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From: jimc@haddock.UUCP
Newsgroups: net.physics
Subject: A Question on Time Dilation
Message-ID: <15000004@haddock.UUCP>
Date: Sat, 1-Jun-85 13:20:00 EDT
Article-I.D.: haddock.15000004
Posted: Sat Jun  1 13:20:00 1985
Date-Received: Mon, 3-Jun-85 00:38:31 EDT
Lines: 27
Nf-ID: #N:haddock:15000004:000:1350
Nf-From: haddock!jimc    Jun  1 13:20:00 1985


I am very puzzled over something in Einstein's theory of time 
dilation, that is, that time passes more slowly for objects in 
motion then for objects at rest.  Here is my understanding of th 
theory and how Einstein arrived at it.  There has to be something 
wrong with my thinking somewhere, though this understanding is 
based on the book *The Universe and Dr.  Einstein*, by Lincoln 
Barnett, a book which Einstein himself heartily praised.  

Einstein's theory about time dilation is based on the assumption 
that the speed of electromagnetic radiation is constant 
throughout the Universe, whether or not the object emitting the 
radiation is in motion.  Here is an example which may clarify why 
Einstein arrived at this assumption: suppose an object that is 
travelling through space at a rate equal to 75 percent that of 
light and that it was emitting a light ray in the same direction 
it was travelling.  For that light ray's speed to remain at C, 
the rate of time passage for the object must decrease 
proportionally.  

Yet, I find myself still asking this question:  what about a light
ray being emitted in the opposite direction?  Can't it just as easily
be said that time is speeding up for the object under these circumstances?
I can't believe Einstein wouldn't have thought of this!

			Jim Campbell
			...!ihnp4!ima!haddock!jimc