On the interpretation of a spacetime diagram

[GrayGhost]

You are correct that Lorentz considered the Fitzgerald contraction a physical deformation of the electron field about the atom. They assumed the body contacted in an aether that does not.

Einstein's length contraction is completely different, yes. If an aether exists, it doesn't matter at all per SR. Consider 2 bodies of the same frame, one in front of the other separated by some proper distance s. Now, assume yourself in motion wrt said bodies, with velocity vector parallel wrt the center-line connecting the 2 bodies. While viewed in motion, not only do the moving bodies length-contract, but all the space between them (and within them) does as well. IOWs, it's not that the moving body contracts in a space that does not ... but rather that the way in which space and time are measured changes with a change in one's own state of motion. This is why you remain unaffected when (say) 10 moving observers measure your length differently. Yet, their measurements are correct, and quite real. Theoretically, with sophisticated enough measuring systems using lasers, light signals must reveal what the math of SR predicts for any of said 10 moving measurers.

GrayGhost

 

[bobc2]

You are correct that Lorentz considered the Fitzgerald contraction a physical deformation of the electron field about the atom. They assumed the body contacted in an aether that does not.

Einstein's length contraction is completely different, yes. If an aether exists, it doesn't matter at all per SR. Consider 2 bodies of the same frame, one in front of the other separated by some proper distance s. Now, assume yourself in motion wrt said bodies, with velocity vector parallel wrt the center-line connecting the 2 bodies. While viewed in motion, not only do the moving bodies length-contract, but all the space between them (and within them) does as well. IOWs, it's not that the moving body contracts in a space that does not ... but rather that the way in which space and time are measured changes with a change in one's own state of motion. This is why you remain unaffected when (say) 10 moving observers measure your length differently. Yet, their measurements are correct, and quite real. Theoretically, with sophisticated enough measuring systems using lasers, light signals must reveal what the math of SR predicts for any of said 10 moving measurers.

GrayGhost

Nice summary of the situation, GrayGhost.