Why "light clock" is flawed. I have been considering this thought experiment for some time, and the principle seems "broken". I'm wondering if by playing devil's advocate you can show me what is going wrong. -In SR, the light clock was used to predict time dilation in a "moving" object. -According to the Twin Paradox, two distinct frames of reference in different inertial motion would see time dilating in the other one, because all motion is relative. -The counter argument to this is that the frames of reference are not identical, because in the Twin Paradox, the Twin flying away from earth accelerates and is not in constant inertial motion. -We therefore can't use SR to answer the Twin Paradox, we have to use GR. -Using a GR thought experiment, the Light Clock would no longer function if acceleration is great enough. The acceleration would cause the beam of light to bend outside the light clock, even from the light clock's frame of reference.