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Space-Time Cloak Could Hide Actual Events

Posted by samzenpus on from the out-of-sight-out-of-time dept.

An anonymous reader writes "My first thought was, a hypothetical space-time invisibility cloak? That must be what hypothetical crime-fighting Einstein wears when he wades into the fray! Sadly, the researchers who thought up this trick to 'hide events' say that the metamaterials we have on hand will only allow for a nanoscale demonstration at best."

13 of 129 comments (clear)

  1. Minkowski you bastard by Adambomb · · Score: 4, Insightful

    mwahaha! if i'm never a part of events intersecting the light cone i dont exist!

    oh shiii-

    --
    Ice Cream has no bones.
    1. Re:Minkowski you bastard by Pawnn · · Score: 5, Funny

      You're making never leaving the house sound wayyy too scientific!

  2. Re: post by JustOK · · Score: 4, Funny

    all fine until the spacetime moderators show up.

    --
    rewriting history since 2109
  3. Better article by ath1901 · · Score: 4, Informative

    I found another article about the article which makes more sense: http://physicsworld.com/cws/article/news/44320

    There is a chicken and car analogy that should appeal to the crowd here:

    An analogy, says McCall, is a chicken crossing a busy road. Once the chicken steps onto the road cars must stop to let it pass, but as soon as it leaves the other side the cars would accelerate to catch up with the traffic ahead. To an observer farther down the road, the stream of passing cars would display no evidence of having slowed down.

    So, there is no magical disappearing of time or events or 4D cloaking of spacetime. That's just bullshit from some journalist who doesn't understand what spacetime or 4D means... Not more than a recorded tv program is cloaking space time.

    1. Re:Better article by ath1901 · · Score: 4, Informative

      Ok, so here's my personal rant:
      Why are all the non-linear optics experiments ALWAYS misinterpreted as having something to do with spacetime or relativity?

      A optical black hole is NOT a black hole. It's a piece of glass. Radiation from such an optical black hole is NOT Hawking radiation . It just happens to have the same explanation.

      Just because light in a vacuum "happens" to travel at the fastest possible speed ("the speed of light" = c) doesn't mean that when light is slowed down, the maximum speed is somehow slowed down. Spacetime is completely unaffected by the bending/stretching/slowing down of light. You CAN travel faster than the speed of light in a piece of glass but you CAN NOT travel faster than the theoretical speed limit known as "the speed of light" / c.

      Light isn't special. It is just another particle (photons). It doesn't affect spacetime in any way except by the gravitational force which happens to be tiny since it is so light (pun not intended).

    2. Re:Better article by locofungus · · Score: 3, Insightful

      So, there is no magical disappearing of time or events or 4D cloaking of spacetime.

      It's slightly more subtle than that. IIUC, it's impossible to detect something happening in the cloaked region of space. So in the chicken crossing the road scenario, to an outside observer, it looks like the cars travel at a constant speed and the chicken "magically" teleports from one side of the road to the other.

      The idea that something is in one state or another without being able to detect intermediate states is not new to physics. If you attempt to "watch" the transition between two eigenstates you will always measure one state or the other. We can have a mathematical model of how the wave function evolves, we can do experiments that demonstrate that the wavefunction must have been in a state that our mathematical model describes as a superposition of eigenfunctions, but we can never measure that superposition.

      In QM terms, I suppose the chicken would be described as "tunneling across the road"

      (note that I have no reason to suppose there is any relationship between 4d cloaking and QM tunneling - it's merely an analogy that came to mind)

      Tim.

      --
      God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
    3. Re:Better article by XxtraLarGe · · Score: 3, Interesting

      However it is logically demonstrable that time does not exist. For time to exist, the present is the infestimally small sliver between the past and the future, so infinitesimally small as to logically be zero, the past of course no longer exists and the future is yet to exist, hence for time to exist the universe can not.

      Sounds oddly similar to Zeno's Dichotomy Paradox. Thanks to calculus, the issue has been solved.

      --
      Taking guns away from the 99% gives the 1% 100% of the power.
    4. Re:Better article by MadKeithV · · Score: 3, Funny

      Time is an illusion.
      Lunchtime doubly so.

  4. Re:Hiding things? Isn't that the point of invisibl by Anonymous Coward · · Score: 5, Funny

    I thought a safe cracker was one without tuna.

  5. And may I be the first to say by boogersniffer500 · · Score: 3, Insightful

    I'll believe it when I don't see it!

  6. Re:Ffs by delinear · · Score: 3, Interesting

    Even though it's a joke it's probably not far from the truth. A dry scientific explanation is never going to make front-page on the millions of blogs, while "INVISIBILITY CLOAK NOW MONTHS AWAY!" is a shoe-in (unfortunately). Of course, you also then get a subset of scientists overstating their case to garner exactly this response, which doesn't help matters at all.

  7. Re:Wasn't this an episode of Star Trek? by uglyduckling · · Score: 4, Funny

    Ahhh! So you spotted that massive plot hole in the Harry Potter films too ;).

  8. Re:Ffs by DJRumpy · · Score: 3, Insightful

    It's all relative. Actually it is sped up, but not in the way you think. They've found that if a gravity well is strong enough, it actually pulls spacetime around it. If you were to shine a beam of light while based on spacetime that is moving, you in essence create a beam of light that is moving faster than the speed of light, at least for an observer standing on spacetime that is not moving.