Thought Experiment: Janet And The Black Box

Discussion in 'Physics & Math' started by davidelkins, Jul 20, 2016.

  1. davidelkins Registered Senior Member

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    108
    Thought Experiment: Janet And The Black Box

    A woman named Janet agrees to spend two years in a room that is filled with enough supplies to last her for the full two years. She agrees to not come out of the room for two years, but to remain inside the room for the entire duration of those two years. The room is treated as a black box.

    According to the rules no one within one light year of the black box as of the start of the two year period is allowed to communicate with her or know what is happening inside the black box for the full duration of the two years. Likewise, no one inside the black box is allowed to communicate with people who are within one light year of the black box as of the start of the two year period. Furthermore, no one inside the black box is allowed to know any events that are happening within one light year of the black box as of the start of the two year period. The only person inside the black box for those two years is Janet.

    Janet is given a telescope to study the night sky. Janet is asked to study events in the night sky that are happening one light year distance from the black box. Janet cannot relay the acquired information from the events happening one light year away until the end of the two year period because she is in a black box. The people who are within one light year of the black box as of the start of the two year period cannot relay their information to Janet until the end of the two year period because they cannot enter the black box.

    If Janet must wait two years to relay her acquired information to those who are within one light year of the black box as of the start of the two year period, then does it matter if the information is relayed to Janet faster than the speed of light? Can Janet acquire information about events happening one light year away faster than the speed of light if she remains in the black box for the full duration of the two year period?

    Author: David Elkins
     
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  3. Janus58 Valued Senior Member

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    No. Any artificial constraints you place on who Janet can or cannot communicate with will not have any effect on light speed limit on her ability to get information.
     
    Ultron likes this.
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  5. DaveC426913 Valued Senior Member

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    It certainly matters to Janet.


    I have a modification to your thought experiment for consideration:

    Imagine the black box inflates to 10,000 miles in diameter. Imagine that encompasses two people, or 200 people, or, say, 7 billion people.

    Nothing in your experiment has changed except the scale. We have now allowed every living creature in existence to examine the universe faster than light can get to us, simply by building a thin black wall around us.
     
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  7. davidelkins Registered Senior Member

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    What if even Janet does not get to see the information from the telescope until the two years are up. Then it wouldn't matter whether the information comes faster than the speed of light, as long as information from greater than one light year away is not received after the conclusion of the first of two years. DE
     
  8. DaveC426913 Valued Senior Member

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    Why do you think the laws of physics would take notice of what Janet is doing?
     
    Russ_Watters likes this.

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