Gravitational time dilation, proper time and spacetime interval

Click For Summary

Discussion Overview

The discussion revolves around gravitational time dilation as described in the context of Schwarzschild geometry. Participants explore the relationship between proper time and the spacetime interval, particularly focusing on the implications of non-inertial observers and the conditions under which the spacetime interval equals proper time. The scope includes theoretical considerations and mathematical reasoning.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about the derivation of gravitational time dilation, questioning the validity of equating the spacetime interval with proper time for a non-inertial observer.
  • Another participant argues that the differential form of the spacetime interval and proper time are equivalent when integrated, but acknowledges the initial confusion regarding their application to non-inertial observers.
  • Some participants clarify that the relationship between proper time and the spacetime interval holds by definition, regardless of whether the observer is inertial or not.
  • A participant raises the issue of finite versus infinitesimal differences, suggesting that while the infinitesimal relationship holds, the finite relationship may not be straightforward for non-inertial observers.
  • There is a discussion about the implications of metric components not depending on time, which some participants suggest might explain the observed equality of proper time and spacetime interval for non-inertial observers.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the implications of the relationship between proper time and the spacetime interval for non-inertial observers. There are competing views regarding the interpretation of these relationships and the conditions under which they hold.

Contextual Notes

Participants note that the discussion involves complexities related to the definitions of proper time and spacetime intervals, particularly in the context of non-inertial frames. The distinction between infinitesimal and finite differences is highlighted as a source of confusion.

  • #61
A recent thread derail has been deleted, and the thread is reopened
 
  • Like
Likes   Reactions: haushofer
Physics news on Phys.org
  • #62
Hi.
haushofer said:
I agree that the coordinate time is a bookkeeping device, but you can stick an observer to it. I'd say the coordinate t is measured as the time difference between the two events by an observer very far away from the black hole where spacetime can be considered to be flat.
P.247 of the text https://archive.org/stream/TheClassicalTheoryOfFields/LandauLifshitz-TheClassicalTheoryOfFields#page/n257/mode/2up/search/world+time
calls this coordinate time under stationary gravitation the world time. I am not sure whether the naming is popular but common and universal nature of the coordinate time in the sense that everybody in everywhere can translate it to his or anybody's real time is well expressed in this naming. Best.
 
  • Like
Likes   Reactions: haushofer
  • #63
sweet springs said:
Hi.

P.247 of the text https://archive.org/stream/TheClassicalTheoryOfFields/LandauLifshitz-TheClassicalTheoryOfFields#page/n257/mode/2up/search/world+time
calls this coordinate time under stationary gravitation the world time. I am not sure whether the naming is popular but common and universal nature of the coordinate time in the sense that everybody in everywhere can translate it to his or anybody's real time is well expressed in this naming. Best.
So what? This should be true for any coordinate system and there is nothing special about Schwarzschild coordinates apart from what I mentioned in #58. If you pick a different foliation of space-time, any observer will still be able to identify what the corresponding time coordinate is.
 

Similar threads

  • · Replies 37 ·
2
Replies
37
Views
4K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 103 ·
4
Replies
103
Views
7K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 79 ·
3
Replies
79
Views
5K
  • · Replies 35 ·
2
Replies
35
Views
6K
  • · Replies 31 ·
2
Replies
31
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K