[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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