Can a falling feather inside a rocket ship create a black hole?

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Discussion Overview

The discussion revolves around the hypothetical scenario of a feather falling inside a rocket ship that is partially within a Schwarzschild radius, and whether this could lead to the formation of a black hole. Participants explore the implications of mass addition and event horizons in this context, raising questions about observations and physical consequences.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes that dropping a straw inside a rocket ship, with part of the ship within the Schwarzschild radius, could lead to the formation of a black hole if the straw adds sufficient mass.
  • Another participant argues that if the Schwarzschild radius is defined, the mass must already be a black hole, suggesting a contradiction in the initial scenario.
  • A participant questions the implications of dropping the straw, asking about the fate of the ship's hull and the effects of tidal forces, as well as the behavior of an observer outside the radius.
  • There is a discussion about the nature of event horizons and whether they would form instantaneously or spread at the speed of light, raising questions about the dynamics of mass removal and black hole formation.
  • One participant suggests that for the feather to cause a black hole, the original mass must be inside the ship, noting that the event horizon would occupy less space than the original mass.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and implications of black hole formation, with no consensus reached on the mechanics of the scenario or the consequences of the feather's fall.

Contextual Notes

There are unresolved assumptions regarding the definitions of black holes and Schwarzschild radii, as well as the physical behavior of mass and event horizons in this hypothetical situation.

Ray Eston Smith Jr
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I'm in a rocket ship hovering at a non-black-hole Schwarzschild radius. The bottom half of my ship is inside the radius. I drop a straw. As the straw crosses the Schwarzschild radius, at mid-ship, it adds just enough mass within the radius to form a black hole. What would I see? Would the bottom half of my ship suddenly black out?
 
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If the Schwarzschild radius of the mass is inside the bounds of mass itself (i.e. it's not compact enough to be a black hole), you'd have to be doing something pretty magical to be hovering above it -- you'd be in it.

- Warren
 
I don't understand your response. The bottom half of my spaceship is part of the interior mass. The top half, with me and the feather, is part of the exterior mass. I drop the feather and it falls to the bottom half which is inside the radius. That additional interior mass is just enough to make the black hole form. So what happens next?
- Ray
 
The first sentence of your post is a contradiction due to you using the wrong definition of a black hole: if it has a Schwarzschild radius, then it already is a black hole. More on this in your other thread...
 
Too convenient. You would never see the 'straw' hit the event horizon. A time dilation thing.
 
Okay, you say the straw would "freeze" above the event horizon. But what about the bottom half of my spaceship? Would I have a breached hull? Would I be torn apart by tidal forces? All this because I dropped a straw? What about an observer on the other side of the radius? When I dropped the straw would his side of the sphere instantly become an event horizon (allowing me to use the straw in the hole to send a faster-than-light message) or would the event horizon formation spread from my side to his side at the speed of light? If he withdrew matter from the far side before the event horizon wrapped around it, would the event horizon then unwrap back around to me, telling me that it's not really a black hole after all? (These difficulties would not occur if the event horizon at a spatial radius of zero.)
 
If the feather were to fall on something and add just enough mass to that thing so that it collapses and forms a BH, then the EH of that BH would beb less than the original radious of the mass before the feather landed, wouldn't it?

So you couldn't have the feather fall onto the mass and make it collapse unless the original mass was inside your ship. If that were the case, then the mass that was occupying some amount of space inside your ship would now be replaced by a BH occupying less space inside your ship.
 

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