Would Rapid Expansion of a Parallel Universe Affect a Black Hole?

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Discussion Overview

The discussion revolves around the hypothetical scenario of a black hole interacting with a rapidly expanding parallel universe. Participants explore the implications of such an interaction, questioning whether it would lead to the destruction of the black hole or warp the spacetime around it. The conversation touches on concepts of cosmic expansion and the nature of the universe.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes a scenario where a black hole encounters a rapidly expanding universe, questioning the effects on the black hole.
  • Another participant argues that the universe does not expand into anything, emphasizing that it is the fabric of the universe itself that expands.
  • A further elaboration clarifies that the current model of cosmic expansion describes the evolution of the universe from a dense state to a lower density state, and that black holes cannot interact with another universe in the context of this expansion.
  • Some participants express skepticism about the relevance of the question to the forum, suggesting it may belong in a science fiction context.
  • One participant reiterates the idea that if the universe expands like a balloon, it would create reactions against other entities, but this is challenged by others who clarify that the universe is all-encompassing and does not expand into anything.
  • There is a discussion about the nature of expansion, with participants explaining that distances between objects increase over time rather than the universe expanding into a physical space.

Areas of Agreement / Disagreement

Participants generally disagree on the nature of cosmic expansion and its implications for the hypothetical scenario. There is no consensus on whether the original question is valid within the framework of current cosmological understanding.

Contextual Notes

Participants express varying interpretations of cosmic expansion, with some relying on analogies that may not align with current scientific models. The discussion reflects a mix of speculative reasoning and attempts to clarify misconceptions about the nature of the universe.

Dryson
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I have a "What If." question.

Suppose a black hole located in a universe encounters a rapid expansion of another universe with the universe that is in close approximation to the black hole. Would the rapidly expanding universe destroy the black hole or would the expanding universe actually cause the space time around and within the black hole itself to be warped as the two colossal forms of energy unite?
 
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Expansion does not work that way. The universe is not expanding into something. It is the something of the Universe that expands.
 
To elaborate on Orodruin's post, our current model of expansion describes the evolution of our own universe from a very dense state to a much lower density state over the last 13.7 billion years due to expansion. Expansion here means 'unbound objects within the universe recede from each other over time'. It does not mean that the universe has a boundary that is moving outward into pre-existing space. By our current understanding, a black hole cannot encounter another expanding universe because that is not what expansion, in the cosmological sense, is talking about.
 
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Shouldn't this be in the scifi forum?
 
Chronos said:
Shouldn't this be in the scifi forum?
Yep.
 
Orodruin said:
It is the something of the Universe that expands.
If something is expanding does it not occupy a larger area of space? If it is the something of the Universe that expands like a balloon expands then the Universe would expand outwards as an expanding force that will create an equal and opposite reaction against other something's in the Universe.

The reason this question is based off of two black holes being theorized about colliding - http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q6.html
 
Dryson said:
If something is expanding does it not occupy a larger area of space? If it is the something of the Universe that expands like a balloon expands then the Universe would expand outwards as an expanding force that will create an equal and opposite reaction against other something's in the Universe.
No, that's not the way it works. The universe is all there is. It doesn't expand "into" or "against" anything. Drakkith already explained this.
 
Dryson said:
If it is the something of the Universe that expands like a balloon expands then the Universe would expand outwards as an expanding force that will create an equal and opposite reaction against other something's in the Universe.

You're thinking of space as something physical that presses up against something else as it expands. This is not correct. Expansion means that the distances between objects within space increases over time. The exact way expansion works is that the recession velocity, which is simply the speed that an object is moving away from us, increases as the distance between us and the object increases. If you double the distance, the recession velocity doubles as well. So if you choose an object at any finite distance from us, there will be a clear velocity that it is moving away at. Expansion will never cause an object to come towards us. In other words, there are no other 'somethings'. Expansion applies to our universe just as I explained.
 

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