A Brief History of Time

A Brief History of Time

A black hole is a localized singularity that forms from a collapsing star. Once the star uses up its fuel, its spent energy is not enough to balance its own gravity, and it begins to collapse in on itself. When it is dense enough, its gravity is so strong that even light cannot escape its pull, and the boundary from which light cannot escape is called the singularity’s event horizon. Jacob Bekenstein suggested this event horizon is a measure of the black hole’s entropy, meaning that black holes ought to emit radiation because entropy should always be increasing, which also led to the realization they must shine, although we cannot see them. Black holes themselves cannot be directly observed, though scientists can observe their effects on surrounding material.

Black hole Quotes in A Brief History of Time

The A Brief History of Time quotes below are all either spoken by Black hole or refer to Black hole. For each quote, you can also see the other terms and themes related to it (each theme is indicated by its own dot and icon, like this one:
The Search for a Unifying Theory of the Universe Theme Icon
). Note: all page numbers and citation info for the quotes below refer to the Bantam edition of A Brief History of Time published in 1988.
Chapter 6 Quotes

The hostility of other scientists, particularly Eddington, his former teacher and the leading authority on the structure of stars, persuaded Chandrasekhar to abandon this line of work […] However, when he was awarded the Nobel Prize in 1983, it was […] for his early work on the limiting mass of cold stars.

Related Symbols: Nobel Prize
Page Number: 87
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Chapter 7 Quotes

[…] one evening in November that year, shortly after the birth of my daughter, Lucy, I started to think about black holes as I was getting into bed. My disability makes this rather a slow process, so I had plenty of time.

Related Characters: Stephen Hawking
Page Number: 103
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Black hole Term Timeline in A Brief History of Time

The timeline below shows where the term Black hole appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 3
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...Penrose showed that stars can collapse in on themselves to become singularities, in this case, black holes . While Penrose only talked about stars, a young Stephen Hawking saw the relevance this... (full context)
Chapter 4
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...forces are so weak compared to other forces. But gravity would be much stronger in black holes or at the big bang, and as such needs to be integrated into quantum mechanics.... (full context)
Chapter 5
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...them to collapse, and it is what happens in that time, when they become a black hole , that draws general relativity and quantum mechanics together. (full context)
Chapter 6
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John Wheeler came up with the name black hole in 1969 to describe an idea that had been around for around 200 years. In... (full context)
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John Michell’s paper in 1783 first suggested the idea of black holes , though he did not use the name. He said that any star that was... (full context)
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...helped to explain this, although it took decades for the relevance to be applied to black holes and massive stars. (full context)
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...losing the mass required to remain stable. If it doesn’t explode, it will become a black hole and ultimately collapse to infinite density. That shocked Eddington but, when Chandrasekhar won the Nobel... (full context)
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...than anything else, nothing else can escape either. This area of no return is a black hole , the boundary of which is called its event horizon. (full context)
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Because time is relative, what happens at a black hole will look different to different observers, such as someone on the surface of the star... (full context)
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...must be a singularity of infinite density and space-time curvature at the center of a black hole . This is similar to the beginning of time at the big bang, but is... (full context)
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...laws of science break down at singularities, and with them, the concept of time. A black hole’s event horizon could be considered a one-way membrane, allowing things in, but not out. Anything that falls... (full context)
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...of a star is much more rapid, and what the final stationary form of a black hole would look like was an open question. Werner Israel revolutionized views on black holes by... (full context)
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Isreal thought this meant only a perfectly spherical star could become a black hole , meaning there were no black holes in reality. But Penrose and Wheeler said a... (full context)
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Black holes were proposed before they were found. In 1962, Maarten Schmidt found what is now called... (full context)
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...that we cannot see seems impossible. But Michell suggested in 1783 we can measure a black hole ’s gravitational effects on the material around it. There are examples of systems where stars... (full context)
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More black holes have been found since, and given the age of the universe, there could be more... (full context)
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There could also be much smaller black holes , with a smaller amount of matter compressed by large external pressure, probably in the... (full context)
Chapter 7
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...focused on the big bang. Around the time of his daughter’s birth, he thought about black holes and their event horizon, a not very well-understood idea at the time, as he was... (full context)
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This non-decreasing nature of black holes determines much of their behavior. Penrose agreed with Hawking, and they determined a black hole’s... (full context)
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Jacob Bekenstein suggested a black hole ’s entropy could be measured by its event horizon. As matter fell into the black... (full context)
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This maintained the law of entropy, but suggested that black holes ought to have a temperature, meaning it must emit radiation—but black holes aren’t meant to... (full context)
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...in 1973, where he met Yakov Zeldovich and Alexander Starobinsky. They convinced Hawking that rotating black holes ought to emit particles based on the uncertainty principle. When Hawking later did the mathematics... (full context)
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...the spectrum of radiation emitted would be the same as any other hot body, and black holes seemed to obey entropy. Others have since confirmed the results, and black holes are now... (full context)
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In fact, the particles emitted do not come from the black hole itself, but the supposedly the empty space just outside the event horizon. This space is... (full context)
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Positive energy emerging from the black hole would be balanced by the negative energy falling in. According to Einstein’s E=mc2 equation, energy... (full context)
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Black holes a few times larger than the sun would be much colder than the general temperature... (full context)
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Black holes from the early universe would be much smaller though, formed by irregular pressure rather than... (full context)
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...can assess background gamma radiation in the universe to calculate how common these early universe black holes are. The evidence suggests they are scarce, so the likelihood of finding and harnessing one... (full context)
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If such a black hole were to blow up near Pluto, we could detect it, but the likelihood of that... (full context)
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The theory that black holes emit radiation rubbed people up the wrong way, and was the first significant example of... (full context)
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This new idea about black hole radiation suggests gravitational collapse is not so final after all. Mass or energy lost into... (full context)
Chapter 8
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...big crunch singularity when everything collapses back in on itself, or in localized singularities in black holes . But when applying quantum mechanics, it is clear that black holes re-emit mass and... (full context)
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...again. The central portions of the star contract into dense regions, becoming neutron stars or black holes , though this is not yet fully understood. Sometimes outer parts of a star can... (full context)
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...early universe would become more uniform like our own, and how there are not more black holes dating from that early period. (full context)
Chapter 9
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Hawking had to admit his mistake. When Eddington opposed black holes , he did so because he could not admit a mistake. Others often pretend they... (full context)
Chapter 10
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...what one can observe in the universe. For example, in the interior of a rotating black hole , or a space-time where two cosmic strings move past each other really fast. These... (full context)
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...going backward in time could be considered an anti-particle going forward in time. For example, black holes “emit” particles, where one component of a particle and anti-particle pair escapes as its partner... (full context)
Chapter 11
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...the uncertainty principle and general relativity. This has already resulted in significant rethinks, such as black holes not being black and the universe having no edges. The problem is that under the... (full context)
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...as we achieve higher energy production rates. There are upper limits of energy after which black holes form just from one particle. Though scientists cannot achieve these levels of energy anytime soon,... (full context)
Chapter 12
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...such a point in a big crunch. The theory also predicts other, localized singularities in black holes . The laws of science break down at these singularities, allowing room for God to... (full context)