John, First, 2 substantial errors in your post below.
1. I stated that A began his trip from earth ORBIT, not from blasting off from earth's surface, so A's acceleration is 1g for the ENTIRE trip. But even if he blasted off from earth's surface at 2g that would have a negligible and irrelevant effect on his clock because it would only last for a few minutes. This is obvious because returning astronauts' clocks are different by a hardly measurable amount. 2. A's direction of acceleration doesn't JUST change if he decides to return. It reverses at the MIDPOINT of the trip so he can slow and stop at the galactic center. If he returns if would have to change it again at midpoint. So the points you make are not relevant to the discussion. However note also that the DIRECTION of B's acceleration is also continually changing relative to A's motion simply because the earth is rotating. So how does any change in the direction of acceleration of A have an effect but the continual change in direction of B's acceleration does not? Edgar On Saturday, February 1, 2014 12:46:17 PM UTC-5, John Clark wrote: > > > > > On Sat, Feb 1, 2014 at 7:57 AM, Edgar L. Owen <edga...@att.net<javascript:> > > wrote: > > > One might think it was the acceleration that slowed time on A's clock, >> BUT the point is that A's acceleration was only 1g throughout the entire >> trip which was exactly EQUAL to B's gravitational acceleration back on >> earth. So if the accelerations were exactly equal during the entire trip >> how could A's acceleration slow time but B's not slow time by the same >> amount? >> > > If A were going into space and accelerating upward off the surface of the > Earth at one g (32 feet per second per second), then he would be > experiencing 2g, one g from the Earth and one g from his continuing change > in upward velocity. > > > both = 1g throughout the entire trip >> > > No, not during the entire trip. And if the space traveler ever wants to > return to Earth to rejoin his friend so they can directly compare their > clocks then he's going to have to change the direction of his acceleration > by 180 degrees. So their clocks will not match because their travel > experiences were not symmetrical. > > John K Clark > > > > -- 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.
