Re: SR cannot determine Contraction

"Dono" <sa_ge@xxxxxxxxxxx> wrote in message
news:b7838021-5d8f-4319-9451-4db7f9612dab@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Feb 24, 6:21 pm, "Artful" <art...@xxxxxxxxxx> wrote:

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.
Umm, no. This is unphysical, as explained earlier.

Umm, yes .. it is a physical effect that is being described in that thought
experiment .. its not some sort of optical illusion.

At a fast enough speed wrt the barn, a moving pole would physically fit
within the 'shorter' barn at a given instant.

Objects that undergo length contraction do really occupy less physical space
in the frame of reference where the are moving. The measured length .. ie
the spatial distance between one end point and the other of the moving rod,
at any given instant in that frame .. is shorter than the rest length of the
rod. It occupies less space in that frame. This is real and physical (in
the frame of the observer).

Many people have trouble coming to terms with what length contraction (and
time dilation and relativity of simultaneity) mean, you appear to be one of
those people. Most seem to think it is a physical effect on the rod itself,
making the rod squash up and shrink (ie within the rest frame of the rod,
and like in LET), whereas you are at the other extreme who don't think
anything really happens at all and that it is all some sort of illusion.
This is very sad, because you seem to have a reasonable grasp of other SR
related issue.

I'm sure you'll get it once you come down off your ego horse.



.

Relevant Pages

  • Re: TOM ROBERTS - Dono is confused, please help him out (was SR cannot determine Contraction)
    ... the long axis of the rod) in some inertial frame of reference, its length taken at some given time within the frame of reference will be shorter than its length when at rest .. ... pole-and-barn thought experiment where as some given time in the FoR of the barn, the pole in motion is fully within the barn, even though the rest length of the pole is longer than that of the barn. ...
    (sci.physics.relativity)
  • Re: The Emission Theory of Androcles
    ... A rod is moving at v away from Observer1. ... distance between its endpoints at any given time in O2's frame. ... endpoints at any given time in O2's frame is shorter. ... physics. ...
    (sci.physics.relativity)
  • Re: On the physicality of length contraction
    ... In one frame, the explanation is that the pole really is shorter than ... the barn, and the doors are shut simultaneously. ... the explanation is that the doors are shut ...
    (sci.physics.relativity)
  • Re: The Emission Theory of Androcles
    ... A rod is moving at v away from Observer1. ... distance between its endpoints at any given time in O2's frame. ... endpoints at any given time in O2's frame is shorter. ... That sort of 'drivel' is called good physics. ...
    (sci.physics.relativity)
  • Re: A robust demonstration for length contraction
    ... That's different to the way things are usually stated, where the rod is at rest in the S' frame, and the S frame is that of the observer who wants to know the length of the rod that is moving relative to him. ... If translate the formulas to the familiar pole and barn scenario, and use your convention that the pole is at rest in the S frame, and the barn in the S', then what setting dt=0 means is how long does the barn appear to the pole. ...
    (sci.physics.relativity)