Fewer seconds or shorter seconds?

[Kairos]

they do not agree, at least not in the naive sense that you are assuming.

I used "during the flight" to shorten "somewhere between the spacetime point of separation and the spacetime point of reunion of the brothers". I am sure the brothers would have agreed on this term and that you also perfectly understood. The time elapsed on the brother's clocks between these points is the subject of the twin experiment.

 

[jbriggs444]

I used "during the flight" to shorten "somewhere between the spacetime point of separation and the spacetime point of reunion of the brothers". I am sure the brothers would have agreed on this term and that you also perfectly understood. The time elapsed on the brother's clocks between these points is the subject of the twin experiment.

If you tighten that up to be "in the intersection of the future light-cone of the separation event and the past light-cone of the reunion event" then I have no objection.

"Between" is rather more ambiguous than that.

 

[Kairos]

of course! thank you for this precision; unfortunately not always repected in the literature such as for example in reports on atomic clocks in airplanes in which I read "during the trip". It takes very long sentences to speak about relativity in this forum but fortunately equations are simpler (... provided their variables are clearly defined )

 

[vanhees71]

Yes, write equations! Math is the only language adequate to express what one really means!

 

[robphy]

Yes, write equations! Math is the only language adequate to express what one really means!

and write words and draw diagrams (also aspects of Math) !

"A spacetime diagram is worth a thousand words."