Re: SR cannot determine Contraction

"N:dlzc D:aol T:com (dlzc)" <dlzc1@xxxxxxx> wrote in message
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Dear Artful:

"Artful" <artful@xxxxxxxxxx> wrote in message
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"Dono" <sa_ge@xxxxxxxxxxx> wrote in message
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I know the paradox, this simple exercise doesn't
support your view.

Yes .. it does. If the pole was not taking up less
space in the barn's frame of reference, it would
not fit inside the barn.

There is no "barn's" frame of reference. In the rest frame of the barn,

You just said there wasn't one.

an observer in the front of the barn and an observer in the back of the
barn will not agree that both doors were closed "simultaneously".

They certainly can. Simulaneity is well defined in SR

It is very important that you not imagine you can have instantaneous
signalling from the front to the back of the barn.

You don't need it. You can have a signal sent from the centre of the barn
to the two equidistant observers. Anyawy .. this is not about the physical
ability to construct a real and literal pole-in-the-barn experiment. It is
about the fact that, in SR, a moving object occupies less 'space' in a given
frame of reference at a given time than it does if it were at rest.

The pole is "really" contracted,

Yes .. it is. In the pole-and-barn for a ceratin time, the pole is entirely
within the barn (whether or not you close the doors), even though the barn
has a shorter rest length than the pole.

AND it is entirely a matter of perspective.

Yes, it is. Reality is what we measure.


.

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