Can anyone to study a simple case of GR.?

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Discussion Overview

The discussion revolves around gravitational time dilation in the context of General Relativity (GR), specifically comparing the experiences of two observers: one on Earth and another far from Earth. Participants seek to understand the implications of time flow as experienced by these observers and the relevant formulas in GR.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes a scenario involving two observers, A on Earth and B far from Earth, questioning the time flow experienced by A relative to B.
  • Another participant reiterates the same scenario and seeks explicit explanations and formulas related to gravitational time dilation in GR.
  • Several participants discuss the implications of light observed from a distant location and how it relates to time dilation, suggesting that both the light and the time-dilated observer appear to have slower proper time compared to local observations.
  • A participant critiques the clarity of the formulation regarding the relationship between gravitational time dilation and the constancy of the speed of light, noting that the speed of light is a local constant in GR.
  • There is a reference to a specific chapter in a text that discusses the measurement of light speed at different gravitational potentials, highlighting the differences in clock rates and ruler lengths between observers at different heights.
  • One participant questions whether others understand the equations provided in the Wikipedia link regarding gravitational time dilation.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and clarity regarding the concepts of gravitational time dilation and the implications for the speed of light. There is no consensus on the clarity of the explanations provided, and multiple interpretations of the scenarios and equations are present.

Contextual Notes

Participants reference specific texts and external links for further clarification, indicating that there may be assumptions or definitions that are not universally agreed upon. The discussion includes complex ideas that may not be fully resolved within the thread.

aditya23456
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consider a following situation,where a person A is on Earth and another one B far from Earth where his proper time is not influenced by Earth's gravity field.now what's time flow felt by A wrt A and wrt to B.?
I get the answer for it but i need a explicit explanation..Is there any link where I can get formulae for this using GR.??thanks in advance
 
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aditya23456 said:
consider a following situation,where a person A is on Earth and another one B far from Earth where his proper time is not influenced by Earth's gravity field.now what's time flow felt by A wrt A and wrt to B.?
I get the answer for it but i need a explicit explanation..Is there any link where I can get formulae for this using GR.??thanks in advance
http://en.wikipedia.org/wiki/Gravitational_time_dilation
 
what does this mean----
"If a distant observer is able to track the light in
a remote, distant locale which intercepts a time
dilated observer nearer to a more massive
body, he sees that both the distant light and
that distant time dilated observer have a
slower proper time clock than other light which is coming nearby him, which intercepts
him, at c, like all other light he really can
observe. When the other, distant light
intercepts the distant observer, it will come at c
from the distant observer's perspective."
 
aditya23456 said:
what does this mean----
"If a distant observer is able to track the light in
a remote, distant locale which intercepts a time
dilated observer nearer to a more massive
body, he sees that both the distant light and
that distant time dilated observer have a
slower proper time clock than other light which is coming nearby him, which intercepts
him, at c, like all other light he really can
observe. When the other, distant light
intercepts the distant observer, it will come at c
from the distant observer's perspective."
That's very messy formulation. Gravitational time dilation and length contraction imply that in GR the speed of light is only a local constant.

-> that is also mentioned in par.5 of chapter 22 here:
http://www.bartleby.com/173/22.html

For example, take the measurement of the speed of light of a horizontally propagating light ray at great height, using a standard ruler, a clock and a mirror. For simplicity assume this is done in vacuum and ignore the rotation of the Earth (or have it measured in an airplane that flies against the rotation of the Earth, thus cancelling it).
Then the speed as measured with those local instruments will be c. However, according to a reference system with otherwise identical instruments at sea level, the ruler in the airplane has the same length but the airplane clock is running fast.

BTW, do you understand the equations given in the wiki?
 
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