Time dilation or time relativity?

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Discussion Overview

The discussion revolves around the terms "time dilation" and "time relativity," exploring whether they are synonymous or if they convey different concepts within the context of physics, particularly in relation to special relativity (SR). Participants examine the implications of each term and their applications in various frames of reference.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that "time dilation" refers to the phenomenon from the perspective of a single observer, while "time relativity" encompasses all observers.
  • One participant defines "time relativity" as a generic term applicable to various motion theories, including Aristotelian, Galilean, and Einsteinian frameworks, while associating "time dilation" specifically with the effects described by special relativity.
  • A participant provides a scenario involving a journey to a star, illustrating the calculations of time dilation and suggesting that "time relativity" might yield similar interpretations under special relativity.
  • Another participant discusses the Lorentz transformation, indicating that "time dilation" relates to the coefficient of time in the transformation, while "relativity of simultaneity" pertains to the spatial component, and expresses uncertainty about the term "relativity of time."
  • One participant acknowledges their limitations in understanding the topic but attempts to clarify their thoughts on the relationship between the terms.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether "time dilation" and "time relativity" are synonymous or distinct concepts. Multiple competing views are presented, and the discussion remains unresolved.

Contextual Notes

Participants express uncertainty regarding the definitions and implications of the terms, and there are references to specific mathematical formulations without resolving the underlying assumptions or interpretations.

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Are these terms synonyms or do they actually mean different things?

I see both refer to the same phenomenon but it looks as if "time dilation" assumes the point of view of only one observer whereas "time relativity" or "relativity of time" seems to include all the observers. Still, most literature refers to this as "time dilation".
 
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time relativity = a generic term applying to all motion physics - Aristotlean, Galilean, Einsteinian, etc.

time dilation = the phenomenon of time "slowing down" IAW SR (Einsteinian.)

That's a guess...

stevmg
 
Consider the Earth as the center of a frame of reference. Have a star 10 ltyr away. If traveling at 0.6 c it would take you 10/0.6 = 16 2/3 years to get there in the Earth's time frame.

Gamma for this is 0.8, therefore the length contracted distance in the rocket ship's time frame is 8 ltyr.

The "time dilated" (the rocket's time frame) would be 13 1/3 years rather than the 16 2/3 years in Earth time.

That's time dilation. Notice that 8 lt-yr/13 1/3 yr still = 0.6 c

I suppose time relativity would be the same in the sense that most interpret scu a situation in Einsteinian or SR terms.

I bet you I got that all wrong...
 
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The Lorentz transformation of time has the form t'=(\ldots)t+(\ldots)x. To me, "time dilation" has the connotation of referring to the fact that the coefficient of the first term on the right doesn't have its Galilean value of 1, while "relativity of simultaneity" focuses more on the fact that the second coefficient doesn't have its Galilean value of 0. I haven't heard "relativity of time" as much, so I wouldn't hazard a guess as to its connotations; it might be a convenient blanket term for all such relativistic effects.
 
bcrowell said:
The Lorentz transformation of time has the form t'=(\ldots)t+(\ldots)x. To me, "time dilation" has the connotation of referring to the fact that the coefficient of the first term on the right doesn't have its Galilean value of 1, while "relativity of simultaneity" focuses more on the fact that the second coefficient doesn't have its Galilean value of 0. I haven't heard "relativity of time" as much, so I wouldn't hazard a guess as to its connotations; it might be a convenient blanket term for all such relativistic effects.

@bcrowell. You are way out of my league here (that's my "fault") but the highlighted section in your reply was what I was trying to say but couldn't come up with the words.

stevmg
 

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