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Can the future affect the past?

Discussion in 'Political Discussion' started by reflexblue, Jul 25, 2007.

  1. reflexblue

    reflexblue PatsFans.com Supporter PatsFans.com Supporter

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    #91 Jersey

    Love This Stuff.:rocker:
  2. Pujo

    Pujo Rookie

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  3. Holy Diver

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    Quantum mechanincs and quantum physics are so hard to grasp.....Its odd to me that scientists accept these as fact when they can't be proven. Its kindof just a way to say that crunching all possible outcomes...anything is possible.

    example:

    at some point in time...in a parallel universe....YOU are reading what I have typed in this very message. The words I've typed will eventually fly out of the screen and eat you.

    THAT is a theory of quantum physics.

    Its awesome!

    So, Pujo, it indeed does have to do with politics.....it has to do with EVERYTHING. Wanna get really confused? Read "The Holographic Universe"
    Last edited: Jul 25, 2007
  4. Pujo

    Pujo Rookie

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    Well, I wouldn't say that they can't (or haven't to an extent) been proven. The practical effects of quantum mechanics have been experimentally verified (at least the big 4 QM predictions: quantinization of matter & energy, the uncertainty principle, entanglement, and wave-particle duality). Now some of the weirder aspects of QM are starting to show up experimentally (see the future-affecting-the-past experiment in the link I posted). Many QFT's (quantum field theories, like QED and QCD - the theories of "forces") have also been shown to make extremely accurate predictions (QED has been called the most accurate theory in physics). What's not known (though I have a strong feeling it will be within our lifetimes) is whether the non-determinism (randomness) & non-locality ("action at a distance") of quantum theories are the "true reality", or whether it just seems that way to us because we aren't getting the whole picture. And of course the "next generation" of physics, string theory and beyond, is entirely in its theoretical stages, nothing has been experimentally proven (and won't be for a long, long time) though those aren't quantum theories per se.

    I think the "anything can happen" thing gets used too casually. While the Heisenberg uncertainty principle does (accurately) say that things that are clasically "impossible" might still happen because of QM, the probability of something macroscopic happening is so small that the chance of it actually happening in the lifetime of the universe is very, very close to zero. On the other hand, small objects (like electrons) take advantage of the HUP to tunnel through solid barriers regularly. Tunneling microscopes are based on it.

    That looks like an interesting book, thanks. I haven't read it, though I read a very good book partially on the subject by Leonard Susskind, who was also involved in formulating the holographic principle ("Cosmic Landscape: String Theory and the Illusion of Intelligent Design"). I don't quite understand the holographic principle myself (though I understand the reasoning behind it, having to do with the entropy of black holes), but it's very interesting and ties in with an idea I take great interest in called digital physics (the idea that the universe is a computer, whether intentionally built or not).
  5. Real World

    Real World Moderator Staff Member

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    Who's on first? :eek:
  6. STFarmy

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  7. Pujo

    Pujo Rookie

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    What's really freaky is that in a thread about the future affecting the past, reflexblue's reply somehow got placed above my original post.

    Don't toy with me, laws of physics!
    Last edited: Jul 26, 2007
  8. Holy Diver

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    QUANTUM MECHANICS at its finest right there!
  9. PatsFanInVa

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    Sure, we don't want those messy macroscopic effects ever occuring. Oh no, perish the thought. Worse yet we don't want them controllable...

    Unless of course it's 2005 and we're thinking of the trajectory of a certain football thrown by one Tom Brady and picked off by one Champ Bailey...

    Then, perhaps, we're willing to step into... the twilight zone.

    But what then? How many Rrrrraiders fans want that tuck game back? Time-meddlers will virtually erase Adam Vinatieri's career, given how many game-winners he's booted in the big ones...

    I remember the good old days when we just got an inkling of something unexplainable which then transpired, and called it a day, and I strongly suspected last night I'd feel this way this morning. It was a premonition of nostalgia for deja vu.

    I'd trot out my own understanding of the topic, just to demonstrate the true meaning of "microscopic," but that would just be beating a half-dead cat.

    But I will leave you all with my contribution to the macroscopic time-meddling: were it to become available, we could go back in time, grab TS Eliot's "The Holo Men," and "fix" the title of it to read by the stanard spelling, "Hollow," to preemptively squash the entire ridiculous realm of speculation that he had been affected by merry pranksters from the future.

    Oh, I see one of you guys took that one and ran with it.

    And so we prove once again that the best proof of a conspiracy is its unproveability, which just proves the conspirators are really good.

    QED,
    pun intended,
    PFnV
  10. QuiGon

    QuiGon Banned

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    Yes, it's entirely possible that the future can affect the past. What we first need to establish is that time is not observed the same for everyone and everything everywhere (Einstein taught us this). Imagine time is a highway, and all of us human beings are on a bus travelling down this highway... other cars and buses are going to pass us, or we're going to pass them.

    The mind blowing part comes from the realization that (if we are to believe quantum mechanics) there are also going to be buses travelling in the opposite direction.
  11. Pujo

    Pujo Rookie

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    This is different from special relativity. Special relativity allows time to slow down in a non-inertial frame of reference (which means either an accelerating frame, or a frame within a gravity field, since there's no distinction between the two per the Equivilence Principle). If an object with mass could accelerate to the speed of light, time could even stop, though SR doesn't allow an object with mass to get to the speed of light (though they can get close). SR would not allow time to go backwards without an object exceeding the speed of light, and while the equations of SR and GR don't rule it out (which lead to the now mostly-discredited predictions of tachyons), the fact that we don't observe causalty being violated is pretty strong evidence that it doesn't happen.

    In this experiment, nothing exceeds the speed of light (a photon, being massless, can only travel at exactly the speed of light). The reason this is possible in QM is that no information can be sent back in time since the result of the experiment isn't known until the final measurement, which happens after all other events have taken place. This is called the "no communication theorem". It's like the universe can do weird stuff like send information back in time, as long as nobody can get that information until after the point where it was sent back.
    Last edited: Jul 27, 2007
  12. QuiGon

    QuiGon Banned

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    Well, FWIW, I understand the rough basics of QM* but it is clear I don't really follow the subject or latest advances and discoveries from the world of quantum physics as much as you do. I more enjoy reading about the physics of wicked big things, instead of wicked small things. Once people start talking about photons and muons and superstings, I tend to tune out.

    *Someone once said (paraphrasing) "No one understands QM, except perhaps Einstein." So I shouldn't say I understand the rough basics of QM. What I should say is I think I sorta kinda understand the basic ideas that roughly approach the theories behind the beginning, most elementary and simplest notions of QM.
    Last edited: Jul 27, 2007
  13. Pujo

    Pujo Rookie

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    Cosmology is really interesting, too, though I admit particle physics has more of an allure for me.

    Who said that? Einstein never believed in QM (see the "EPR Paradox" and "local hidden variables"), remember his famous quote, "God doesn't play dice with the Universe" (to which Niels Bohr replied, "Einstein, don't tell God what to do.") Funny as it is, Einstein's only Nobel prize wasn't for his two theories of relativity (which weren't "proven" until after his death), but rather for his discovery of the law of the photoelectric effect - he actually coined the term quanta. He just didn't believe in QM's randomness (the HUP) or entanglement (action at a distance).

    However, all that notwithstanding, I'm with you: I sure as hell don't understand quantum mechanics, I only understand what some brilliant people have been able to put into simple language for the lay man.
    Last edited: Jul 27, 2007
  14. QuiGon

    QuiGon Banned

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    I can't remember who had the quote about Einstein. It's just something I remember reading once... I am sure I am botching the quote, but not intentionally. (EDIT: I will try and find the specific quote later this evening from home).
    Well I will be the first to admit that your lack of understanding QM is greater than my lack of understanding QM... no wait, that came out wrong... believe it or not, it is meant as a compliment :D
    Last edited: Jul 27, 2007
  15. PatsFanInVa

    PatsFanInVa PatsFans.com Supporter PatsFans.com Supporter

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    One of the beautiful and so appropriate aspects of QM is that people who don't understand it, seem to have no trouble benefitting from its application, tunneling electrons and all.

    I'm still comforted by the possibility that the theory appears to predict bizarre behavior in the universe, once it truly is understood, it will seem like nature once again. For the time being, what we're saying is not just that the layman doesn't understand it, but that the expert doesn't either -- which is way too much like magic. Of course, I never met a medieval conjurer with a tunneling electron microscope... so that puts a crimp in that whole reading.

    PFnV
  16. sdaniels7114

    sdaniels7114 Rookie

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    This is kinda like the Arod thing. He's sitting on HR#499 and since there's a suspended game to be played out in the next couple of days he might hit a HR today, putting him in the 500 club and then play in and hit a HR in the suspended game and somehow un-break and then re-break that barrier since suspended game stats are suspended until the game is actually played to the end. This of course doesn't change the fact that he's Arod and therefore $ucks, but its still sort of Quantum-y in a way.
  17. QuiGon

    QuiGon Banned

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    I couldn't find the quote, and will concede it is entirely possible I am either misremembering the quote or it was simply spoken about something else and not QM. One interesting quote I did find comes from Neils Bohr: "If you do not get dizzy sometimes when thinking about quantum mechanics, then you have not really understood it." (source: The Elegant Universe, Brian Greene).

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