My Brief History by Stephen Hawking

Author:Stephen Hawking [Hawking, Stephen]
Language: eng
Format: epub, mobi
ISBN: 978-0-345-53913-7
Publisher: Random House Publishing Group
Published: 2013-09-09T16:00:00+00:00

INTEREST IN gravitational collapse was reawakened in the early 1960s with the discovery of quasars, very distant objects that are very compact and powerful optical and radio sources. Matter falling into a black hole was the only plausible mechanism that could explain the production of so much energy in so small a region of space. Oppenheimer’s work was rediscovered and people began to work on the theory of black holes.

In 1967 Werner Israel produced an important result. He showed that unless the remnant from a non-rotating collapsing star was exactly spherical, the singularity it contained would be naked—that is, it would be visible to outside observers. This would have meant the breakdown of general relativity at the singularity of a collapsing star, destroying our ability to predict the future of the rest of the universe.

At first, most people, including Israel himself, thought this implied that because real stars aren’t exactly spherical, their collapse would give rise to naked singularities and a breakdown of predictability. However, a different interpretation was put forward by Roger Penrose and John Wheeler: that the remnant from the gravitational collapse of a non-rotating star would rapidly settle down to a spherical state. They suggested that there is cosmic censorship: nature is a prude and hides singularities in black holes, where they can’t be seen.

I used to have a bumper sticker that read BLACK HOLES ARE OUT OF SIGHT on the door of my office in DAMTP. This so irritated the head of the department that he engineered my election to the Lucasian Professorship, moved me to a better office on the strength of it, and personally tore the offending notice off the door of the old office.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.