Here is another train and platform example, offered to examine ghwellsjr's view equating what you see with what is real. Assumptions: Train has proper length 100. Platform has proper length 60. Train and platform are in relative inertial motion at 0.8c. There are two observers on the platform, Far (on the farther end of the platform from the train's perspective), and Near (on the nearer end of the platform from the train's perspective). Near and Far have watches, synchronized in the platform frame. Near's watch is an LED watch that flashes a signal with a time stamp toward Far as Near's watch records elapsed time. Simultaneously in the platform frame, the front of the train is at the far end of the platform, and the rear of the train is at the near end of the platform. Hooks at the front and rear catch Far and Near, like mailbags on the old mail trains. In the platform frame, both watches read 60 at this time. What happens according to Far? One theory: Far is hooked aboard the train and joins the train's reference frame when the far end of the platform and the front end of the train are aligned; Far's watch reads 60; but the platform is length contracted so that the near end of the platform is well ahead of the rear end of the train. For Far, the platform length contracts instantaneously toward him, so that Near contracts from being 60 away to being only 36 away. Near's watch runs backwards (the opposite of clock advancement that occurs in the usual acceleration examples, because the usual examples refer to planets or stars ahead of the accelerating object, not behind it as here). Stella inhabits an accelerated frame, and clocks in such a frame can . . . run slower or even backwards! The details depend not only on their motions, but also on their positions relative to Stella. . . Light from events below the plane can never reach you at all, and this prompts the plane to be called a "horizon". In fact, although you cannot know what is happening below this plane, it turns out that you can infer time below it is going backwards. See http://math.ucr.edu/home/baez/physics/Relativity/SR/movingClocks.html Then, Near's watch runs slowly (time dilation), so that by the time Near has aligned with the rear of the train and she is hooked aboard her watch is back up to 60. Near is younger than Far, as one would expect (Near's clock ran backwards, then ran more slowly than Far's). This theory seems to imply that Near's watch will send three sets of inconsistent time stamp signals to Far. First, just as Far's watch reads 60, Far will only have received Near's watch's flash time stamped 0 (because Far is 60 away). Thus signals time stamped 1-60 are still on their way toward Far. Second, Near's watch runs backwards, so the time stamps of each successive backward tick of the watch is sent toward Far. Third, Near's watch runs forward again, sending new successively forward time stamped signals. One could argue that there is a Rindler horizon when Far accelerates, preventing him from seeing Near's watch signals (as suggested in the quotation above). However, once he stops accelerating the horizon disappears, so any signals that occurred behind the horizon would be able to catch up to him. See, for example: Of course, this is not the same as a black hole’s event horizon in two very important respects. Firstly, it’s always possible to stop the spaceship accelerating, so this horizon’s persistence is a matter of choice, not physical law. http://gregegan.customer.netspace.net.au/SCIENCE/Rindler/RindlerHorizon.html A second theory: it is absurd to think that Far receives these multiple and conflicting sets of time stamped signals. Far receives the signal time stamped "0" just as he is hooked and joins the train, and thereafter he receives only forward ticking signals from Near. There is simply a gap in the set of time stamped signals that Far sees. This gap explains why Near ages less than Far (what you see is what you get). ghwellsjr, is this how you would analyze this example?