[Vision2020] Time Dilation: T' = T  1-(v/c)2

Tbertruss at aol.com Tbertruss at aol.com
Sat May 7 12:25:30 PDT 2005


Donovan et. al.

Jeez, what's got into you?  Really!  Is this a joke, or what?  You're 
starting to sound like the advocates of teaching creationism as a scientific theory 
in the public schools who state over and over that evolution is not a "fact" 
but an unproved theory.

I wrote "time travel is not just a possibility, but a verified scientific 
fact."  This means that experiments have been conducted to gather facts to verify 
the predictions of the equations of time dilation from Relativity.  
Scientific facts that verify the truth of theories is how science operates: no 
empirical facts to validate a theory, a theory remains just a theory.  Replication of 
experimental findings that verify theories is the cornerstone of how science 
connects theory with fact.  Any scientist who wishes to demonstrate his theory 
is more than just a theory conducts experiments to gather facts regarding the 
predictions of his theory in a manner that documents the arrangement and 
results of the experiments with such detail and precision that any other scientist 
who wishes to investigate the predictions of the theory can do so via 
replicating the experiment.  

If we find empirical facts that verify the theory of Relativity, it is more 
than a theory, it has empirical verification.  Of course new theories may come 
along that are more powerful or inclusive, or the universe may change how it 
operates.

But you are spouting nonsense.  Theories in science do receive verification 
with facts.

Please educate yourself!  The U of I failed.  Now go to your room and study 
the text and equations below:

http://www.hcc.hawaii.edu/~pine/book1qts/chapter7qts.html

Time Dilation   

The idea that time can vary from place to place is a difficult one, but it is 
the idea Einstein used, and it is correct -- believe it or not.  Richard 
Feynman
 
    Einstein realized that if the laws of nature are the same from every 
standpoint, then for physicists to be able to continue to do physics in a universe 
of relative moving objects, they will need to mathematically transform how 
time will be viewed from different reference frames. Einstein used a 
mathematical equation called the Lorentz-Fitzgerald transformation. It worked perfectly. 
The equation is a relatively simple algebraic relationship:
                
T' = T  1-(v/c)2 

In this equation, T' is the time of an event in a reference frame moving at a 
velocity v in relation to an observer whose time is T. The small c is a 
constant, the speed of light. Let's see how it works. Suppose in our train example 
that X and Y both possessed clocks that some time ago were synchronized when 
the train was stationary. Y then moved at a normal speed, very slowly compared 
to the speed of light, to the point between A and B. Suppose at a prearranged 
time X departs and that for the last 15 minutes by Y's reckoning the train has 
left the initial starting point and been moving to the point where Y is at an 
average speed of three-fifths the speed of light.(5) What time will the clock 
of X read according to the Lorentz transformation? If we plug in the data, 
                                                     
T = 15 and v/c =3/5, so T' = 15 1-(3/5)2 

When X passes Y, X's clock will show that the train has been moving for only 
12 minutes! From Y's point of view, X's time has slowed down relative to Y. It 
would not just seem to slow down; real physical measurable effects would be 
seen when X and Y compare their clocks. If X and Y both lit cigars at the 
prearranged time, X would find that his cigar has burned less than Y's as they pass 
each other.(6) X will experience nothing unusual. The laws of nature are the 
same, including that for burning cigars. For X everything will appear normal 
including the movement of his clock. At no point will X's clock suddenly slow 
down dramatically. It will appear normal. Likewise, Y will not suddenly see the 
last few minutes of his experienced 15 minutes fly by at a different rate. 
His clock will also appear normal. Nor will either notice anything strange about 
the rate their cigars burn. Time slows down in reference frame X only in 
relation to reference frame Y. Within their respective reference frames everything 
is normal.  
 
If my home and office were separated by many light years, my home (depending 
on the distance and the speed of my travel) could be many thousands of years 
in the future when I arrive at work.

The testimony of our common sense is suspect at high velocities.  Carl Sagan
    
This slowing down of time of a reference frame relative to another reference 
frame is called time dilation. As unbelievable as it may seem, it is one of 
the most accepted scientific facts of our time.(7) It has been tested in 
numerous ways. Very precise atomic clocks have been synchronized and then compared 
again after one was flown around the world on a jet airplane. The clock on the 
fast plane slowed down in relation to the clock that stayed on the ground. A 
similar test was conducted using one of the U.S. space shuttles with the same 
result. Scientists now apply time dilation routinely in sophisticated laboratory 
situations. In the billion-dollar particle accelerator laboratories all over 
the world, physicists can keep special particles of matter "alive" far longer 
than would normally be expected because of the time dilation effects that 
result by accelerating particles close to the speed of light. In this way special 
forms of energy can actually be "stored" for use in crucial experiments. As 
far as most physicists are concerned, time dilation is a fact of nature. Rather 
than the large fishbowl of time implied by common sense and Newtonian science, 
Einstein has revealed to us a "chunky" universe of relative reference frames 
and times. There is no universal "now"; there are only simultaneous events in 
relation to local reference frames. Trains, of course, do not move at 111,600 
miles per second (three-fifths the speed of light), and hence, it is easy to 
see why time dilation effects are not noticed by common sense. Theoretically 
spaceships could. What kind of astronautical scenarios are then possible? 
Suppose we know twins 20 years of age, one an astronaut who will take a space voyage 
that will take 20 years by Earth time. Suppose that the astronaut twin 
averages in his rocketship a speed of three-fifths the speed of light. How old will 
each twin be when they meet again 20 Earth years from now? Using the time 
dilation equation we have:
             
T = 20 1- (3/5)2+ 20, which would equal 36. 

The twin who stays on Earth will be 40 years of age. The twins will no longer 
be the same age! What applies to time will also apply to space. Just as the 
twins would discover that there is not one time that marches along in a strict 
Newtonian fashion, so they would also discover that there is not one large 
fishbowl of space where the distance between two points is the same for every 
observer. Just as time slows down, so space contracts. Because of the speed he is 
travelling, between the points of his departure and arrival the astronaut 
twin will measure his voyage as 14 trillion miles shorter than his twin would 
with instruments on Earth.  

Traveling at great speed slows our histories down from one point of view, and 
allows us to speed to the future from another.

    This example is not science fiction. Time dilation has been shown 
repeatedly to be a fact of nature; this effect on an astronaut would indeed happen. 
If it is so hard to believe, it is because we have difficulty realizing that 
the things we take for granted on Earth do not necessarily apply throughout the 
cosmos. With Einstein, the cosmos is now our laboratory, and we must adjust to 
the conditions of this new laboratory. Stranger still, consider this 
scenario. The star Vega, a star like our Sun and a possible candidate for a planetary 
system, is approximately 32 light-years away. Suppose in the near future a 
30-year old woman astronaut, who has a five year old son, went on a space voyage 
to explore this star, averaging the colossal speed of 99.5 percent the speed 
of light. At such a speed it would take her about 64 1/3 years Earth time to 
make the trip. When she returned, her son, remaining on Earth, would be into his 
69th year. Both would be in for a great shock. The 69-year old son would 
embrace his long-awaited 36 1/2 year old mother! Their personal histories would 
have seemed to be normal in all other respects, but it would now be clear that 
traveling at great speed slows our histories down from one point of view, and 
allows us to speed to the future from another. If such a voyage were undertaken 
in the year 2000, the mother astronaut could get to the year 2064 in a little 
under 6 1/2 years. An event that required only 6 1/2 years for the mother, 
required a little over 64 years for the son. In our train example, an event that 
happened before another event for one observer (lightning striking point A 
before point B for X ), happened at the same time for another observer (Y). It 
would also be possible then for another observer moving in the opposite 
direction of reference frame X at a great speed to record the lightning striking at 
point B first. Thus, one person's past could be another's future. Would it then 
be possible for the mother to return at an age before her son was born? Not 
according to Einstein's theory, not if the speed of light is a law of nature. 
Because the speed of light is an absolute that cannot be exceeded, causal 
connections, such as mothers causing the birth of babies, are preserved in their 
normal sequences. According to Einstein's theory, the measurement of "before" 
and "after" may involve a wide latitude, but the order of events will not be 
changed. The time between the mother's "before" and "after" of her space voyage 
is much shorter than that experienced by her son, but both would experience her 
leaving before she came back. If and only if the speed of light is exceeded 
will the sequencing of causal events be changed, and it is a basic consequence 
of Einstein's theory that the speed of light cannot be exceeded. According to 
the theory, it would take an infinite amount of energy to accelerate any 
object (even an electron) up to the speed of light and thus require more than an 
infinite amount of energy to exceed the speed of light.(8)     

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V2020 Post by Ted Moffett

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