Can Curving a Space-Cone Create a Black Hole?

  • Context: High School 
  • Thread starter Thread starter swampwiz
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the theoretical possibility of curving a space-cone to create a black hole, referencing concepts from general relativity and closed timelike curves (CTCs). Participants explore the implications of energy density and the feasibility of such constructs within the framework of spacetime.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that curving a space-cone requires a density of energy that must always create a black hole, referencing a video by Sean Carroll.
  • Another participant requests a link to the video and specific references to understand the terminology used and the concepts discussed.
  • A subsequent post attempts to provide the location in the video where Carroll discusses the topic.
  • Another participant expresses difficulty with the length of the video and asks for a specific timestamp to locate the relevant discussion.
  • A later reply indicates that Carroll discusses spacetimes containing closed timelike curves, but questions the feasibility of creating such spacetimes from our current understanding, suggesting that they may be inherent features rather than constructs we can achieve.
  • This participant also posits that it may be impossible to transition from a spacetime resembling our universe to one that includes a CTC.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the feasibility of creating black holes through curving space-cones or the existence of closed timelike curves, indicating multiple competing views and unresolved questions.

Contextual Notes

The discussion includes limitations related to the understanding of energy density, the definitions of closed timelike curves, and the theoretical constructs of spacetime, which remain unresolved.

swampwiz
Messages
567
Reaction score
83
require so much energy that the density of the energy - i.e., its mass equivalent - must always create a black hole? I was watching a video by Sean Carroll describe how this is *theoretically* possible, but obviously catastrophic.
 
Physics news on Phys.org
Please provide a link to the video and a timestamp for where Carroll talks about this. Better yet, a paper or textbook reference. Without a reference it's difficult to tell if you are describing something I understand but using unusual terminology, or describing something I can't help with.
 
  • Like
Likes   Reactions: Dale
Here is where he discusses it:

 
That's an hour long video. If you meant it to start somewhere in the middle, it didn't work. Can you give me a time stamp?
 
Try 38:05.
 
Carroll seems to be talking about spacetimes containing closed timelike curves. I don't think we know a way to create them, even in principle. They are pre-existing features of some spacetimes.

As far as I'm aware, it's a case of "can't get there from here". We can describe spacetimes containing CTCs. We can describe our spacetime. We don't know a way to describe something that starts looking like our universe but later on has a CTC in it. It may well be impossible to do so.
 

Similar threads

  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 29 ·
Replies
29
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 67 ·
3
Replies
67
Views
6K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 73 ·
3
Replies
73
Views
4K