One would avoid these problems if what I call the chronology protection conjecture holds.

See also Chronology protection conjecture.

Stephen Hawking in his 1992 paper on the chronology protection conjecture posited that closed timelike curves cannot be created, and thus cannot be used for time travel.

Furthermore, Stephen Hawking has suggested a mechanism he describes as the chronology protection conjecture, which would destroy any such closed timelike curve before it could be used.

The chronology protection conjecture is a conjecture by the physicist Professor Stephen Hawking that the laws of physics are such as to prevent time travel on all but sub-microscopic scales.

The chronology protection conjecture should be distinguished from chronological censorship under which every closed timelike curve passes through an event horizon, which might prevent an observer from detecting the causal violation.

Dr. Thorne, in his book "Black Holes and Time Warps: Einstein's Outrageous Legacy" (Norton, 1994), says that Dr. Hawking offered to bet that something called "the chronology protection conjecture" is true.

Maybe Steven Hawking was right in his chronology protection conjecture - maybe the universe protects itself from alterations via time travel - removes unwelcome Thornes from its side - whether by misdirecting travellers, blowing up AWHs, both, more.

"The Chronology Protection Case" extrapolates from Stephen Hawking's chronology protection conjecture, and posits a vengeful universe that seeks to protect itself from time travel by killing any scientists who discover or even begin to understand how to do it.

Some physicists speculate that the CTCs which appear in certain GR solutions might be ruled out by a future theory of quantum gravity which would replace GR, an idea which Stephen Hawking has labeled the chronology protection conjecture.

Analyses using the semiclassical approach to incorporating quantum effects into general relativity have sometimes indicated that a feedback loop of virtual particles would circulate through the wormhole with ever-increasing intensity, destroying it before any information could be passed through it, in keeping with the chronology protection conjecture.

These semiclassical arguments led Hawking to formulate the chronology protection conjecture, suggesting that the fundamental laws of nature prevent time travel, but physicists cannot come to a definite judgment on the issue without a theory of quantum gravity to join quantum mechanics and general relativity into a completely unified theory.