Are there no professional physicists that moderate this area of the forum to respond to the false claim that it is impossible in theory to devise an experiment for humans to optically observe Lorentz contraction ?

If there were competent professionals moderating this area they would immediately tell you exactly what I was saying. Length contraction is a direct consequence of defining simultaneity in the particular convention called special relativity.

Your response is a perfect example of the basic problem I am complaining about in the previous post. You have to understand it is almost impossible to say what do they mean by what they are saying in most papers about relativity because of basic ambiguity of our language. In the paper you are referring to, they may even themselves be interpreting their result as an optical view of length contraction. Yet, in actual fact their interpreted result must be directly based on the

**convention**of establishing simultaneity via isotropic C in their lab frame.

Don't get me wrong though, no one is claiming that relativistic definitions are the same as newtonian definitions. It would be pretty naive to interpret this thread as asserting so. Newtonian definitions are far less accurate than relativistic definitions, and relativistic definitions are assumed to be exactly valid in every junction of this thread (at least in mine and DD's posts, quite clearly). That is to say, length contraction is seen as a valid

**representation**of reality; and as such it is something that must exist in any equally valid representation in some form or another.

**It may or may not be called length contraction however.**The fact that a certain logic can be represented in multitude of ways is under the focus here; that is why it is called "a representation of" reality.

So, in that paper, do you think they are asserting that their lab frame is a preferred frame, i.e that things moving in their lab frame are actually length contracted?

Or don't you think they understand the principle of relativity, and so they also understand that things are length contracted in terms of how they must be represented in our inertial frame. But at the same time, our choice of representation doesn't actually cause any physical changes to them?

You have to understand the critical difference here; It is entirely possible that objects actually length contract in ontological sense; meaning there is a preferred frame in which things have their "maximum length". Whether or not that is true, is impossible to prove because little thought would reveal every frame would appear observationally identical anyway; at least as long as the symmetries apparent in Maxwell's Equations are valid. Note that Newtonian definitions would not yield those symmetries as valid!

The fact that Newtonian view and Maxwell's Equations did not match was exactly the "paradox" that allowed Hendrik Lorentz to derive Lorentz transformations, which was effectively the first representation of the very logic we now call special relativity (and it does represent its own version of length contraction of course). The only difference is, Lorentz' representation form did not imply the principle of relativity for the speed of light.

All that Einstein did at that point was he took Lorentz' result, and applied principle of relativity to C*, and worked out the math from there.

That history is why it is still called Lorentz Transformation, not Einstein Transformation.

And what Hermann Minkowski did from that point on is he proposed an ontological construct of space and time that would behave how Einstein's version behaved. That is why it's called Minkowski spacetime, not Einstein spacetime.

And somewhere along the way, everyone forgot that all this was just a representation form of a logic that was required to paint a self-consistent picture of Maxwell's Equations! Meaning, relativity is a valid transformation mechanism between different inertial frame representations of the same electromagnetic apparatus. Furthermore it is a representation in which the inertial frames can all be seen as equally valid, by our free choice of using that particular transformation. And in doing so, each frame must represent moving things as length contracted, in order to paint a coherent picture between different frames.

The basic argument I'm making is simple, you have to understand the difference between actual reality, and a valid representation of reality. If you confuse the two, you will erroneously think the validity of SR means rather many things that are actually just an arbitrary belief towards a preferred representation form of the formalism behind SR.

This really is a great topic, I hope there was more people thinking about these things because it does go a fair bit deeper than this...

-Anssi

* It occurred to me that this comment may not sink in to the reader if they are not aware of the fact that the principle of relativity to C can be applied to Lorentz result without changing any observational property. Lorentz' result was known to be observationally valid by that time, and anyone who understands his logic, and understands why simultaneity of separated events cannot be proven (see my previous post), also understands why relativistic C doesn't change the "truth" of the equations. Surely Einstein understood this fact just as well as anybody, and I believe that is exactly why he has commented that he was absolutely convinced he was "right" before any experimental results; meaning that in observational sense, he was just as "right" as any other representation of the same relationships could possibly be.

**Edited by AnssiH, 26 January 2014 - 11:42 AM.**