Dear David Smith:
You have said,
If both frames are moving the same speed, but different directions, they
will both age the same.
So, like the person who wrote the account of the twin paradox in the FAQ,
you do believe that time dilation affects the rate of aging.
The formula for time dilation is a function of velocity. If I am moving at a
given velocity with respect to you, then you are moving at the exact same
velocity with respect to me. To whatever extent there is time dilation and a
reduction of aging, it is predicted to be the same for you as for me,
because v is the same, and the formula is a function of v. You see me in
slow motion and I see you in slow motion, so both our ages are reduced by
the same amount.
Is that not the case?
Stephen
(formerly)" dlzc1.cox@net wrote in message
news:uY%nb.123151$gv5.60210@fed1read05...
Dear Stephen Bint:
"Stephen Bint" wrote in message
.. .
...
I started a thread about the twin paradox and cross-posted it to three
newsgroups. I am grateful to those who discussed it, even though it got
a
tiny bit personal at times 
I was frustrated by the account of the twin paradox in the FAQ for
sci.physics (http://www.faqs.org/faqs/physics-faq/part4/), because it
resorts to saying that there is assymetry in the situation. One twin has
undergone an acceleration and it is that one which is younger.
That cannot be the case, because time dilation is supposed to explain
why
a
light beam, travelling from floor to ceiling of a moving spaceship will
not
trace out its V-shaped path faster than c. Time must appear to be slowed
down or else the observer, looking through the window will see the beam
travel faster than c.
But if two people pass eachother on skateboards, watching eachother's
bouncing beams, they must both see time dilation in the other, or one of
them will see the beam going faster than c.
If you travel away from the Earth, you find that signals from the Earth
are
slowed as well. Just not as slowed as the Earth determines your signals
to
be.
Claiming an assymetry based on the acceleration histories of the
observer,
overlooks the fact that the time dilation must be real and identical in
both
directions at all times or else someone will see the bouncing beam going
faster than c.
If only one skateboard rider is younger, what did this younger one see,
the
other getting older? The beam going even faster than expected, much more
than c?
If both frames are moving the same speed, but different directions, they
will both age the same.
It baffles me, that intelligent people, capable of algebra, cannot see
that
the assertion that time is slowed in a moving frame is a symmetrical
assertion, because frames move relative to eachother, symmetrically.
Not true. The acceleration provides the asymmetry. The duration of the
velocity provides the difference. And the moving and non-moving frames do
not agree on the *amount* the other is affected.
Besides which, the formula for time dilation is a function of the
velocity
of the observed frame and makes no mention whatsoever of the
acceleration
of
either frame, before or while the calculation is made.
True. This *is* relativity. Absolutes are not at hand.
I was told again and again by several posters, "Do the math. Just plug
the
numbers into the formulas and it all works out just fine." These were
the
same people who want me to factor in acceleration, which is not
mentioned
in
the formula, because time dilation is purely a function of the relative
velocity, which is the same in both directions.
Plug the relative velocity of skateboarders A and B into the formula and
find out how much slower B's clock is, than A's. And how much slower A's
is,
than B's. I don't need to "do the math" to see that this formula is
telling
me two things which cannot both be true.
I suppose it depends on your definition of "working out fine".
Because I constructed my example with two moving twins, to force them to
face the symmetry, the defenders of relativity introduced a new twist:
acceleration causes time to speed up, cancelling out the age difference,
in
both skateboarders. This is an new addition to relativity. Einstein
never
said anything of the sort.
Time dilation doesn't much care about *direction*, only speed.
To say that acceleration makes time run faster, implies that if one of
the
skateboarders is accelerating, the time contraction due to acceleration
will
at least partially counteract the dilation caused by the velocity
(predicted
by Einstein), allowing the other to see the bouncing beam move faster
than
c.
Acceleration does skew the results with SR. SR is for use with inertial
frames.
Still, though frustrated, I thoroughly enjoyed the thread I started and
I
am
grateful to all of the people who had the patience to contribute. In
return,
I can only assure you that I will continue to post under the name
"Stephen
Bint", so as not to undermine your killfile strategies.
And may I say in conclusion, that trying to bring the sweet light of
reason
to the proponents of relativity, is like trying to bring salvation to
the
DAMNED.
Quite a lot of work you've cut for yourself. Not only do you know more
than anyone else, but you get to shine the light of revelation for us all.
Since you've committed the same sins as everyone else who has approached
relativity, including the big chip on your shoulder, my guess is there is
a
plank in your eye.
Try analyzing your two skateboarders from a third stationary frame? Tried
using addition of velocities?
David A. Smith