Physics Question Regarding the Nature of Time Dilation

I have a relatively decent grasp on various aspects of modern physics, but recently I have been baffled by actually delving into the "why" behind gravity, clocks, and time dilation. We all know that is is maintained that a gravitational field, or constant acceleration in free space since that provides the illusion of a gravitational field, will cause a clock to run slower than it would in a weaker gravitational field. Two of the most common examples are as follows:

A spaceship approaching the speed of light supposedly causes time to slow down immensely, moreso than a synchronized clock left on earth. And a clock placed near the surface of the earth will run more slowly than another stationary clock raised even a short distance more than the previous clock, since the earth's gravity is stronger the closer an object gets to the surface. Okay, this is all basic stuff, but here is where I cannot wrap my head around what is happening...

Time is not a physical thing, in that it has no mass, it cannot be seen, etc. It is basically a measurement that we use to make sense of things and to make things easier. A clock is nothing more than a physical device we developed to move at a steady rate. Being that a clock is a physical object, the movement of the hands, or the movement of the particles that keep this rate constant in more advanced clocks, are the things that are going to be affected by gravity.

So my question is how can it be determined that time is actually what is slowing down, considering that it cannot be freed from the physical constraints of the measuring device, ie whatever is causing the movement? Does that make sense? I could be missing something fundamental here, and I don't doubt that at all, but if not, wouldn't we need a clock that was not physically affected by gravity in this manner? As I was writing this I see where I may have gone wrong, but I am having trouble nonetheless. Hopefully someone understands what I am trying to say and am asking, knows where I have gone wrong, and can explain it in a way I can understand. That is a very tall order in my opinion, so I will not be upset if no one can provide me with the correct insight on the subject.

I tried searching both ATS and the web but my main problem is that I cannot develop a search term adequate enough to return the proper results. Surely there have been many other people who have been confused by this aspect of time, and have asked basically the same questions I have, but I cannot find anything addressing this particular issue. Any insight will be greatly appreciated, and I know there are a handful of very intelligent persons when it comes to physics on these forums, so hopefully one of them sees this and can understand and explain what I am attempting to get across.

Einstein addressed this originally I believe. Your statement about the speed of light. Michio Kaku seems to think Einstein may have been wrong. Try searching youtube for some of his lectures. I was watching one earlier tonight where he addressed this phenomenon, but I'm very tired right now and I don't think I could articulate it as well as Michio does. I will go as far as to say it seems the flow of time and gravity are somehow co-related.

reply to post by JiggyPotamus


Dear JiggyPotamus,

That is one of the best questions I have read on this site. Don't worry that you could not Google it, I am impressed that you even thought it. Let us ask some base questions. What is time, you say it is a measurement and agree. What is the proper measurement of time. Einstein argued that it was the movement of matter through space. Using that thought then time is relative to placement in relationship to other objects. There are societies that did not believe in time. I see time as being the changing of thoughts within a mind. A little metaphysical perhaps; but, the only way we experience time is in our minds. There is no way to measure my concept of time as it all takes place in our consciousness.

reply to post by JiggyPotamus


This is a very interesting question, and I think I know what you are trying to ask. A clock is a measuring device and being mechanical, it would be affected by gravity, but just because it is slowed down would it have an affect on our perception of time? Could it actually have the affect to slow down (for instance) the aging process,or does it only affect the clock?

I wish I could answer this, but even though I have a fascination in physics, my own college degree is in Website design/development.

It seems to me that time is just a measurement of the duration of physiscal events. So without any physical events, there would be no time. I don't see how time can exists without "physical constraints", by definition.

reply to post by JiggyPotamus


Relativity.

Everything is relative.

It's easy to get lost in the complexity of it, I often get lost in it, and it's an uncomfortable bewilderment.



It doesn't answer anything, but it provides an insight into how reality works.

Time to an external observer is different to the time of a thing being observed.

I read a book once that explained it somewhat.

What it said was that if you are traveling in the vacuum of space and you are moving at a force of 1G and you brake with the force of 1G, over a period of time you would experience the dilation.
For example: 5 years at those conditions would make 7 years pass on earth. For 25 years like 36 years would pass on earth and so on and so forth.

Barring the math I think this is about the simplest explanation.


Um,. . . Now I remember.

The name of the book was Chariots Of The Gods.

reply to post by JiggyPotamus


I too have wondered 'how could this be so'? I read about the prediction and tests as a young HS student and when I studied it in Physics while at college, no one explained it adequately for me to be satisfied I understood the mechanism. My suspicion is it is string theory issue. But for those who think even more outside the box than string theory, maybe time is a metaphysical event, where time is essentially a figment of our imagination that our spirits use to orient to earth. I wonder what would happen if we could test this theory on a much larger Jupiter/Saturn sized mass?

So my question is how can it be determined that time is actually what is slowing down, considering that it cannot be freed from the physical constraints of the measuring device, ie whatever is causing the movement?

Start here: What is speed? Distance over time. You have to measure that period of time (as well as the distance), right?

Now, no matter how fast you travel, if you measure the speed of light it will always be 299,792,458 m/s.

But what if you are traveling at 149,896,229 and you measure the speed of light. Let's say you do it by measuring how long it takes light to bounce between two mirrors on your space ship. The distance between those mirrors doesn't change but they are both moving at half the speed of light so it should take longer for the light to get to the forward mirror and less time for the light to get to the rearward mirror. But it doesn't. Because the distance hasn't changed, it means that time must have.

That's how Albert looked at it...more or less. Less actually. He used math and stuff.

This is a good question. Look here for the answer.
physics.stackexchange.com...
In special relativity there is no absolute frame of reference. In your examples when that spaceship approaches the speed of light, its mass approaches infinity. Let us say however for the sake of argument that the mass is not a factor. In that case time is equal for both the space ship and earth in their frame of references. Meaning as you start going faster you clocks don't slow down. These frames of references relative to each other move at different speeds in space-time.

reply to post by an0nThinker

Meaning as you start going faster you clocks don't slow down.

Actually, they do. But only from the point of view from someone outside your frame of reference.

Jiggy, you rock. Flagging this.

I am not a physicist. I worked with one, a long time ago, and we argued incessantly about this very same subject. Here was my argument:

Three space ships are in deep space, in different locations, at rest compared to each other. Two of them accelerate, while one remains still. All three ships have clocks mounted to the outside. Ship A accelerates to 99% light speed. Ship B accelerates to 50% of light-speed. Their acceleration, trajectory, and timing are all perfectly organized so that, when they stop accelerating, the time on the clocks will be exactly the same. they will pass within inches of each other at the exact same moment in time three hours after they finish accelerating. When the moment is reached, what time is it?

For ship A, Ship B is traveling at 50% light speed, and Ship C is travelling at 99% light speed. For ship B, Ship A is travelling at 50% light speed, and ship C is travelling at 50% light speed. For ship C, Ship A is at 99% light speed, and ship B is at 50% light speed. Given the time dilation of relative speed, depending on which ship observes the other, all three ships are at all three relative speeds, simultaneously. This is a paradox, and therefore there has to be a problem with the theory.

My solution was that time is a wave-like phenomenon which travels in a single direction three-dimensionally within a 4-dimensional frame of reference. Its progression through long strings of matter (not super-strings, but rather something that looks like, well, long strings) allows interaction between the particles, which generates our perception of time. The upshot of this idea is that time travel is not only possible, but probable. The downside is that, even if you could go back in time, everything would be either different, or at complete rest. But I digress.

Kudos to you for asking the question. I do not have an answer which would be accepted by more properly trained minds than my own. But I'll watch to see what their answer might be

Originally posted by JiggyPotamus
I have a relatively decent grasp on various aspects of modern physics, but recently I have been baffled by actually delving into the "why" behind gravity, clocks, and time dilation. We all know that is is maintained that a gravitational field, or constant acceleration in free space since that provides the illusion of a gravitational field, will cause a clock to run slower than it would in a weaker gravitational field. Two of the most common examples are as follows:

A spaceship approaching the speed of light supposedly causes time to slow down immensely, moreso than a synchronized clock left on earth. And a clock placed near the surface of the earth will run more slowly than another stationary clock raised even a short distance more than the previous clock, since the earth's gravity is stronger the closer an object gets to the surface. Okay, this is all basic stuff, but here is where I cannot wrap my head around what is happening...

Time is not a physical thing, in that it has no mass, it cannot be seen, etc. It is basically a measurement that we use to make sense of things and to make things easier. A clock is nothing more than a physical device we developed to move at a steady rate. Being that a clock is a physical object, the movement of the hands, or the movement of the particles that keep this rate constant in more advanced clocks, are the things that are going to be affected by gravity.

So my question is how can it be determined that time is actually what is slowing down, considering that it cannot be freed from the physical constraints of the measuring device, ie whatever is causing the movement? Does that make sense? I could be missing something fundamental here, and I don't doubt that at all, but if not, wouldn't we need a clock that was not physically affected by gravity in this manner? As I was writing this I see where I may have gone wrong, but I am having trouble nonetheless. Hopefully someone understands what I am trying to say and am asking, knows where I have gone wrong, and can explain it in a way I can understand. That is a very tall order in my opinion, so I will not be upset if no one can provide me with the correct insight on the subject.

I tried searching both ATS and the web but my main problem is that I cannot develop a search term adequate enough to return the proper results. Surely there have been many other people who have been confused by this aspect of time, and have asked basically the same questions I have, but I cannot find anything addressing this particular issue. Any insight will be greatly appreciated, and I know there are a handful of very intelligent persons when it comes to physics on these forums, so hopefully one of them sees this and can understand and explain what I am attempting to get across.

To answer your question, The person flying out experiencing the slowing of the clock ages slower than the person on ground with the faster clock.

That's how they determine the slowing. The twin flying out experiences time normally the one on earth experiences it normally too. However when they come back they see that one is aged a little more (Depending on circumstances) than the other.

This has to do with the gravity both are experiencing. Also relative to the speed one travels.


I totally understand what you're saying. Read about General Relativity and Time Travel.

Time dilation is permitted by Albert Einstein's special and general theories of relativity. These theories state that, relative to a given observer, time passes more slowly for bodies moving quickly relative to that observer, or bodies that are deeper within a gravity well.[57] For example, a clock which is moving relative to the observer will be measured to run slow in that observer's rest frame; as a clock approaches the speed of light it will almost slow to a stop, although it can never quite reach light speed so it will never completely stop. For two clocks moving inertially (not accelerating) relative to one another, this effect is reciprocal, with each clock measuring the other to be ticking slower. However, the symmetry is broken if one clock accelerates, as in the twin paradox where one twin stays on Earth while the other travels into space, turns around (which involves acceleration), and returns—in this case both agree the traveling twin has aged less.

I sat around one day at work and thought it through and researched it. Basically used the other side of my brain to understand it.

There's a lot more to it though...

Originally posted by winofiend
reply to post by JiggyPotamus

 

Relativity.

Everything is relative.

It's easy to get lost in the complexity of it, I often get lost in it, and it's an uncomfortable bewilderment.

It doesn't answer anything, but it provides an insight into how reality works.

Time to an external observer is different to the time of a thing being observed.

Yeah exactly. It's something that you do end up getting lost in. But once you figure it out and how it all works it's like the eureka! moment.

reply to post by Phage

Which is what I said in the next line. The milky way moves at 600m/s. Are you able to tell that your clock is slower than someone outside the galaxy not moving? Frames of references move at different speeds in space-time. The beauty of the special theory of relativity is that we can approximate time dilation in different frames of references without the need of an absolute system, there is no absolute system.

reply to post by an0nThinker

Just the speed of light.

Originally posted by an0nThinker
reply to post by Phage

 

Which is what I said in the next line. The milky way moves at 600m/s. Are you able to tell that your clock is slower than someone outside the galaxy not moving? Frames of references move at different speeds in space-time. The beauty of the special theory of relativity is that we can approximate time dilation in different frames of references without the need of an absolute system, there is no absolute system.

I feel like there is an absolute system. Which would be a black hole or something. But I think you would need to be able to figure out antimatter before you used that in an equation. I don't think every black hole would have the same dilation.

Unless the speed of light was the same getting sucked through a black hole.

They say you get as small as a strand of spaghetti. So wouldn't every black hole have the same singuarity?

reply to post by JiggyPotamus

So my question is how can it be determined that time is actually what is slowing down, considering that it cannot be freed from the physical constraints of the measuring device

The physical parameters of the measuring device can be measured by other devices in other frames of reference. This allows us to calibrate the device and establish values for its performance.

Originally posted by Phage
reply to post by an0nThinker

 

Just the speed of light.

Except for the experiments I recall recently that showed the speed of light is not constant in every instance (my apologies for the lack of reference but I hope you recall this too). Which if it is not always constant, it throws a monkey wrench in the idea that you so eloquently expressed above. Star for that well stated explanation Phage. For the sake of being bound on this planet, I would have to agree with the concept you expressed which is the closest I think anyone here could do for an attempt at explaning what is witnessed.

I can't help but wonder what time differences might be like though to be in a tin can circling Jupiter compared to someones time on the surface, if you could get an observation from the surface. I mean would this be more like a 5 minute difference or something much greater? My gut feeling is only 5 minutes but because of the intense gravity there could be another mechanism that begins to noticably affect the results.

The clock example is the hardest to get over because there are so many questions about the clock in gravity. Is it a digital clock or a cuckoo clock with cords reliant on gravity to do ticking? Maybe it was ticking slower because the batteries are dying. Clocks don't actually do time, they just regularly change shape into a bunch of pre-programmed numbers. And we may never get there because they don't have electrical outlets light years away from Earth. It is a mystery why they use the twin clocks as a time relevancy tool. Only good on Earth to Earth, and that's only if one of them isn't playing games with Daylight Savings Time numbers, and hopefully they are both on the same side of the international date line.

And the most absurd question in my mind is: what time is it on those 2 hypothetical clocks? AM or PM, that is mystery. Like, what if one clock says noon, and another clock 12 light-hours away says 12 o'clock, but it's actually midnight there, would we be able to tell the difference? Wouldn't you have to put a broken clock through a time distortion to make sure that is the one sent out for comparison? Or I have this crazy idea, what if we sent a non-working clock into outer space, and got it back, and it was ticking? Okay that's stupid.

What a waste of time.

A simple way to see time is a memory of degradation from a one-point moment to a non-one-point moment, in linear fashion. Like a graph with an x-y-z. I can barely handle clocks so my math may be worse. You're looking for a relevancy measuring device.

How about a gravimetric interferometer? It measures distortions of gravity from stars, makes stellar distance easier to comprehend for astrophysicists. Then think about caesium clocks.