Astronomer Galileo had backed Nicholas Copernicus’s idea that the sun was at the center of the universe and that the planets, including the earth, all orbited it. This contradicted the Catholic Church’s traditional teaching that the earth was at the center of everything and everything orbited it, which did not go down well. In 1609, Galileo used the newly invented telescope and demonstrated that moons orbited Jupiter, thus proving the earth wasn’t at the center of everything. He also showed that all objects fall at the same speed, regardless of their weight. He rolled differently sized balls down a slope and measured their acceleration. It was the first time anyone had thought to actually test this. Sir Isaac Newton used Galileo’s measurements in his own work. Stephen Hawking said he feels connected to Galileo, as he was born 300 years to the day after the astronomer’s death.
Galileo Galilei Quotes in A Brief History of Time
The A Brief History of Time quotes below are all either spoken by Galileo Galilei or refer to Galileo Galilei. For each quote, you can also see the other characters and themes related to it (each theme is indicated by its own dot and icon, like this one:
).
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 2
Quotes
The Aristotelian tradition also held that one could work out all the laws that govern the universe by pure thought: it was not necessary to check by observation. So no one until Galileo bothered to see whether bodies of different weight did in fact fall at different speeds.
Related Characters:
Sir Isaac Newton, Galileo Galilei, Aristotle
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Chapter 8
Quotes
The Catholic Church had made a bad mistake with Galileo when it tried to lay down the law on a question of science, declaring that the sun went round the earth. Now, centuries later, it had decided to invite a number of experts to advise it on cosmology.
Related Characters:
Galileo Galilei, Nicolas Copernicus
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Galileo Galilei Character Timeline in A Brief History of Time
The timeline below shows where the character Galileo Galilei appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
Chapter 1
...the center of the planets, to be taken seriously. German astronomer Johannes Kepler and Italian Galileo Galilei backed his theory, even though it was not perfect based on the observable movements...
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The final blow came to the ancient model with the invention of the telescope. Galileo observed Jupiter and found it had several satellites, meaning not everything orbited the earth. Those...
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Chapter 2
What we understand today about forces and motion dates back to Galileo and Newton. Before them, people believed Aristotle, who said an object was naturally at rest...
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...we could understand the whole universe just by applying logic, so no experiments were required. Galileo was the first to bother to check out the theory about weights falling at different...
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Galileo found that each ball increased its speed at the same rate, regardless of its weight....
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Newton used Galileo's measurements as the foundation for his laws of motion. He deduced that the force (the...
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The main difference between Aristotle's approach and that of Galileo and Newton is the former's idea of the preferred state of rest, meaning an object...
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Chapter 8
...Catholic Church was seeking input from scientists, centuries after making a bad call on challenging Galileo’s assertion the earth orbited the sun. At the end of the meetings, the Pope met...
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