# Bell's spaceship paradox - Special relativity

It appears clearly in frame S' that the length of the rope is longer than at rest in that referential, therefore it breaks. Nevertheless, I can't see why in the S frame the rope should break as for the S frame point of view, the length of the rope stays the same (L).

Can someone explain how in this diagram the S frame should conclude as well that rope breaks ?

The argument given in the text is that the rope moves so it experiences Lorentz contraction from a frame S point of view. But this does not seem to appear on the diagram, or does it ?

• Possible duplicate: physics.stackexchange.com/questions/244315/… – WillO Oct 19 '16 at 12:33
• @WillO It's linked with the duplicate you suggest, but my specific question is about the included diagram: how does frame S conclude that the rope should snap in that diagram ? And if the information is not there, why ? – Santa Oct 20 '16 at 7:50
• I still think it's essentially the same question. The other question basically asks "Can an observer in frame $S$ explain the snapping without using relativity?", or in other words "Can an observer in frame $S$ explain the snapping without referring to frame $S'$?". Your question asks pretty much exactly the same thing. – WillO Oct 20 '16 at 14:35
• In this question, I'm not asking to explain the snapping without using relativity. I'm asking why in the diagram, it is obvious on the frame S' point of view the rope is snapping when I can't see in the diagram why it should be obvious from frame S. I know believe the information is just not there in the diagram: the contraction of a train "normally" accelerating is not represented and should turn out to be a "smaller" train from a frame S point of view. So my answer seems to be "the information is not in the diagram". – Santa Oct 21 '16 at 7:57