Using time dilation to measure curvature of space-time

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Using time dilation to measure curvature of space-time

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Post by notFritzArgelander »


https://phys.org/news/2022-01-dilation- ... -time.html

This is very interesting and I am curious about the reference to the Aharonov-Bohm effect.

https://en.wikipedia.org/wiki/Aharonov–Bohm_effect

In classical physics the potential ones not affect charges directly. In quantum physics potentials directly influence charged particles through the phase of the wave function.

https://www.science.org/doi/10.1126/science.abm6854
In Einstein’s theory of general relativity, gravity is a manifestation of spacetime curvature. As predicted by general relativity and confirmed by numerous measurements, clocks moving at different velocities or located in different regions of a gravitational field tick at different rates (1), a phenomenon known as relativistic time dilation. Under appropriate conditions, time dilation can affect the oscillation phase of quantum waves and give rise to a measurable effect in interference experiments. On page 226 of this issue, Overstreet et al. (2) present an atom interferometry experiment in which this effect has been measured for gravitational time dilation. In addition to the importance of the results for fundamental physics, the methods used can lead to more accurate measurements of Newton’s gravitational constant, which parametrizes the strength of the gravitational interaction and is by far the least accurately known of all fundamental constants (3).
I'm considering getting the full article.....
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Re: Using time dilation to measure curvature of space-time

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Post by Michael131313 »


Interesting. I have never heard of an atomic fountain before. Thanks nFA.
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Re: Using time dilation to measure curvature of space-time

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Post by chasmanian »


nFA,

General Relativity correctly predicts that clocks run slower in stronger gravitational fields.
do you know, is there a relatively simple way to explain this? what is the mechanism or cause, how does this happen?

I know that massive objects curve spacetime.

but I don't understand in a really simple way, what is going on with the clocks running slower.
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Re: Using time dilation to measure curvature of space-time

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Post by notFritzArgelander »


chasmanian wrote: Sat Jan 15, 2022 2:53 pm nFA,

General Relativity correctly predicts that clocks run slower in stronger gravitational fields.
do you know, is there a relatively simple way to explain this? what is the mechanism or cause, how does this happen?

I know that massive objects curve spacetime.

but I don't understand in a really simple way, what is going on with the clocks running slower.
Well, you've already described in words how this happens: massive objects curve spacetime and so clocks run slow near them. It's the gravitational redshift. ;)

Here's the simplest math for it I know of.

https://en.wikipedia.org/wiki/Gravitati ... celeration

But one can gain some insight by also looking at the Schwarzschild metric.

Spacetime curvature most strongly affects the time component of the metric. Keeping all the other coordinates fixed the proper time interval squared is proportional to (1-Rs/r) times the coordinate time interval (of an observer at infinity) squared. With r (radial location) greater than Rs (the Schwarzschild radius) that means the proper time of the local clock is slower than the coordinate clock.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Using time dilation to measure curvature of space-time

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Post by chasmanian »


thank you nFA.

would you please clarify this for me?

gravitational redshift is dependent on light, or a function (struggling for correct term or wording here) of light.
(please excuse my lack of understanding. I am trying.)

does this mean that clocks running slower in a stronger gravitational field is an observed phenomenon, because of the behavior of light?

does this mean that this phenomenon would not be detectable, if we humans did not have the sense of sight?

if this is not clear,
imagine alien astrophysicists.
they are all blind.
will they not detect the clocks running slower in a stronger gravitational field?
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Re: Using time dilation to measure curvature of space-time

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Post by notFritzArgelander »


chasmanian wrote: Sat Jan 15, 2022 11:54 pm thank you nFA.

would you please clarify this for me?

gravitational redshift is dependent on light, or a function (struggling for correct term or wording here) of light.
(please excuse my lack of understanding. I am trying.)

does this mean that clocks running slower in a stronger gravitational field is an observed phenomenon, because of the behavior of light?

does this mean that this phenomenon would not be detectable, if we humans did not have the sense of sight?

if this is not clear,
imagine alien astrophysicists.
they are all blind.
will they not detect the clocks running slower in a stronger gravitational field?
gravitational redshift is the same as gravitational time dilation is NOT dependent on light. blind alien astrophysicists who were not deaf would hear a tuning fork in a valley at a lower frequency than on a mountaintop. also the astrophysicists in the valley would age more slowly than the ones on the mountaintop.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Using time dilation to measure curvature of space-time

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Post by chasmanian »


thank you nFA.
so very fascinating.

I just had an interesting think about this.

here what I thought

hmmm, how can this be?
isn't sound, mechanical waves.
and I googled for a while.
it was no help.

but then I used my own brain.
and here's what I thought.

the length of a second is different in the valley and the mountaintop (because of gravitational time dilation).
and drum roll, viola (chortle)
thats the reason for the tuning fork frequency being lower in the valley.

hertz are cycles per second.
as the second (the denominator) increases in value, the hertz frequency decreases.

does that sound right to you? (do you see what I did there, and it wasn't even on purpose, I didn't even notice it until l re-read it, before posting.)
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Re: Using time dilation to measure curvature of space-time

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Post by notFritzArgelander »


chasmanian wrote: Sun Jan 16, 2022 4:09 am thank you nFA.
so very fascinating.

I just had an interesting think about this.

here what I thought

hmmm, how can this be?
isn't sound, mechanical waves.
and I googled for a while.
it was no help.

but then I used my own brain.
and here's what I thought.

the length of a second is different in the valley and the mountaintop (because of gravitational time dilation).
and drum roll, viola (chortle)
thats the reason for the tuning fork frequency being lower in the valley.

hertz are cycles per second.
as the second (the denominator) increases in value, the hertz frequency decreases.

does that sound right to you? (do you see what I did there, and it wasn't even on purpose, I didn't even notice it until l re-read it, before posting.)
I think you knew exactly what you were doing from "viola" on..... :lol:
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
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Re: Using time dilation to measure curvature of space-time

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Post by chasmanian »


thank you nFA. hahahahaha :)
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