B What is the Definition of Improper Time in Special Relativity?

[FranzDiCoccio]

Hi all,

this is just a terminology question. I am aware of the definition of "proper time" (and "proper length") in the context of special relativity.
I recently heard the term "improper time", as opposed to proper time, of course.
Is that accepted terminology?

Sounds weird to me.

 

[phinds]

Sounds weird to me too. Must be someone's idea of coordinate time.

 

[FranzDiCoccio]

Phinds, thanks for your help!

Ok so the correct (or accepted) terminology is "coordinate time".
Cool.

I did some searches for "improper time" and I get a relatively small number of hits, which makes me think that this term is at least not very widespread.
However one of these hits is from a somewhat authoritative source...

 

[phinds]

Phinds, thanks for your help!

Ok so the correct (or accepted) terminology is "coordinate time".
Cool.

I did some searches for "improper time" and I get a relatively small number of hits, which makes me think that this term is at least not very widespread.
However one of these hits is from a somewhat authoritative source...

"Time measured with two clocks or a single moving clock." Makes no sense. Time measured with a single moving clock is proper time and time measured with two clocks could mean most anything.

 

[Dale]

I have never heard of the term either. I would stick with “proper time” or “coordinate time”, both of which are well known and useful concepts. Using obscure terms can lead to confusion, even if it has a clear definition, which this one doesn’t.

 

[PeterDonis]

one of these hits is from a somewhat authoritative source...

I think this is Wolfram's idiosyncratic terminology. I've never seen this usage anywhere else.

 

[Jonathan Scott]

In this context of "proper time", the word "proper" is not used in the usual English sense, but is used to mean "one's own" as in the Latin "proprius" from which "proper" is derived, and one of the meanings of "propre" in French. (The word "property" derives from the same source). I think the adjective "proper" in "proper time" was originally a translation of the prefix "eigen" from German, which has a similar meaning and has been left as "eigen" in other terms such as "eigenvalue" and "eigenvector".

 

[jtbell]

Indeed, Eigenzeit is the German for proper time:

https://www.spektrum.de/lexikon/physik/eigenzeit/3707

 

[strangerep]

Here's one example of an improper time.