While MacM's thread asking about length contraction was closed until he decides to resume discussion, it did seem to bring up other interesting questions. In particular it appears to me that not all "mainstream proponents" (for lack of a better word) have the same concept of length contraction. I would like to explore this in more depth.
I was taught in high school that a moving object is contracted in the direction of motion, and that this has been proven experimentally. However, a couple posts (1, 2) suggest mainstream physics does not believe this anymore. In fairness, both posts are from the same user, so this may just be a misunderstanding. But none of the other mainstream posters commented on this or corrected this, which makes me wonder what is going on.
So in summary, the topic of discussion here is:
Does mainstream physics still believe that a moving object is contracted in the direction of motion, and that this has been proven experimentally?
Your comments are much appreciated.