Brent, No it's not "an observation that the two twins are together at particular spacetime coordinates" because the spacetime t coordinates are different.
Since the spacetime t coordinates are different WHEN are they together? Certainly not in a simultaneous clock time as proved by their differing clocks. When are they together Brent? Obviously in a present moment which is a kind of time that clearly is not the same as clock time. Edgar On Monday, January 6, 2014 12:18:16 AM UTC-5, Brent wrote: > > On 1/5/2014 12:00 PM, Edgar L. Owen wrote: > > Brent, > > > > No, the present moment is NOT just a "label". It's an empirically > verifiable observation > > (measurement). And not only that both twins agree on that measurement, > namely that they > > have different clock times in the same shared present moment. > > > > There is simply no way around that.... > > > > Edgar > > Of course it's an observation. It's an observation that the two twins are > together at > particular spacetime coordinates. I have no problem with you calling that > a present > moment (although everyone else calls it an event). The problem is not > that you can't > define a global time at which they meet, it's that you can't define a > *unique* global > time. There are infinitely many choices of coordinate time and they will > all agree that > the twins meet at the same coordinate time - but they will not agree as to > which other > distant events in the universe are at the same time as the meeting. > > Brent > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to firstname.lastname@example.org. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.