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Randomness in time reversal case

  1. Dec 26, 2014 #1
    I have dice whit starting temperature of 0 K in vacuum and its displaying number 1 ,after drop it displays number 6 (for example) .
    Now if we reverse time, will dice sitting still on surface return to original position (displaying number one ) or it will display different random number ?
    23.jpg
     
  2. jcsd
  3. Dec 26, 2014 #2

    Vanadium 50

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    Since we cannot reverse time, I don't see that this question has an answer. (We could of course film this and play the film backwards, but I don't think this is your question)
     
  4. Dec 26, 2014 #3
    If time would be reversed in your example, why wouldn't the dice return to the previous position? After all this is effectively a reverse process nothing new would occur in it.
     
  5. Dec 27, 2014 #4

    Drakkith

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    The way you stated your question makes it ambiguous. What does "reverse time" mean specifically in this case? Is it different than what we mean when we talk about time reversal symmetry?
     
  6. Dec 27, 2014 #5

    Nugatory

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    The problem with this answer is that, as Vanadium50 says above it and Drakkith says below it, no one has any idea what either you or the original poster mean when you talk about " reversing time". There are at least three plausible interpretations of what the original poster means, and the answer is different for each one of the three (which is a nice trick for what looks like a yes/no question with only two possible answers).

    So let's hold off on trying to answer the question until we know what is, OK?
     
  7. Dec 27, 2014 #6
  8. Dec 27, 2014 #7

    Nugatory

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    It's seldom wise to trust summaries of new scientific work that have been written for the general public, and this article is no exception. You would think from reading it that the researchers have found interesting violations of the second law of thermodynamics that challenge our understanding of the forward-only motion of time at the nanoscale. But if you look at the abstract of the actual scientific paper (the paper itself is behind a paywall :headbang:) you will see that they've done something very interesting but not as much fun for the university PR department to write about (emphasis mine):
    So there's no "reversing time" going on, and no better answer to your question than the one that Vanadium-50 gave you above.
     
  9. Dec 27, 2014 #8

    Nugatory

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    Closed, and I'm going to take advantage of this opportunity to remind everyone that PF rules require providing sources. Stuff like this is the reason why.
     
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