World Science Scholars

32.3 The Pole in the Barn Paradox

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    • Consider a version of the Pole-in-the-Barn ‘paradox’ in which a bundle of dynamite is hooked up to explode if the pole fits inside the barn. Does this complicate the proposed resolution? Do we now have to deal with a more urgent paradox in which observers at rest with respect to the barn say it’s been blown to pieces while those at rest with respect to the pole say it hasn’t?

    • This is actually a scenario I have a hard time to understand. Let’s consider the case used in this section’s problems where the lengths at rest are 10 feet for the barn and 15 feet for the pole and the relative speed 12/13 the speed of light. Each team arrives at a different conclusion as to whether the pole fits or not in the barn. However, as they must agree on events occurring or not, explosion or no explosion, how can they reconcile? Is it that each team has to compute a correction to consider what happens when both the barn and the pole are at rest? But then, each team must be living in a transformed world and must always make corrections to find what the motionless world is. Patrick

    • No explosion because the proper lengths of the pole and barn are such that the pole will not fit physically. The observed lengths are not the physical lengths and its the physical lengths that would be relevant to effecting an explosion event. This reminds me of Schrodingers cat!

    • That dynamite pole makes it seem like there’s real paradox in here. What would’ve Einstein said to this dynamite thingy? I don’t know…

    • The statement is that the explosion will happen “if the pole fits inside the barn” But we have to ask from whose perspective it fits and the physics would suggest that it must be from the perspective of the rider on the pole because the sensing mechanism to trigger the explosion must in effect observe if the pole fits and we know from the math that the observer on the pole will never come to that conclusion – hence no explosion.

    • No

    • It depends where the mechanism is mounted. If on the barn, it sees the contracted pole and sets off the explosives. If on the pole, it sees the contracted barn and does not trigger. If elsewhere, the motion of the mechanism is important in determining the outcome.

    • Well as it has already said that pole is larger than Barn, and this notion of pole fitting inside the barn is due to asynchronous nature of time as per both the observer so no urgent paradox is there.

    • The pole will explode from both perspectives. But those on the pole will say that the explosion was unfair

    • no explosion

    • i believe the outcome would depend on their own perspectives

    • There will be no explosion. The reason is that the dynamite also rides on the pole. Hence, it’s clocks are same as the pole’s. Therefore, the machinery which sees that whether the pole has fit inside the barn or not, will notice that both the ends of the pole were not inside the barn simultaneously.

    • I would agree with those who say it depends on the “perspective” or mounting, of the explosive device, or perhaps more realistically the sensor.

    • No paradox here. There is only one dynamite. And it will or will not explode depending on its perspective. From its perspective (the pole perspective) it doesn’t fit. So it does not explode. And the observer at rest (the barn perspective) will not see the dynamite explode.
      If there are two dynamites (at rest relative to the barn and moving with the pole), the first one will explode and the second one won’t. But it’s absolutely normal, so no paradox here either.

    • No explosion since the pole’s rest length doesn’t fit in the barn. Both pole and barn observers must agree on an event occurring or not occurring. Gracie understands that the barn didn’t explode because her clocks are out of synch, per the dynamite trigger perspective, when measuring the ends of the pole both inside the barn.

    • There’s no contradiction. There is only one discrete outcome, which is either the bundle explodes or it doesn’t, regardless of whether they agree on that fact or they don’t.

    • Polebarn perspectives and paradoxes at different velocities allow for space dilation of the pole.

      Reference points inside and outside the pole barn allow for recognition of when dilation occurs.

      The paradox of the pole both able to fit and not fit allows for SRT observations on Lorentz equational accuracies.

      Clearly the pole is under the Lorentz transformation while the barn is isometric, non- moving.

      The reality of events says that faster pole delivery allows the pole inside, but once inside, if it stops, it brings down the house if multiple poles enter the polebarn only to elongated after entrapment.

      So management gets angry when the dynamite is not pole extension itself but is the same effect.

      Larel and Hardy could not have a better skit. How did that happen? is answered by the Lorenz effect.

    • well no because the pole never did fit in the barn it only appeared to.

    • It is just that their perception of the length of the pole and the barn are changing because of the effect of Lorentz contraction but it will simply depend on the fact that whether the pole fits or not into the barn when both of them are observed in a common frame of reference.

    • In the scenario you described, the presence of the dynamite attached to the pole does complicate the situation, introducing a potential paradox. Let’s analyze the situation from two reference frames: one at rest with respect to the barn and the other at rest with respect to the pole.
      From the frame at rest with respect to the barn, the situation appears straightforward. The pole fits inside the barn, and the dynamite will trigger and explode, resulting in the destruction of the barn. Therefore, observers in this frame would conclude that the barn has been blown to pieces.
      From the frame at rest with respect to the pole, the situation is different. Since the pole is stationary in this frame, it doesn’t fit inside the barn, and the dynamite would not be triggered. Therefore, observers in this frame would conclude that the barn remains intact.
      Now, we encounter a paradox, observers at rest with respect to the barn claim that the barn has been destroyed, while those at rest with respect to the pole claim that it remains intact. This apparent contradiction arises because we are considering two reference frames simultaneously.
      The resolution to this paradox lies in understanding that the triggering mechanism of the dynamite is frame-dependent. The dynamite’s detonation is synchronized with a specific reference frame. If we consider the frame at rest with respect to the barn as the reference frame synchronized with the triggering mechanism, then the dynamite will explode and destroy the barn. On the other hand, if we consider the frame at rest with respect to the pole as the reference frame synchronized with the triggering mechanism, then the dynamite will not explode, and the barn will remain intact.
      The key point is that we cannot simultaneously synchronize the dynamite’s triggering mechanism with both reference frames. The resolution of the paradox depends on selecting a specific reference frame that governs the synchronization. By doing so, we establish a consistent cause-and-effect relationship and avoid these contradictory conclusions.

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