Why does time tick at different rates at different locations?

[Vay]

I can understand why time will tick differently for two objects moving at different speeds, but why does time tick at different rates at different locations (or did I misinterpret something)?

 

Edit:

 

In other words, how do two people moving at the same speed have watches that tick un-synchronized just because they are at two different locations.

Edited March 19, 2011 by Vay

[farmboy]

I'm not a physicist mate, so I am probably wrong, but as far as I know that is not true. Well I dunno maybe gravity somehow affects the rate at which time pases relative to an observer, but even if that is the case it doesn't mean that time moves differently because you are simply in another place, that is just a coincidence.

[lemur]

Swanson explained it really well in another post, but let me see if I can put it in very tangible terms. Supposedly, if you were on a very tall mountain looking down at a very deep valley with gravity much higher than on the mountain, you would look through your telescope and see the people in the valley moving in fast motion. This is how I currently understand it anyway.

[Vay]

Swanson explained it really well in another post, but let me see if I can put it in very tangible terms. Supposedly, if you were on a very tall mountain looking down at a very deep valley with gravity much higher than on the mountain, you would look through your telescope and see the people in the valley moving in fast motion. This is how I currently understand it anyway.

 

But those two people are stationary, so how does time pass differently? Although the Earth accelerates the two subjects, the ground pushes back with the same force so they don't move anywhere. What probably happens is because they are at different positions on the Earth, when the Earth rotates, one subject is being accelerated more by the Earth's rotation so he experiences a difference in time, although it might be extremely minuscule. But this explanation does not work if two people are at different locations suspended in space in a free fall moving at the same constant speed.

Edited March 19, 2011 by Vay

[lemur]

But those two people are stationary, so how does time pass differently? Although the Earth accelerates the two subjects, the ground pushes back with the same force so they don't move anywhere. What probably happens is because they are at different positions on the Earth, when the Earth rotates, one subject is being accelerated more by the Earth's rotation so he experiences a difference in time, although it might be extremely minuscule. But this explanation does not work if two people are at different locations suspended in space in a free fall moving at the same constant speed.

My understanding is that while the effect could be due to speed differences that are close to the speed of light, it can also be due to gravity, which is what I was describing. I don't know why the observer on the mountain sees the people in the valley moving in fast motion even though they experience themselves as moving at regular speed. Imo, it seems like it should have something to do with the effect of force on energy-motion relative to electron frequencies, but that is pure speculation as far as I know. The effect is even stranger when the observer's time is dilated relative to the observed-situation because observers in both positions observe the other's time as accelerated, I believe. I could be getting this wrong, though. I always get confused when I start trying to think about all the implications and whether they make sense.

[farmboy]

Do you have anything to actually back up the claim that time passes at different rates at different points in the universe for reasons that can't be explained by gravity or velocity. When I thought about my first post again, it is definitely true that gravity affects that rate at which time passes, though I think the difference is negligible barring super gravitational effects. And then obviously the speed at which you are travelling will be a factor, so the person who is at the top of the mountain will be moving faster but will experience less gravitational effects. But of course these effects are entirely negligible, but then there will be some slightly different gravitational effect everywhere in the universe and maybe this is what was meant by your originl statement?

[J.C.MacSwell]

Think of a light clock just outside the event horizon of a black hole positioned so that the light bounces radially. Obviously the "up tick" will ensure that this clock runs very slowly compared to a similar one at a safe distance. where gravity is stronger (or acceleration is greater) time runs slower.

[swansont]

I can understand why time will tick differently for two objects moving at different speeds, but why does time tick at different rates at different locations (or did I misinterpret something)?

 

Edit:

 

In other words, how do two people moving at the same speed have watches that tick un-synchronized just because they are at two different locations.

 

Gravity warps space, and because c is a constant, space and time are related.

[lemur]

Gravity warps space, and because c is a constant, space and time are related.

But relative to the high-gravity situation she is ascending from, the low-gravity observer's time is literally decelerating relative to those she observes below her. So what is it about lower-gravity that allows her time to elapse slower? It doesn't have to do with the speed of energy at the atomic level or something like that?

[Vay]

Gravity warps space, and because c is a constant, space and time are related.

 

If two people are experiencing the same gravitational pull in all respects, does location still un-synchronize their watches? I read in a book that put it a bit vaguely about how no where in the universe does time tick simultaneously.

[J.C.MacSwell]

But relative to the high-gravity situation she is ascending from, the low-gravity observer's time is literally decelerating relative to those she observes below her. So what is it about lower-gravity that allows her time to elapse slower? It doesn't have to do with the speed of energy at the atomic level or something like that?

 

Higher gravity, or equivalently greater acceleration. With lower gravity or less acceleration time elapses faster.

[swansont]

It's not the gravitational pull (g) that matters, it's the gravitational potential. i.e. where you are in the gravity well, not how steep the walls are. Two people with the same gravitational potential and at rest with respect to each other see no change in the rate of their clock (i.e. the frequency of the oscillator). The potential is related to how much curvature there is, and therefore how much time is dilated.

[lemur]

Two people with the same gravitational potential and at rest with respect to each other see no change in the rate of their clock (i.e. the frequency of the oscillator). The potential is related to how much curvature there is, and therefore how much time is dilated.

How is the atomic decay that drives an atomic clock based on oscillation?

[keelanz]

simplest way i could define it would be that if time is what happens when change occurs(and calculable to it), then its relative to that change

gravity is the fundamental force of change (other than the big bang)

our planet and conditions are set at an almost constant rate which makes our time systems and lifespan nothing but appropriate to us

therefore towards the outer reaches of the universe (any drastic change in forces) time would run slower but perceived as the same (you could live 3 times as long with 3 times less force but you wouldnt know it, its just relative)

 

in other words when a mass is torn between two forces (or that force is weak) what we define as time would be almost non existent & when we have lots of forces all acting upon each other we have array of change and hence the speeding up of time

 

It's not the gravitational pull (g) that matters, it's the gravitational potential. i.e. where you are in the gravity well, not how steep the walls are. Two people with the same gravitational potential and at rest with respect to each other see no change in the rate of their clock (i.e. the frequency of the oscillator). The potential is related to how much curvature there is, and therefore how much time is dilated.

 

are you saying that time is relative to the potential force of gravity? like being calculable to it?

 

But those two people are stationary, so how does time pass differently? Although the Earth accelerates the two subjects, the ground pushes back with the same force so they don't move anywhere. What probably happens is because they are at different positions on the Earth, when the Earth rotates, one subject is being accelerated more by the Earth's rotation so he experiences a difference in time, although it might be extremely minuscule. But this explanation does not work if two people are at different locations suspended in space in a free fall moving at the same constant speed.

 

well you contradicted yourself straight away

"But those two people are stationary","What probably happens is because they are at different positions on the Earth, when the Earth rotates" also "suspended in space in a free fall"

Edited March 19, 2011 by keelanz

[swansont]

How is the atomic decay that drives an atomic clock based on oscillation?

 

Atomic clocks do not depend on decay. The oscillation is a transition between atomic states. In most of the clocks in use this is a spin-flip, but cutting edge clocks/frequency standards are using higher-energy transitions.

[lemur]

Atomic clocks do not depend on decay. The oscillation is a transition between atomic states. In most of the clocks in use this is a spin-flip, but cutting edge clocks/frequency standards are using higher-energy transitions.

What is a "higher-energy transition" than spin-flip? And why is spin-flip better for time-keeping using radioactive atoms? And why would spin-flip occur more often in the same material at lower gravity or slower speeds? Do electron clouds literally dilate and contract due to gravity or speed?

[keelanz]

.............really

 

http://www.youtube.com/watch?v=oiz-BwT5wZU&feature=player_embedded#at=225

Edited March 20, 2011 by keelanz

[swansont]

What is a "higher-energy transition" than spin-flip? And why is spin-flip better for time-keeping using radioactive atoms? And why would spin-flip occur more often in the same material at lower gravity or slower speeds? Do electron clouds literally dilate and contract due to gravity or speed?

 

Higher energy is a higher frequency. The commonly available atomic clocks use what is called a hyperfine transition (the spin flip) which is in the microwave region of the spectrum (6.8 GHz for Rb, 9.2 GHz for Cs). Visible light has a higher energy, so transitions using lasers are being investigated and developed.

 

The transitions happen more slowly because time runs at a different rate when you are moving or at a different gravitational potential. IOW, Relativity.

[lemur]

Higher energy is a higher frequency. The commonly available atomic clocks use what is called a hyperfine transition (the spin flip) which is in the microwave region of the spectrum (6.8 GHz for Rb, 9.2 GHz for Cs). Visible light has a higher energy, so transitions using lasers are being investigated and developed.

So how does that work then? Atoms are heated to microwave frequencies and then their spin flip somehow monitored?

 

The transitions happen more slowly because time runs at a different rate when you are moving or at a different gravitational potential. IOW, Relativity.

I already got that, thanks. What I'm trying to understand is how gravity affects the rate of events, since it must occur at the sub-atomic level for even the spin flipping of electrons to be affected, right?

 

 

[swansont]

So how does that work then? Atoms are heated to microwave frequencies and then their spin flip somehow monitored?

 

Heating isn't the right paradigm; it's a single transition. The atoms are put in a state where the electrons oscillate between two states. You basically count the oscillations.

 

 

I already got that, thanks. What I'm trying to understand is how gravity affects the rate of events, since it must occur at the sub-atomic level for even the spin flipping of electrons to be affected, right?

 

Time slows down (or speeds up). So the rate at which any oscillations occur, or any other sequence of events happens, has to change.

[lemur]

Heating isn't the right paradigm; it's a single transition. The atoms are put in a state where the electrons oscillate between two states. You basically count the oscillations.

What kind of "state" then?

 

Time slows down (or speeds up). So the rate at which any oscillations occur, or any other sequence of events happens, has to change.

I don't see time as a cause of events but as a pattern of rate-consistency. So if something (gravity/speed) is causing different rates of separate processes to vary together, I would like to know how these rates are being influenced by the causal factor(s).

 

 

[swansont]

What kind of "state" then?

A superposition of the two hyperfine levels of the ground state of the atom. There are two because the electron has two spin orientations possible, and they have a small difference in their energy. The atoms behave like the electrons are oscillating between the two levels.

 

I don't see time as a cause of events but as a pattern of rate-consistency. So if something (gravity/speed) is causing different rates of separate processes to vary together, I would like to know how these rates are being influenced by the causal factor(s).

 

It's not a matter of "cause," since it's not a mechanical effect like friction. Time is how you measure the rate; time slows down, so the you will get a different rate. This has been experimentally verified.

[lemur]

A superposition of the two hyperfine levels of the ground state of the atom. There are two because the electron has two spin orientations possible, and they have a small difference in their energy. The atoms behave like the electrons are oscillating between the two levels.

So, what is it, "up spin" and "down spin?" Which one has slightly higher energy? Is the difference related to asymmetry in the electron caused by force, i.e. gravity or other acceleration? Are the electron clouds of atoms slightly pear-shaped in other words, instead of perfectly spherical?

 

It's not a matter of "cause," since it's not a mechanical effect like friction. Time is how you measure the rate; time slows down, so the you will get a different rate. This has been experimentally verified.

But for motion in the observed frame to occur at a faster rate relative to the observer frame, doesn't something have to be occurring faster or slower in the respective frames? If not, wouldn't oscillations occur at the same rate relative to the expanded or contracted spacetime matrix/geometry?

 

 

[swansont]

So, what is it, "up spin" and "down spin?" Which one has slightly higher energy? Is the difference related to asymmetry in the electron caused by force, i.e. gravity or other acceleration? Are the electron clouds of atoms slightly pear-shaped in other words, instead of perfectly spherical?

 

We've had a rather extensive thread discussing spin, in which you were involved. I really have no inclination to answer these questions yet again.

 

But for motion in the observed frame to occur at a faster rate relative to the observer frame, doesn't something have to be occurring faster or slower in the respective frames? If not, wouldn't oscillations occur at the same rate relative to the expanded or contracted spacetime matrix/geometry?

 

Time is going faster or slower. A rate is a number per unit time. So no, the rate would not stay the same.

[niebieskieucho]

I can understand why time will tick differently for two objects moving at different speeds, but why does time tick at different rates at different locations (or did I misinterpret something)?

Yeah, you definitely did, because time doesn't tick.

In other words, how do two people moving at the same speed have watches that tick un-synchronized just because they are at two different locations.

Maybe my undermentioned article will give you answer to this question (impact of changed conditions).

url deleted

 

--

Ihad a dream that on my yard a UFO landed but when I woke up, they hadalready gone

Edited April 12, 2011 by swansont
delete hijack URL