A Brief History of Time

A Brief History of Time

by

Stephen Hawking

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Entropy Term Analysis

The second law of thermodynamics states that disorder, or entropy, tends to increase in any isolated system. For example, a box with a divide in the middle could have oxygen on one side and nitrogen on the other. It is in an ordered state. If the divide is removed, however, the particles will tend to mix and occupy both sides of the box, a disordered state with higher entropy. This is not a definite outcome, but according to the laws of thermodynamics is overwhelmingly likely.

Entropy Quotes in A Brief History of Time

The A Brief History of Time quotes below are all either spoken by Entropy or refer to Entropy. 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 9 Quotes

The progress of the human race in understanding the universe has established a small corner of order in an increasingly disordered universe.

Page Number: 156
Explanation and Analysis:
Quotes explanation long mobile
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Entropy Term Timeline in A Brief History of Time

The timeline below shows where the term Entropy appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 7
Human Curiosity and Ingenuity Theme Icon
...black hole’s area could be determined by its event horizon. This non-decreasing idea sounded like entropy, or disorder, which the second law of thermodynamics states never decreases. For example, gas molecules... (full context)
Human Curiosity and Ingenuity Theme Icon
Jacob Bekenstein suggested a black hole’s entropy could be measured by its event horizon. As matter fell into the black hole the... (full context)
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
This maintained the law of entropy, but suggested that black holes ought to have a temperature, meaning it must emit radiation—but... (full context)
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...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 known to have a... (full context)
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...a black hole will reduce its mass. Its event horizon would contract, reducing its internal entropy proportionally to the increase in entropy outside. As the black hole contracts it heats up,... (full context)
Chapter 9
Human Curiosity and Ingenuity Theme Icon
...not see it jump back up and re-form. This is because of the law of entropy, which states that disorder in any system will usually increase as time goes on. A... (full context)
Human Curiosity and Ingenuity Theme Icon
Entropy, a concept defined in the second law of thermodynamics, directs the first, thermodynamic, arrow of... (full context)
Human Curiosity and Ingenuity Theme Icon
The thermodynamic arrow relies on the law of entropy, which states disorder becomes more likely as time goes on. Imagine a jigsaw box in... (full context)
Human Curiosity and Ingenuity Theme Icon
...more overall disorder. This means humans, and computers, only remember things in the direction of entropy, making the psychological arrow of time almost trivial, as it is determined by the thermodynamic... (full context)