Time Dilation in Gravitational Fields vs Acceleration on Earth

In summary, the conversation discusses the effects of time dilation in different scenarios, specifically in gravitational fields and when accelerating. It is clarified that there is no time dilation due to acceleration, but rather due to gravitational potential. The conversation also delves into the concept of a pseudo gravitational field in an accelerating reference frame.
  • #1
mcgnms
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TL;DR Summary
Is the time dilation of being in a gravitational field additive to acceleration since geodesics also experience time dilation?
If I'm standing on Earth, is my time dilation actually greater than if I was in a rocket accelerating at 9.8m/s^2 in deep space due to me being in a gravitational field on top of the acceleration? Geodesics experience time dilation in gravitational fields, so it seems like there is an additive effect, right? I'm trying to eliminate special relativity and kinetic time dilation out of this equation, purely looking at three components here:

1) Time dilation just by being in a gravitational field
2) Time dilation from acceleration
3) Time dilation from resisting free fall in a gravitational field

Is #3 some combination of #1 and #2?
 
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  • #2
There is no time dilation due to acceleration, neither gravitational nor any other type.

Gravitational time dilation is due to gravitational potential, and that is the same whether it is gravitational potential from a real gravitational field or the pseudo “gravitational” potential from an accelerating reference frame.
 
  • #3
Dale said:
There is no time dilation due to acceleration, neither gravitational nor any other type.

Gravitational time dilation is due to gravitational potential, and that is the same whether it is gravitational potential from a real gravitational field or the pseudo “gravitational” potential from an accelerating reference frame.
Right, but my question still stands. Are these effects additive? When you stand on Earth's surface, whether or not you're in free fall or standing on the surface...you have gravitational potential. Now on top of that, since you're standing (and therefore accelerating at 1G), you have even more gravitational potential, right?

Another analogy to get to the root of my question. Say Observer A is standing on the surface of Earth and Observer B, right next to them, begins free fall down a deep hole into the earth. At the very moment Observer B begins free fall, they are still just as deep in Earth's gravity well, but are also not accelerating anymore. Therefore, is their clock less dilated at that instant now?
 
  • #4
mcgnms said:
Now on top of that, since you're standing (and therefore accelerating at 1G), you have even more gravitational potential, right?
No. Why would this be true? Gravitational potential is purely about your position in the gravitational field, not your acceleration.
 
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  • #5
I'm confused then, you just said that acceleration creates a pseudo gravitational field that acts like gravitational potential. Did I understand that correctly? So by resisting free fall and therefore accelerating, you presumably create gravitational potential, right?
 
  • #6
mcgnms said:
I'm confused then, you just said that acceleration creates a pseudo gravitational field that acts like gravitational potential. Did I understand that correctly?
No. I said that an accelerating reference frame has a pseudo gravitational field and potential. If you use an accelerating reference frame then there will be “gravitational” time dilation both for accelerating and non-accelerating clocks. If you use an inertial frame there will be no gravitational time dilation for accelerating nor non-accelerating clocks.
 
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  • #7
Dale said:
If you use an accelerating reference frame then there will be “gravitational” time dilation both for accelerating and non-accelerating clocks. If you use an inertial frame there will be no gravitational time dilation for accelerating nor non-accelerating clocks.
Are you talking about proper acceleration for the clocks or just their coordinate acceleration w.r.t. the chosen reference frame ?
 
  • #8
cianfa72 said:
Are you talking about proper acceleration for the clocks or just their coordinate acceleration w.r.t. the chosen reference frame ?
I was talking about coordinate acceleration.
 
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1. What is time dilation in gravitational fields?

Time dilation in gravitational fields is a phenomenon where time passes at a slower rate for objects in strong gravitational fields. This is due to the curvature of spacetime caused by the presence of massive objects, such as planets or stars.

2. How does time dilation in gravitational fields differ from acceleration on Earth?

Time dilation in gravitational fields is caused by the curvature of spacetime, while acceleration on Earth is caused by the force of gravity. While both result in a slowing of time, the mechanisms behind them are different.

3. Is time dilation in gravitational fields a proven concept?

Yes, time dilation in gravitational fields has been proven through various experiments and observations, including the famous Hafele-Keating experiment in 1971 and the observation of gravitational time dilation in the orbit of Mercury.

4. How does time dilation in gravitational fields impact our daily lives?

In our daily lives, the effects of time dilation in gravitational fields are negligible. However, it is taken into account in technologies such as GPS, which rely on precise time measurements for accurate location tracking.

5. Can time dilation in gravitational fields be reversed?

No, time dilation in gravitational fields cannot be reversed. It is a fundamental aspect of the laws of physics and cannot be altered or reversed by any known means.

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