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Can an airplane go through a quantum tunnel

  1. Apr 8, 2012 #1
    3 years ago when I lived in Jordan I met a Palestinian who believed that he had unified gravity with quantum mechanics. I knew enough about physics to know that that was a very hard thing to do but I didn't have the knowledge of course to tell if he was right. He certainly knew a lot about physics. I just looked up some experiments and some phenomena on wiki and asked him about them and he knew how all of the experiments were done and he had explanations for all of the bizarre phenomena that I had never heard of. I also knew another particle physicist from Saudi and I wanted the two to get together so that I could find out if the Palestinian was really on to something, I could never arrange that mostly because my desire to find out if he was as smart as he said he was, was not strong enough. Anyway, he wrote a 7 page paper about how he thought that this flight:


    had gone through a quantum tunnel. The wiki article cites the cause of the crash as follows:

    I of course didn't have the requisite knowledge to evaluate the paper but even with a common sense ability to understand argument I could tell that he didn't cite any facts about the airplane or the weather. It was pretty much just an assertion that the plane went through a quantum tunnel, then he listed an equation which I did not understand and that was it. I also remember that he thought particles going through a quantum tunnel could travel faster than the speed of light.

    My question here is do you think the guy was full of bs or not?
  2. jcsd
  3. Apr 8, 2012 #2
    what's a "quantum tunnel"?
  4. Apr 8, 2012 #3


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    Yes, it seems awfully likely, just on general principles. I don't have any specific physics to back that up but I'll be surprised if more knowledgeable folks here don't.
  5. Apr 8, 2012 #4


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    So far as I understand what this guy has said, seems total bs. The phrase quantum tunnel is actually a real one to describe real phenomenon. This involves particles 'tunneling' through a potential barrier to reach a lower energy final state (you can think of it as 'borrowing' energy for a moment to get over a tall hill before you give it back). But any extension of this concept to include a real 'physical' tunnel is almost certainly nonsense.

    Now, some popular accounts of quantum physics will tell you that if I am persistent enough and try to walk through a wall, I will eventually do so, but it will take something like 10^10^500 (I made this number up, the point is it's very large) tries. This is, in essence, a naive application of the tunneling effect I described above applied to macroscopic systems. The idea is that since I am composed of a ton of elementary particles, each of them would have to tunnel independently through the barrier, which is why the probability is so fantastically small, it is basically zero. However, even an explanation like this is a little troublesome because of decoherence, basically the complication that macroscopic objects are not described by QM, but rather by classical mechanics. Some others can speak more about this, but it's worth noting.
  6. Apr 9, 2012 #5
    This thread is misplaced. The humor thread is in the General subforum.
    Last edited: Apr 9, 2012
  7. Apr 9, 2012 #6
    Quantum tunneling is not relevant to large objects, I'll explain why at the end.

    Essentially, quantum tunneling is when a particle is able to traverse a barrier because of particle-wave duality. By 'barrier', I refer to anything from the barrier preventing a field in a false vacuum from reaching a true vacuum, to an actual, physical, barrier.

    Since a particle will take several paths compromising it the wavefunction it travels through spacetime, some will manage to traverse the barrier. Since wavefunctions make a completely random decision based off of probabilities where to collapse, it may collapse to the egienstate of the particle that was, say, on the other side of a wall.

    For this to occur to large objects, it would need to happen simultaneously to every single particle compromising the macroscopic object. The probability of this happening is so low, so close to zero, that you could probably take up all of physics forums severs trying to write it out.

    In short, the guy was full of it.
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