A Brief History of Time

A Brief History of Time

Werner Heisenberg proposed the uncertainty principle when he found it was impossible to accurately measure the position and velocity of a particle without that examination affecting the particle’s position or velocity. To see the position of a particle, you must shine a quantum of light on it, and the more accurately you want to measure it, the shorter the wavelength of the light needs to be. The shorter the wavelength, the higher the energy of the quantum, and as such the more it will knock the particle off its original course. This principle is central to modern understanding of the small-scale structures of the universe.

Uncertainty principle Quotes in A Brief History of Time

The A Brief History of Time quotes below are all either spoken by Uncertainty principle or refer to Uncertainty principle. 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 4 Quotes

The success of scientific theories […] led the French scientist the Marquis de Laplace […] to argue that the universe was completely deterministic. Laplace suggested that there should be a set of scientific laws that would allow us to predict everything that would happen in the universe.

Related Characters: Werner Heisenberg, Marquis de Laplace
Page Number: 55
Explanation and Analysis:
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Uncertainty principle Term Timeline in A Brief History of Time

The timeline below shows where the term Uncertainty principle appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 4
Human Curiosity and Ingenuity Theme Icon
Werner Heisenberg used this theory to create his uncertainty principle. To measure a particle’s position and velocity, one must shine light on it to... (full context)
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
Science and Religion Theme Icon
Heisenberg, Erwin Schrodinger, and Paul Dirac in the 1920s created quantum mechanics based on the uncertainty principle. This theory does not predict definite outcomes, but potential outcomes. It works on the... (full context)
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...although a wave, could act as a particle, being emitted only in certain quanta. Heisenberg’s uncertainty principle made particles seem more like waves, with their movement spread out according to probability.... (full context)
Chapter 7
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...Starobinsky. They convinced Hawking that rotating black holes ought to emit particles based on the uncertainty principle. When Hawking later did the mathematics to investigate it, he found even non rotating... (full context)
Human Curiosity and Ingenuity Theme Icon
...outside the event horizon. This space is not actually empty—there are certain minimum fluctuations and uncertainty. Pairs of particles and virtual particles will appear and collide, annihilating each other. One will... (full context)
Chapter 8
Human Curiosity and Ingenuity Theme Icon
Science and Religion Theme Icon
...have left a set of rules to determine the universe, within the limits of the uncertainty principle, but how did he decide these laws? We could say we cannot possibly hope... (full context)
Human Curiosity and Ingenuity Theme Icon
...small differences in the early universe that later created the galaxies, and so on. The uncertainty principle tells us there was a minimum level of fluctuations, and the no boundary theory... (full context)
Chapter 9
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...singularities and edges, meaning the world is finite, smooth and uniform, to the extent the uncertainty principle allows. After a period of inflationary expansion, regions would slow their expansion and begin... (full context)
Chapter 11
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
...his own refusal to accept quantum theory despite his own input into its creation. The uncertainty principle, on which quantum theory is based, is fundamental, and must be incorporated into any... (full context)
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
...with incorporating the gravity into GUTs is that it does not take into account the uncertainty principle that defines quantum mechanics. (full context)
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Human Curiosity and Ingenuity Theme Icon
Thus, the first step is to combine the uncertainty principle and general relativity. This has already resulted in significant rethinks, such as black holes... (full context)
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Human Curiosity and Ingenuity Theme Icon
...The theories themselves cannot predict these values, which is a serious drawback. When incorporating the uncertainty principle and general relativity one can either adjust the strength of gravity or the cosmological... (full context)
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
The Danger of Stubbornness  Theme Icon
Science and Religion Theme Icon
...argue the third in order to leave room for God. With our understanding of the uncertainty principle, we have removed the third option. Activity is random to a certain degree, but... (full context)
The Search for a Unifying Theory of the Universe Theme Icon
Human Curiosity and Ingenuity Theme Icon
...such a theory, scientists cannot predict exactly the events of the universe, due to the uncertainty principle and the fact the math is simply too hard. While scientists know in essence... (full context)
Chapter 12
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The Danger of Stubbornness  Theme Icon
Today, Laplace’s approach is defunct because of the uncertainty principle of quantum mechanics, which introduces a minimum level of randomness. Quantum theory gives particles... (full context)