Jason, What clock measures your coordinate time? Apparently none. It's beginning to sound just like another name for Present time.
What's the difference? Edgar On Monday, January 6, 2014 9:47:36 AM UTC-5, Jason wrote: > > > > On Jan 6, 2014, at 6:55 AM, "Edgar L. Owen" <[email protected] <javascript:>> > wrote: > > Brent, > > No it's not "an observation that the two twins are together at particular > spacetime coordinates" because the spacetime t coordinates are different. > > > Their proper times are different, but not their coordinate times. > > A clock time is only a representation of how much speed (and accordingly > distance) had to be given up to travel through space. It is not an actual > coordinate in space time, for that you use coordinate time. All things > travel equal distances through space time in equal coordinate times, but > not all things travel equal distances through proper time (clock time) in > equal coordinate times. It is when the coordinate times are equal that two > things can interact. > > > > Since the spacetime t coordinates are different WHEN are they together? > > > Their coordinate times are equal. > > > Certainly not in a simultaneous clock time as proved by their differing > clocks. > > > Right, their proper times are different. > > > 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. > > > They are together when their spatial coordinates: x,y,z and coordinate > time t are the same. You are right this t is not the same as proper time. > > Your conclusion that there must be a global present for this to work is > unneccessary. > > Jason > > > 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 [email protected] <javascript:>. > To post to this group, send email to [email protected]<javascript:> > . > Visit this group at <http://groups.google.com/group/everything-list> > http://groups.google.com/group/everything-list. > For more options, visit <https://groups.google.com/groups/opt_out> > https://groups.google.com/groups/opt_out. > > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
