Is Gravity the only force that affects time?

In summary: Weak fields will cause time dilation only insofar as they distort spacetime, but they can't cause the time dilation itself. Strong fields will cause time dilation and space-time curvature, which would cause a slower passage of time for an object within them.
  • #1
ChromeBit
27
0
Sorry I'm new to this.
There are apparently four forces in the universe: Gravity, EM, Weak and Strong.
Is gravity the only force that can cause time dilation, or can the other forces affect time too?
 
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  • #2
ChromeBit said:
Sorry I'm new to this.
There are apparently four forces in the universe: Gravity, EM, Weak and Strong.
Is gravity the only force that can cause time dilation, or can the other forces affect time too?

In special relativity (or, hypothetically far from all gravitational mass), clocks that are moving with respect to an inertial system of observation are measured to be running more slowly. This effect is described precisely by the Lorentz transformation.
So no gravity is involved.
 
  • #3
ChromeBit said:
Sorry I'm new to this.
There are apparently four forces in the universe: Gravity, EM, Weak and Strong.
Is gravity the only force that can cause time dilation, or can the other forces affect time too?

As far as I know, only gravity "affects" time. As measured by a distant observer, time passes more slowly for an object deep in strong gravitational well than it does for the distant observer. Note, however, that the time is NOT locally affected. That is, both the time dilation due to motion described by adjacent (which, as he said has nothing to do with gravity) and gravitational time dilation I just mentioned, are only artifacts of remote observation. A person with a clock in his hand sees that clock tick at one second per second regardless of whether he is in motion (which we all are, after all, since motion is relative) or in a gravity well.
 
  • #4
phinds said:
Note, however, that the time is NOT locally affected.

Quite the contrary-kinematical time dilation occurs locally in general relativity. Only gravitational time dilation is non-local.

OP, the reason only gravity affects the "flow of time" is GR models gravitation as space-time geometry itself and space-time geometry fully determines the behavior of standard clocks and rods. Within the framework of GR all other classical fields, such as the electromagnetic field, simply propagate on the dynamical curved background. Note however that the electromagnetic field generates a gravitational field because it carries energy and momentum. As a result it can induce space-time curvature and potentially lead to gravitational time dilation effects indirectly in this sense.
 
  • #5
WannabeNewton said:
Quite the contrary-kinematical time dilation occurs locally in general relativity. Only gravitational time dilation is non-local.

Locally, but only to 'someone else', obviously. It is never experienced by 'you'.
 
  • #6
WannabeNewton said:
Quite the contrary-kinematical time dilation occurs locally in general relativity.
I have explained several times to phinds that calling kinematic time dilation an "artifact of remote observation" is highly misleading, if not plain wrong:
https://www.physicsforums.com/showthread.php?p=4625906
 
  • #7
A.T. said:
I have explained several times to phinds that calling kinematic time dilation an "artifact of remote observation" is highly misleading, if not plain wrong:
https://www.physicsforums.com/showthread.php?p=4625906

Yes, you have and I guess I'm still confused. Aside from out disagreement about my use of the term "artifact", the more fundamental issue is that, if I understand it correctly, and it seems you are saying I don't and Pallen is saying I do, is that YOU always observe your local time as being "normal".

This, I guess, gets a bit tricky to define. If I say "your proper time is passing at one second per second" then we have the problem of how do we measure that proper time? What ever is being used to measure it is in the same frame of reference so is subject to the same effects.
 
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  • #8
ChromeBit said:
Sorry I'm new to this.
There are apparently four forces in the universe: Gravity, EM, Weak and Strong.
Is gravity the only force that can cause time dilation, or can the other forces affect time too?

Yes, it is. Electric fields, no matter how strong, won't cause time dilation (except insofar as they may contribute to gravity - but it's the gravity that causes the time dilation, even in that case).
 

1. What is the relationship between gravity and time?

Gravity and time are closely related, as gravity is one of the fundamental forces that affects the fabric of space-time. According to Einstein's theory of general relativity, the presence of mass or energy causes a curvature in space-time, which we experience as the force of gravity. This curvature also affects the passage of time, causing it to slow down near massive objects.

2. Is gravity the only force that affects time?

No, gravity is not the only force that affects time. Other forces, such as velocity and electromagnetic fields, can also influence the passage of time. However, gravity is often considered the most significant force in terms of its effect on time.

3. How does gravity affect time differently in different situations?

The effect of gravity on time depends on the strength of the gravitational field and the speed of the observer. In a strong gravitational field, time moves slower, while in a weaker gravitational field, time moves faster. Additionally, the faster an object moves, the slower time moves for that object.

4. Can gravity affect time in outer space where there is no mass?

Yes, gravity can still affect time in outer space even where there is no mass. This is because space itself has a curvature due to the presence of energy and matter, even in the absence of massive objects. This curvature can cause time to slow down or speed up.

5. How does the concept of time dilation relate to gravity?

Time dilation, which is the difference in the passage of time between two observers in different reference frames, is directly related to gravity. The stronger the gravitational field, the greater the time dilation. This can be observed in phenomena such as gravitational time dilation near black holes or in the global positioning system (GPS), where precise adjustments must be made to account for the difference in time due to Earth's gravitational field.

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