Witness Life of Universe from Black Hole Event Horizon

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Discussion Overview

The discussion centers on the theoretical implications of a person (B) falling into a supermassive black hole and the possibility of witnessing the progression of events in the universe from various positions relative to the event horizon. The scope includes conceptual exploration of black hole physics and the effects of extreme gravitational fields on time perception and observation.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Participant 1 posits that if B turns on rocket boosters before reaching the singularity and expends infinite energy, B might be able to witness the progression of the universe.
  • Participant 2 counters that it is impossible for B to hold position or slow down after crossing the event horizon and asserts that hovering at the event horizon is also not possible.
  • Participant 3 clarifies that while hovering at the event horizon is impossible, it is feasible to hover just outside the horizon and suggests that one could see much of the future of the universe from that position, albeit with the risk of being affected by blue-shifted radiation.
  • Participant 4 adds that severe acceleration would also pose a danger, implying that the conditions near the event horizon are extremely hazardous.

Areas of Agreement / Disagreement

Participants generally disagree on the feasibility of B witnessing the universe's progression from the event horizon or after crossing it, with some asserting that hovering is impossible while others explore the implications of hovering just outside the horizon.

Contextual Notes

Participants express assumptions about energy expenditure and the nature of gravitational effects near black holes, but these assumptions remain unresolved within the discussion.

Ping
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I know there are many threads about falling into black holes and I'm sorry for posting another one. I have a specific question and couldn't find the answer in prior threads, although it's possible that it's there somewhere. If A is outside the supermassive black hole and B falls into it, I know that A will never see B cross the event horizon. The image of B will get dimmer and dimmer from A's perspective as A's coordinate time ticks off to infinite. I know that the proper time for B to reach the singularity is finite. I know that if B is looking back at A, B will only see a finite number of photons from A, and B will not witness the progression of the entire life of the rest of the universe.
Now imagine that B is falling in a spaceship with his rocket boosters pointed towards the black hole.​
B can look out the front window of his ship at A. If B turns on his rocket boosters just before passing into the singularity or being ripped apart by tidal forces, and B expends an infinite amount of energy, then can B hold himself in position or slow himself and witness the entirety of the progression of events in the rest of the universe? If this is impossible after crossing the event horizon, then can B hold himself at the event horizon using this energy and witness the same thing?
I apologize if I've assumed anything wrongly. I realize its impossible for B to have an infinite energy​
source on his ship.
 
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Ping said:
If B turns on his rocket boosters just before passing into the singularity or being ripped apart by tidal forces, and B expends an infinite amount of energy, then can B hold himself in position or slow himself and witness the entirety of the progression of events in the rest of the universe?

No.

Ping said:
If this is impossible after crossing the event horizon, then can B hold himself at the event horizon using this energy and witness the same thing?

No. It is not possible to "hover" at or inside the horizon, only outside it.
 
Although hovering at the event horizon is impossible, hovering just outside the horizon is allowed. If one were to hover close enough, one could see as much of the future of the rest of the universe as one pleased. (And get cooked by the blue-shifted radiation).
 
jbriggs444 said:
(And get cooked by the blue-shifted radiation).

If you weren't crushed by the severe acceleration. :eek:
 
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