The thread was called "Just a Second" and had a lot to do with absolute time. As I was reading this, I couldn't help but visualize a Pro-Wrestling style match.
Here is the chronicle of the actual thread.
What follows is my take.
Nathan Fenenga Yospe - firstname.lastname@example.org - University of Hawaii Dept of Physics Ken "Pretzel Boy" Seto - email@example.com - Credentials Unknown With appearances by: Graham Robinson - firstname.lastname@example.org - University of Glasgow "Mysterious" Murky B - email@example.com - ??? Steve "Left Field" Turner - firstname.lastname@example.org - Cornell University John Francis - email@example.com - Dept of Geological Sciences, CSU??
AND Nathan F. Yospe from the University of Hawaii Dept of Physics jumps into the ring to defend Graham! This is looking to be a great match!
No! Ken looks unscathed!
I think I see what you are saying about the universal clock, and in a limited sense I agree with you. Let me explain. From my perspective, I can establish the notion of "now" for my own location and all other locations. The fact that light takes time to travel from place to place is a minor inconvenience, in that I can't really say that something happened at all until I get the news, and by then the "now" during which it happened has gone by. But I needn't let that worry me, I can simply back-date the news an amount equal to the distance it traveled divided by the speed of light. The distance, of course, will be subject to some dispute, but for my own purposes, I can establish it easily by bouncing a light ray off it and measuring the transit time (using my own clock).
If I can convince everybody to use my clock and my interpretation of distances, I will have succeeded in establishing a universal time. If everybody uses it to measure times for all purposes, the the absolute time and *now* that we desire will have been achieved. There will be some problems with this system, though. Suppose I send someone to another planet to get some stuff for me, and during this trip he will travel at a reasonable fraction of the speed of light. Then as you pointed out, this motion will affect his physical processes. Suppose my envoy wants to get some sleep, and knows that 7 hours will do the trick. I can construct a portable clock for him which will read the "universal" time by using one of the "flawed" clocks which relies on some periodic physical process, and correcting it according to how fast it is moving, and how far away it is from its original location. My envoy will have a very difficult time using this clock, because it will speed up and slow down in an annoying fasion depending on how fast he decides to go.
So, he cannot use it to correctly gauge how long to sleep, or how long to cook an egg, or when his laundry will be done. He can't even tell how much longer the trip will take without doing some calculations. In fact this clock will not be useful to him in any way, because if he is an independent spirit and decides to take a look at *my* clock at home base (using a large telescope) and correct for the time delay in the same way he is accustomed to seeing me do it, he will be shocked to discover that his clock and the home base clock disagree! This discrepancy will resolve itself as he approaches closer and closer to the home base, but nonetheless they will disagree.
Now one might say that it is a bit selfish of me to define the universal time according to my own point of view, and indeed, it seems to somewhat diminish the aesthetic appeal of the whole idea. It would be much better if we were all just *given* one of these portable absolute clocks, without any mention of where it came from. Absolute time should be like this after all.
Unfortunately, the problems with these clocks will persist! they will appear (to us) to run at different rates, and they will be of no use in scheduling meetings or officiating the all-universe olympic games. The variations in the rate of passage of 'universal time' will make them practically useless! Unless, or course, you and everybody you know are in very nearly the same frame of reference. If you never travel very fast with repect to anybody that you might talk to, then the subject of these variations would never come up, because they would be too small to notice. In fact, 'couterfeit' universal clocks could infiltrate the community, ones which are not actually corrected, but rely simply on some periodic process, for example a swinging pendulum.
These counterfeit clocks could easily be mistaken for clocks which read absolute time. The difference would not be discovered until someone or something accelerated to a speed large enough for it to be noticed.
In essence, this is exactly what has happened in our community here on earth. We mistook our clocks for absolute clocks, and when it was found out that they are not, there was alot of commmotion and disbelief and in the end we will slowly get used to it.
The situation is similar in General Relativity. Rather than assuming that space is curved, one can instead assume that space is flat, but there are universal forces acting on all sources of energy and momentum. Just as the "absolute rest frame" of the ether theory is undetectable, the "flat space" of this theory is undetectable, and this theory ends up being equivalent to General Relativity.
Ken "Pretzel Boy" Seto - 8 Nathan Fenenga Yospe - 14Nathan Remains Champion of the WPWA! (World Physics Wrestling Association)
Date: Wed, 8 Apr 1998 22:57:04 -1000 From: Nathan F Yospe
X-Sender: yospe@uhunix1 To: firstname.lastname@example.org Subject: Just saw the play-by-play MIME-Version: 1.0 Interesting. Very interesting. Brings back memories, it does. -- Nathan F. Yospe - Aimed High, Crashed Hard, In the Hanger, Back Flying Soon Jr Software Engineer, Textron Systems Division (On loan to Rocketdyne Tech) (Temporarily on Hold) Student, University of Hawaii at Manoa, Physics Dept. yospe#hawaii.edu nyospe#premier.mhpcc.af.mil http://www2.hawaii.edu/~yospe/