Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

145 submissions , 122 unreviewed
3,930 questions , 1,398 unanswered
4,873 answers , 20,701 comments
1,470 users with positive rep
502 active unimported users
More ...

Violating Cosmic Censorship

+ 4 like - 0 dislike
50 views

Let's say we try to remove the event horizon of a Kerr black hole by throwing in matter with some large angular momentum. If it starts with GM > a, could we increase a at all? Would such a particle be able to enter the black hole?

This post imported from StackExchange Physics at 2014-05-04 11:16 (UCT), posted by SE-user user44056
asked May 2, 2014 in Theoretical Physics by user44056 (20 points) [ no revision ]
There's no known process by which this can happen using non-exotic matter without having the additional angular momentum end up being shed off in the form of gravitational radiation.

This post imported from StackExchange Physics at 2014-05-04 11:16 (UCT), posted by SE-user Jerry Schirmer

1 Answer

+ 5 like - 0 dislike

To expand on Jerry's comment a bit, there is a review article that describes the underlying physics here (caution PDF). The article is based on R. M. Wald's paper Gedanken experiments to destroy a black hole, Ann. Physics 82 548-556, though the paper is behind a paywall so that's not much use unless your college has access. The article actually describes a Kerr-Newman black hole, where the infalling particle can be charged and the attempt to create a naked singularity is to both increase the angular momentum and the charge.

As I'm sure you'd have guessed, the calculation is involved, but basically Wald concludes that you can't add enough charge because the field of the Kerr-Newman black hole ends up repelling your charged particle. You can't add enough angular momentum because the extra angular momentum stops the particle falling through the horizon.

This post imported from StackExchange Physics at 2014-05-04 11:16 (UCT), posted by SE-user John Rennie
answered May 2, 2014 by John Rennie (470 points) [ no revision ]

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
$\varnothing\hbar$ysicsOverflow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
To avoid this verification in future, please log in or register.




user contributions licensed under cc by-sa 3.0 with attribution required

Your rights
...