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Testing Einstein's 'Spooky Action at a Distance'

Posted by samzenpus on from the this-worked-in-a-different-timeline dept.

smooth wombat writes "Travelling to a time in the past is, as far as we know, not possible. However, Einstein postulated a faster-than-light effect known as 'spooky action at a distance'. The problem is, how do you test for such an effect? That test may now be here. If all goes well, hopefully by September 15th, John Cramer will have experimented with a beam of laser light which has been split in two to test Einstein's idea. While he is only testing the quantum entanglement portion, changing one light beam and having the same change made in the other beam, his experiment might show that a change made in one beam shows up in the other beam before he actually makes the change."

7 of 375 comments (clear)

  1. Causality by GWLlosa · · Score: 4, Interesting

    Does this mean that once the effect shows up in the one light beam, before he does it in the other light beam, he is somehow locked in to his future actions? If not, what happens if he just turns off the device?

    1. Re:Causality by BakaHoushi · · Score: 4, Interesting

      To me that sounds like changing the past.

      As you said, event B requires event A. Event B precedes event A.

      Let's say event A occurs when I press a button, just for the sake of simplicity. So if this formula is correct, event B will happen BEFORE I press the button. This is hurting my brain a little, but I think this would imply that event B could not happen unless I was truly planning on pressing the button. I can't "fake" the universe out by pretending to hit it, witness B, and then stop. Because if I were to do that, B would never happen. And... uhhh...

      OW. See, as much as I support the fields of science and research into all things, I'm concerned about screwing with time. It makes my head hurt and the possible consequences scare me a little. Teleportation gives me similar worries.

    2. Re:Causality by Verteiron · · Score: 3, Interesting

      Larry Niven wrote a short-story (surprise!) about how the universe protects causality. A clever man discovers that every civilization that has ever undertaken the task of building a time machine has vanished before they can finish it. He puts forth the idea that if plans for a working time machine were leaked to their current enemies, they would try to build it and therefore disappear as well. Before the plan can be put into action, though, the clever man's own (presumably stable yellow) star inexplicably goes nova, thus preventing the time machine plans from being leaked and protecting the nature of causality.

      I sure hope Niven's wrong about that.

      --
      End of lesson. You may press the button.
  2. Re:Very neat and interesting! by Kagura · · Score: 5, Interesting

    Also see the Renninger negative-result experiment, in which it was postulated and proven that a particle need not be detected in order for a measurement to have occured.

  3. Re:Isn't all time travel impossible? by JaWiB · · Score: 5, Interesting

    Suppose an astronaut travels away from the earth at 99.9% of the speed of light. According to relativity, if he ever returns then everyone on earth will have aged considerably more than he has. But he has to turn around at some point in order for this to happen, hence he has to accelerate. And it doesn't take any reference points to judge that acceleration, so you can in effect say that he has travelled into (Earth's) future, and that the entire Earth has not travelled into the past.

  4. Re:Things they need to consider.... by Anonymous Coward · · Score: 3, Interesting

    You are quite obviously talking out your ass.

    When sending any signal, they need to consider that the signal grows weaker the further it travels. This is obvious with 3-dimensional travel but when adding that 4th dimension, it degragates exponentially.

    Signal degradation is already exponential, and already takes into account time, "the fourth dimension." It is not possible for a signal to degrade without it being away from the source of its transmission, which necessitates its having propagated away, which requires it to exist later in time.

    They also need to consider the displacement that occurs as well. Obviously, the Earth is not in the same exact place a few seconds ago as it is now.

    Relative to what? Do you really not grasp why the Theory of Relativity is called the "Theory of Relativity"? Or for that matter, do you not understand the implications of the Copernican Revolution? Yes, the Earth is moving relative to the Sun, but that's just a matter of taking the Sun's perspective in order to simplify the math. In reality, there is no absolute perspective from which to say the Earth is moving relative to it. The only reason to say the Earth moves around the Sun instead of the other way around is the mathematical convenience. From the Milky Way's perspective, we're orbiting the core. From the Andromeda Galaxy's perspective, we're charging toward them. There is no preferred perspective.

    Yes, it's fun to just speculate on Slashdot, but you are far, far too ignorant of science to make even speculate pronouncements on the future of physics.

  5. Re:Quit it by kalirion · · Score: 4, Interesting

    Personally, I still believe that the outcomes of all the dice throws are predetermined. We just don't know how.