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Suppose I am an observer inside the event horizon of a black hole, and I am part of a system comprising myself, an object and a singularity. Now I throw the object towards the singularity; what happens to the entropy of this system from my perspective?

Has the number of possible microstates reduced, violating the 2nd law of thermodynamics?

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  • $\begingroup$ Related: physics.stackexchange.com/questions/210846/… $\endgroup$
    – exp ikx
    Apr 25, 2019 at 14:10
  • $\begingroup$ When you are in a non-charged, non-rotating black hole, the singularity is not a place in space where you could throw things, but a future moment of time, say, "noon" by your wristwatch. So before "noon", there is no singularity inside a black hole, but the space around you is shrinking in 2 out of 3 dimensions thus becoming an increasingly tight cylinder. At "noon", this cylinder becomes a line squashing you thin and then time and existence end. This infinitely long line that exists for a zero period of time exactly at your "noon" is the singularity. Thus your question is not well defined. $\endgroup$
    – safesphere
    Apr 25, 2019 at 16:58
  • $\begingroup$ @safesphere I don't understand your comment. My world lines end at the singularity, but I can still look towards and away from it, and I can delay the onset of "noon" by exchanging momentum with the object and causing it to reach the singularity before me, from my perspective. Perhaps I'm missing something. $\endgroup$
    – quant
    Apr 26, 2019 at 11:50
  • $\begingroup$ @quant Yes you are missing the point that the direction toward the singularity inside the horizon is a direction in time. There is no spatial direction to the singularity, so no, you cannot look at it. The singularity is not an object that sits there, but a moment of time that happens to you when you reach it in time, not in space. The distance along your worldline is measured in seconds. You can make it just a bit longer by stopping your movement in space (not toward the singularity) to avoid the time dilation of special relativity. Everything hits the singularity at the same coordinate time. $\endgroup$
    – safesphere
    Apr 26, 2019 at 15:12

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