1
$\begingroup$

I'm reading a set of notes on special relativity and this statement was made at the end of the section on length contraction:

"This phenomenon is known as the Lorentz-Fitzgerald contraction. It is not the consequence of some force ‘squeezing’ the rod, but it is a real physical phenomenon with observable physical effects. Note however that someone who actually looks at this rod as it passes by will not see a shorter rod. If the time that is required for the light from each point on the rod to reach the observer’s eye is taken into account, the overall effect is that of making the rod appear as if it is rotated in space."

I understand that this is looking at a special case where we are physically observing an object as opposed to talking about mathematically what is happening but why would we observe the rod to be "rotated in space"? And along which axis would it appear rotated?

$\endgroup$
2

1 Answer 1

2
$\begingroup$

The apparent length contraction resulting from relative motion, which is given by the Lorenz transformations, is the effect that would seen by two stationary observers, one at each end of the interval being measured. The Terrell–Penrose rotation is a change to the perceived orientation of a moving object as seen by a single observer, and is a consequence of the different amount of time light takes to arrive at the observer's eye from the various parts of the moving body. The rotation is about an axis normal to the direction of motion. I suspect that the shape may appear distorted too, depending upon the angles which its various facets subtend to the eye.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.