# Cosmic censorship hypothesis

### 1969

The weak cosmic censorship hypothesis was conceived by Roger Penrose in 1969 and posits that no naked singularities exist in the universe. ==Basics== Since the physical behavior of singularities is unknown, if singularities can be observed from the rest of spacetime, causality may break down, and physics may lose its predictive power.

Cosmic censorship is not merely a problem of formal interest; some form of it is assumed whenever black hole event horizons are mentioned. The hypothesis was first formulated by Roger Penrose in 1969, and it is not stated in a completely formal way.

### 1985

Roberts in 1985: ds^2=-(1+2\sigma)\,dv^2+2\,dv\,dr+r(r-2\sigma v)\left(d\theta^2 + \sin^2 \theta \,d\phi^2\right),\quad \varphi = \frac{1}{2} \ln\left(1 - \frac{2\sigma v}{r}\right), where \sigma is a constant. ==See also== Black hole information paradox Chronology protection conjecture Firewall (physics) Thorne–Hawking–Preskill bet ==References== ==Further reading== ==External links== The old bet (conceded in 1997) The new bet Black holes General relativity

### 1991

These special circumstances need to be excluded by some hypotheses. In 1991, John Preskill and Kip Thorne bet against Stephen Hawking that the hypothesis was false.

### 1997

Hawking conceded the bet in 1997, due to the discovery of the special situations just mentioned, which he characterized as "technicalities".

Roberts in 1985: ds^2=-(1+2\sigma)\,dv^2+2\,dv\,dr+r(r-2\sigma v)\left(d\theta^2 + \sin^2 \theta \,d\phi^2\right),\quad \varphi = \frac{1}{2} \ln\left(1 - \frac{2\sigma v}{r}\right), where \sigma is a constant. ==See also== Black hole information paradox Chronology protection conjecture Firewall (physics) Thorne–Hawking–Preskill bet ==References== ==Further reading== ==External links== The old bet (conceded in 1997) The new bet Black holes General relativity

### 2018

The revised bet is still open (although Hawking died in 2018), the prize being "clothing to cover the winner's nakedness". == Counter-example == An exact solution to the scalar-Einstein equations R_{ab}=2\phi_a\phi_b which forms a counterexample to many formulations of the cosmic censorship hypothesis was found by Mark D.

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