a molecular/atomic level (even if only due to thermal energy) for extremely short durations. There would be a mean rate of time dilation with small fluctuations. These would be insignificant at small fractions of c. I won't speculate on the significance at high fractions of c.
 
  • #34
WannabeNewton
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There is no rest frame for an entire time-like congruence. One can go to the rest frame of a given fluid element in the congruence and in this frame i.e. relative to this fluid element, neighboring fluid elements can have both angular and radial velocity.
 
  • #35
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...
It would seem that, if we were to place a clock somewhere in space, which to us is seemingly not moving at all
that the difference would be something like 1.0000000123 seconds per earth second get recorded.
This seems like a very small discrepancy.
It should be that we can decrease our velocity and inversely experience 5 seconds our time for every 1 earth second, and see everything slowly meander about.
...
Two observers A and B with different speeds, do not see time dilation for the other. Clocks are frequencies, therefore they observe doppler (frequency) shifts, positive if approaching, negative if receding. It's similar to the changing pitch of a sound passing by. The aging (accumulation of time) for each clock can only be done by a comparison of the two at a common location, as was shown in post 5 by harrylin.

If you pass by another clock, decreasing your speed each time, the maximum length tick will occur when you stop next to it. You can't go any slower, i.e., moving clocks will run slower, but never faster. In your above example, the difference would be zero, the clock reads 1.00.
 
  • #36
Ok I need to catch up a bit,
This is a lot of information....to add.
So firstly, I cant argue because you guys sound like you really know your stuff, But I am going to argue anyways. My lack of understanding can allow this right now.

Phyti you are not correct, I do know that. The one thing that is very apparent is that you ONLY see time dilation of another person. not yourself.
But you are correct I think that there is a doppler effect when moving directly away or directly toward an object.
so, I just wanna tie in that it is mentioned a bunch in these science papers that, somehow, because light is affected by gravity, then so too is time effected by gravity, and at the center of a black hole time stops, and at the center of a white hole (big bang?)time speeds up.
So when we are looking at a star up in the sky and it is blinking, this is because of the doppler effect, because when it rotates one side moves towards you while the other one away, and in the middle it appears to shrink.
If I got something wrong here let me know.^^

So I mean, I cant be wrong. If we were to stop somethings momentum, it would age. lots.
All the writing says it.
I think what we are forgetting in all this, MAYBE, is that the sun is moving at:
"The sun takes 200 million years to orbit around the centre of the galaxy. It is located 26,ooo light years from the centre so its orbital circumference will be Pi x radius = 22/7 x 26,000 light years. Speed is expressed as distance per unit of time.

Hence, speed equals (22/7 x 26,000) light years per 200 million years. "

I got this off yahoo answers lol.

And I bet by the difference in time (if we could accurately compare clocks) would give us a speed in which our galaxy is moving.

U know.. on this level Einstein always said " when two objects are moving relative to each other, it is completely impossible for one object to tell who is moving. Both objects would assume they are standing still, and the other is moving. And both would be completely correct"

So if this whole thing I am talking about is even REAL, then couldn't we have our astronauts going in circles so they can meet up and compare clocks once in a blue moon?
If we weren't sure who was moving, the clock that counted way less units would definetly clear the fog.

Anyways, lets not forget my question is, can we slow something down to make it age drastically?
 
  • #37
Phyti I just understood what you are saying lol. But you are still wrong because the seeing of the doppler effect is the same as the seeing of the time dilation I think
 
  • #38
ghwellsjr
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Phyti I just understood what you are saying lol. But you are still wrong because the seeing of the doppler effect is the same as the seeing of the time dilation I think
No he's not. There is approximately a two-to-one ratio between the Doppler factor and the Time Dilation factor at high speeds. You can't see Time Dilation, it's the result of taking what you see (Doppler) and applying Einstein's convention and doing some calculations.
 
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  • #39
Well then does that make him right about his previous post? because I thought how it worked was, Jane on earth sees Adams clock in his spaceship ticking slow, but to adam his clock is ticking normally and Jane's clock is ticking fast. Does this not imply that you can see time dilation in another object?

In any case we need to make this scenario so that we are using giant magical hourglasses (magical because the sand falls down, and the hourglass grows and accumulates sand at the top) and where our two objects in reference meet up once in a while at the same momentum to compare who has the bigger hourglass.
 
  • #40
u know whats interesting while im sitting here pondering this im thinking, the speed of light is exactly the speed of time somehow. and because it is constant this is why we experience time dilation?
I said earlier that I do not understand how light and time are connected. and Drakkith said this doesnt even make sense.
But why is light mentioned so much?

Drakkith you say that to any observer that the speed of light is always c. but that would mean if you were traveling at 80% the speed of light then the light you are seeing would have to be traveling at 180% of the speed of light for you to view it normally.
 
  • #41
Drakkith
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Phyti you are not correct, I do know that. The one thing that is very apparent is that you ONLY see time dilation of another person. not yourself.
But you are correct I think that there is a doppler effect when moving directly away or directly toward an object.
Of course. You must account for the doppler factor in order to propertly account for time dilation.

so, I just wanna tie in that it is mentioned a bunch in these science papers that, somehow, because light is affected by gravity, then so too is time effected by gravity, and at the center of a black hole time stops, and at the center of a white hole (big bang?)time speeds up.
First, you are correct that gravity affects time. But be aware that what happens beyond the event horizon of a black hole is unknown. Most scientists don't believe there is actually a physical singularity at the center, instead believing that we simply don't know how physics works at such an extreme scale. Also, I don't think time speeds up in a white hole, but I'm not sure. Either way, one has never been observed and I don't think most people believe they actually exist.

So when we are looking at a star up in the sky and it is blinking, this is because of the doppler effect, because when it rotates one side moves towards you while the other one away, and in the middle it appears to shrink.
If I got something wrong here let me know.^^
Blinking? I don't know what you're getting at. If you are referring to the "twinkling" of stars in the sky, that's simply because of the light passing through layers of air with different densities. Also, rotating stars do not appear "shrunk", they are actually stretched out into an ellipsoidal shape from their rotation.

So I mean, I cant be wrong. If we were to stop somethings momentum, it would age. lots.
All the writing says it.
No, it does not. It says nothing of the sort. It says that objects with a velocity of zero compared to you does not experience any time dilation due to relative motion as viewed from your frame of reference. Another frame of reference may be moving relative to the first one and would indeed see time dilation for both of you.

And I bet by the difference in time (if we could accurately compare clocks) would give us a speed in which our galaxy is moving.
Moving compared to what? You need something to compare the overall frame of the galaxy against. One of the best frames, but by no means the only frame, is one at rest relative to the CMB.

U know.. on this level Einstein always said " when two objects are moving relative to each other, it is completely impossible for one object to tell who is moving. Both objects would assume they are standing still, and the other is moving. And both would be completely correct"

So if this whole thing I am talking about is even REAL, then couldn't we have our astronauts going in circles so they can meet up and compare clocks once in a blue moon?
If we weren't sure who was moving, the clock that counted way less units would definetly clear the fog.
Ah, but you are missing a very important point here. In your situation you do NOT have inertial frames of reference. One has been accelerating, and in that case the rules are different.

Anyways, lets not forget my question is, can we slow something down to make it age drastically?
For the last time, no. It cannot be done.

u know whats interesting while im sitting here pondering this im thinking, the speed of light is exactly the speed of time somehow. and because it is constant this is why we experience time dilation?
I said earlier that I do not understand how light and time are connected. and Drakkith said this doesnt even make sense.
But why is light mentioned so much?
Light, AKA an electromagnetic wave propagating through space, is irrelevant. It is the SPEED of light in a vacuum that is the key. You could say that there happens to be a maximum speed limit in the universe and that light happens to travel at this speed because it is massless. But light itself, as an EM wave, has no connection with time. Sorry if I confused you.

Drakkith you say that to any observer that the speed of light is always c. but that would mean if you were traveling at 80% the speed of light then the light you are seeing would have to be traveling at 180% of the speed of light for you to view it normally.
80% compared to what? That's what you need to start thinking about. You MUST consider two frames of reference if you want to really grasp this. Trying to think about SR and time dilation using only 1 frame will NOT work. You have to say 80% c in relation to another frame and then look at what both frames will see and calculate.
Read this: http://en.wikipedia.org/wiki/Time_d...nce_of_time_dilation_due_to_relative_velocity
 
  • #42
Of course. You must account for the doppler factor in order to propertly account for time dilation.



First, you are correct that gravity affects time. But be aware that what happens beyond the event horizon of a black hole is unknown. Most scientists don't believe there is actually a physical singularity at the center, instead believing that we simply don't know how physics works at such an extreme scale. Also, I don't think time speeds up in a white hole, but I'm not sure. Either way, one has never been observed and I don't think most people believe they actually exist.



Blinking? I don't know what you're getting at. If you are referring to the "twinkling" of stars in the sky, that's simply because of the light passing through layers of air with different densities. Also, rotating stars do not appear "shrunk", they are actually stretched out into an ellipsoidal shape from their rotation.
When I say blinking I mean one side is red and one side is blue spectrum because of the doppler effect. When I say shrunk I meant just in the middle because when viewing an object in motion this object appears to shrink, but it shrinks so uniformly that if you were inside the object nothing would change inside to you but the world outside would stretch.



No, it does not. It says nothing of the sort. It says that objects with a velocity of zero compared to you does not experience any time dilation due to relative motion as viewed from your frame of reference. Another frame of reference may be moving relative to the first one and would indeed see time dilation for both of you.
Objects at 0 would, by the pattern we are following , experience an infinite amount of time accumulation I think.
and objects at the speed of light do not experience time.
If a photon were sentient and were in a universe of mirrors that ended in a brick wall, the photon would experience hitting all the mirrors and the brick wall simultaneously at the speed of reality.
To us at earth momentum this photon would take X amount of time to travel this distance. A very long time. Lets not forget that it takes light 1.03 seconds to reach the moon from us and 8 mins to reach the sun. at earth speed.



Moving compared to what? You need something to compare the overall frame of the galaxy against. One of the best frames, but by no means the only frame, is one at rest relative to the CMB.
I am not sure what you mean by the CMB.
but What would you consider at rest?
our solar system is traveling around the galaxy at an extremely fast rate. We put our hourglass "at rest" behind our earth orbit, go all the way around the sun, and pick it up on the other side, we will see that this clock has experienced 1.00034 seconds for every earth seconds.
But don't forget its traveling at the speed our solar system is going.
This is not at rest.
We would have to leave any warp in space time that would drag us along, and really stop moving.
If our galaxy were moving it would probably appear to zoom away from us if we were at rest.

Ah, but you are missing a very important point here. In your situation you do NOT have inertial frames of reference. One has been accelerating, and in that case the rules are different.
what you are saying here is exactly why you believe that when we drop something off in space, but still in our solar system, it appears to be at rest.

For the last time, no. It cannot be done.
I get that you don't have an inertial frame of reference if you werent accelerating or slowing down.
But close to the speed of light, or maybe not even that close, light is warped,stretched and curved because you are seeing it travel slower.
And i really believe if we had a clock that counted time accumulation rather than a continuous cycle from 1-12, we would be able to compare time accumulation between different momentums
and figure out how fast it is moving compared to a rest point.


Light, AKA an electromagnetic wave propagating through space, is irrelevant. It is the SPEED of light in a vacuum that is the key. You could say that there happens to be a maximum speed limit in the universe and that light happens to travel at this speed because it is massless. But light itself, as an EM wave, has no connection with time. Sorry if I confused you.
Yet it has the connection to time where if you were to reach the speed of light time would stop for you? and at close to the speed of light everything around you ages huge while you feel nothing different than one second per second?
I feel like you don't think I am understanding basic principles about how light slows down when it is passing through a medium, etc. I have read that we can bring sodium gas to close to absolute zero and light will be going only a few miles per hour through this medium.
The questions I am asking are really about momentum and time.
electromagnetic wave speed just happens to be the universal speed limit. for time as well. right?

If we follow the pattern, then at rest you should experience infinite time accumulation.


80% compared to what? That's what you need to start thinking about. You MUST consider two frames of reference if you want to really grasp this. Trying to think about SR and time dilation using only 1 frame will NOT work. You have to say 80% c in relation to another frame and then look at what both frames will see and calculate.
Read this: http://en.wikipedia.org/wiki/Time_d...nce_of_time_dilation_due_to_relative_velocity
K man. when I say 80% of c i mean compared to 100% of c.....if you are traveling at 80% of what the max speed is, how much time would you accumulate compared to what we accumulate on an average day here on earth.
There is always a frame of reference that I am using and I don't understand why you keep saying compared to what?
You cant truly believe that at "rest" a clock will only experience slightly over 1 second per earth second.
So going fast we can easily explain away that a fast person may only experience 1 second for every 10 seconds an earth person feels.
But you cant believe that a slow person could experience 10 seconds for every 1 second and earth person feels.
Why would the pattern stop?
Using time accumulation compared to 1 second per earth second, we should be able to compare something that we can gauge the age of if left alone, and use math to figure out how much slower it would need to go to be at rest

the faster you go the slower time goes, the slower you go the faster time goes.
 
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  • #43
It cant be true that time goes slower the closer you get to the speed of light, but does not speed up the farther away from the speed of light you get.
 
  • #44
Drakkith
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I'm sorry, but you simply don't understand the basic principles of Special Relativity and I don't think I can explain them to you. If you truly would like to understand then there are plenty of resources online. You can even read Einstein's original paper on SR. Everything is explained.
 
  • #45
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Furthermore if i made a bar of copper+entangled duplicate, sent one with the clock, then put an electrical current through the one I kept with me, what would happen to the spaceship copper?
Does this create entangled electrons from a spooky distance?
Why would the electrons introduced by the current get entangled to the distant copper bar? The electrons from the current are not necessarily entangled with anything, so no, it wouldn't create entangled electrons "from a spooky distance."
 
  • #46
yah i was told this about 60 posts ago BMW but thanks
what we are talking about in this thread is much different
 
  • #47
ghwellsjr
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Well then does that make him right about his previous post? because I thought how it worked was, Jane on earth sees Adams clock in his spaceship ticking slow, but to adam his clock is ticking normally and Jane's clock is ticking fast. Does this not imply that you can see time dilation in another object?
I don't see anything wrong with phyti's previous post (#35). As I mentioned, the Doppler factor can be close to double the Time Dilation factor when objects are receding from each other and as they are approaching each other, the inverses apply. So as an object approaches and passes an observer, its observed Doppler factor will start high (positive, as phyti says) and end up low (negative as phyti says) which means at some point it will be equal to the Time Dilation factor for the rest frame of the observer. If the object is in "orbit" around the observer, maintaining a constant distance from him, the Doppler factor is equal to the value of the Time Dilation factor in the inertial rest frame of the observer but in other inertial rest frames they are not equal. As I keep saying, Time Dilation is a frame dependent effect and observers can't know what frame you are choosing to put them in. The Doppler factor is not frame dependent and is the same no matter what frame you use to describe a scenario.

In any case we need to make this scenario so that we are using giant magical hourglasses (magical because the sand falls down, and the hourglass grows and accumulates sand at the top) and where our two objects in reference meet up once in a while at the same momentum to compare who has the bigger hourglass.
What is magical about an hourglass in which the sand falls down? Or is it magical because it works in the absence of gravity the same as it would on the surface of the earth?
 
  • #48
Yeah I mean magical because of the absence of gravity.

I have found yet another conundrum with this theory.
I was using a time dilation calculator and found out that moving at 98.4% the speed of light you will experience a time dilation difference of 2.7 seconds. meaning that you just counted one second, but a "stationary object" ( this is the word the calculator used) experiences 2.7 seconds.
The other time dilation calculator I used came up with a much different answer.0.10903 seconds pass at this speed for every 1 second for a stationary object.

K fine, but heres whats weird with that.

at the speed of light time stops? this means that a photon could travel in one direction for infinity years and never experience one second pass.
Don't u think that at 99% of the speed of light time would barely barely be passing at all?

Instead we see that it passes 1/3 as fast or 1/10 as fast?
Is there some exponential loss of time accumulation after 99%?

It seems like either time dilation must be much more extreme than our math allows
Or to stop time we would have to be going much faster than the speed of light.
 
  • #49
Drakkith
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Yeah I mean magical because of the absence of gravity.

I have found yet another conundrum with this theory.
I was using a time dilation calculator and found out that moving at 98.4% the speed of light you will experience a time dilation difference of 2.7 seconds. meaning that you just counted one second, but a "stationary object" ( this is the word the calculator used) experiences 2.7 seconds.
The other time dilation calculator I used came up with a much different answer.0.10903 seconds pass at this speed for every 1 second for a stationary object.
Yes, because you are traveling, with respect to that frame, at 98.4% c, and thus are time dilated.

at the speed of light time stops? this means that a photon could travel in one direction for infinity years and never experience one second pass.
Trying to imagine what time is like at c is pointless. Our math does not allow us to set a frame of reference at c, and thus we cannot try to make predictions about what will happen. Any answer would be pure guesswork/speculation. If you really want to, feel free to imagine that time stops at c. It makes no difference.

Don't u think that at 99% of the speed of light time would barely barely be passing at all?

Instead we see that it passes 1/3 as fast or 1/10 as fast?
Is there some exponential loss of time accumulation after 99%?
Here's the graph:

480px-Time_dilation.svg.png


As you can see, the amount of time dilation (the Y axis) increases rapidly when we get very close to c. (X axis is in fractions of c)
 
  • #50
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lets not forget my question is, can we slow something down to make it age drastically?
No. The slowest it can go is 0, and then it ages normally.
 
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