Re: Our present difficulties.

On May 24, 12:36 pm, "Gerald L. O'Barr" <glob...@xxxxxxxxx> wrote:


O'Barr comments:
But I have studied. And you know that I have
studied. And I have found out that you believe in
stupid things. No real physical object can be both
going faster and slower than another physical object
at the same time. No real object can do such an
impossible thing.

Gerald, please reconsider this statement. You surely did not mean it.
Let me give you a basic example that can be found in any introductory
physics text.

There are two trains and the passengers of the two trains are watching
outside the windows at the same events transpiring. There is a car on
a nearby highway nearing a truck. From the perspective of one train,
the truck is traveling at 20 mph (some on the train would say that the
truck is moving 20mph faster than the train is going, but as we'll see
in a moment, that too is an arbitrary statement) and the car is
traveling at 45 mph, and so the car is approaching the truck at 25
mph, with the car traveling faster than the truck. But the passengers
on the other train, which is moving at 50 mph relative to the first
train, describe the car and the truck differently. Now the car is
moving at -5 mph, and the truck is moving at -30 mph. Here again the
car is approaching the truck at 25 mph, but with the truck moving
faster than the car. So you see, it is entirely possible for the car
to be faster than the truck and the truck faster than the car, simply
by changing reference frame. This has been true since Galileo and has
nothing to do with Einstein.

Now you may say, "But that's not fair! The trains are moving and so
the motion of the car and the truck are the compositions of their
motions and that of the train. You must have a stationary reference by
which to measure the motions of the car and the truck!" To which I
would ask, What stationary reference do you propose? Surely not the
surface of the Earth, because that is certainly moving. Certainly not
the center of the Earth, because that too is moving. What measurably
stationary reference would you use to truly characterize the motions
of the car and the truck, to find out which one is truly faster than
the other?

PD

.

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