On 3/4/2014 11:19 AM, Jesse Mazer wrote:

On Tue, Mar 4, 2014 at 2:02 PM, Edgar L. Owen <edgaro...@att.net <mailto:edgaro...@att.net>> wrote:

    Jesse,

    You ask me to choose between 1. and 2.

    1. If B's proper age at this point in spacetime is T, then C's proper age 
at this
    point in spacetime must be T as well (i.e. their proper ages are 
"simultaneous" in
    the sense that they must reach the same age simultaneously).

    2. If B and C's worldlines both pass through a specific point in spacetime 
P, and
    B's age is T1 when she passes through P, while C's age is T2 when she 
passes through
    P, then B must be at age T1 simultaneously with C being at age T2 (i.e. 
whatever two
    specific ages they have at P, they must reach those two ages 
simultaneously, even if
    the two ages are different)


    First I assume that by "passing through the same point in spacetime" you 
mean that
    the worldlines cross at P simultaneously by the operational definition of 
no light
    delay.

    1. is true only in a SYMMETRIC case. In the symmetric case they would have 
the same
    ages as they pass through the same point P, but in that case they have the 
same ages
    during the WHOLE trip so no big surprise.


This isn't true. In the inertial frame of a third party passing by, B and C age at different rates in different segments of their world lines even though those rates integrate to the same total aging between their two meetings.

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 everything-list@googlegroups.com.
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/groups/opt_out.

Reply via email to