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History of Science Galileo

History of Science Online

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LibraryThing: Galileo Week 13: Galileo

Galileo's Works

# Due Date Pts Activity Time
2 Wednesday
11:59 p.m.

Topic 1 + Quiz
Background: Without a sense of context, history is anachronistic.
Primary sources: Without documentary evidence, history is speculation
The first of two topic assignments per week involving both background and primary sources.

90 min.

“Philosophy [i.e., physics] is written in this grand book—I mean the universe—which stands continually open to our gaze, but it cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering around in a dark labyrinth.”
Galileo Galilei, Il Saggiatore (The Asssayer, 1616)

1. Watch the “From the vault: Galileo’s Works” video prompt for this assignment at Janux (script below). Some scientists, including Galileo, Newton and Einstein, have become mythological figures in our culture. This means that to understand them in historical context may take some extra effort. Think about the contrast between the historical Galileo and the mythological Galileo. So who was Galileo? What was he really like? What question do you have about Galileo that you would most like to have found an answer for by the end of this week?

2. Share your thoughts in the Discussion at Janux.

3. Watch a video entitled “The Life and Works of Galileo: A Guided Tour." This is an hour-long overview of Galileo's life and works I've presented in a number of places. While you watch, read the "Timeline and Readers Guide" (pdf). Hint: You may want to print out the pdf and follow along in it as you watch the video. This is a two-day assignment: today, as part of Topic 1, watch the video from the beginning through 37:30, where the title slide for the next section “Scripture and Copernicanism” will appear. Read the pdf until you get to the section also entitled “Scripture and Copernicanism.” At that point, stop for today; you’ll finish both the video and the pdf in the Topic 2 assignment for this week.

4. Quiz: Afterwards, take a Topic 1 quiz in the assignments area of Janux. The quiz will be composed of 12 of the true/false questions listed in the Study Guide. Topic 1 quizzes must be completed before Wednesday night at 11:59 p.m.

Optional: Some additional print sources are recommended at LibraryThing.

For additional images, see the History of Science Collections Flickr collection for Galileo.

Galileo is a wonderful writer, and I have sprinkled many quotations from his works throughout these exhibits and in the timeline. I hope you find them enjoyable. If you would like to read him for yourself, you will find that the timeline handout contains citations to recommended English translations of all his works. The timeline and the exhibits are derived from invited talks I have presented to astronomers and physicists at Fermilab, Florida State University, New Mexico State University, Michigan State University, and other places. The video version was recorded at a presentation to NASA engineers at Langley, VA, in July 2008.

The scholarship on Galileo is prodigious, and takes years to encompass. So where might you turn next? If I were to recommend just one book about Galileo, it would be Dava Sobel, Galileo's Daughter (Penguin, 2000). So if the assigned readings stir up your interest in Galileo, try Sobel's book. Put it on your Amazon wishlist. (Other recommended sources are listed in the More Info section at Exhibits Online.) Sobel's book was also the basis for a special 2-hour edition of NOVA that aired in October, 2002, but still can be found in late-night reruns: Galileo's Battle for the Heavens. If you get a chance to watch it, I highly recommend it. By the way, every image from a book that appears in that film is from the OU History of Science Collections; many are the same images that appear in the exhibits you will read this week. As you will discover, the OU Galileo collection is world-famous.

Script of the Janux "From the Vault" video:

Thanks for joining me in the History of Science Collections of the University of Oklahoma Libraries. Let’s look at some of the treasures in the OU Galileo collection.

Galileo's first printed book was a manual on the operation of a geometrical and military compass. The instrument contained scales of his own innovative design, useful for an astonishing variety of calculations in the field. The Oklahoma copy of Galileo's first printed work contains his own marginal notes, including corrections which were quickly incorporated into subsequent copies of the first printed edition. Because it was the first copy off the printing press, see how the fresh type bit deeply into the paper? OU holds Galileo’s own copy of the first and rarest of Galileo’s books.

Galileo’s second printed book was a “Defense against the calumnies and impostures of Baldesar Capra,” who had plagiarized Galileo’s first book and published instructions for making Galileo’s Compass. The OU copy of Galileo’s second printed book contains Galileo’s handwriting. It is inscribed by Galileo to a friend who was a physician in Venice.

In his 3rd printed book, The Starry Messenger, Galileo published the first observations of the heavens made with the telescope. The Sidereus nuncius catapulted Galileo into international celebrity status almost overnight. In this work Galileo demonstrated that the Moon has mountains. Galileo also discovered four satellites revolving around Jupiter, printing more than 60 observations of their positions from night to night. What we call the Galilean Moons, Galileo called the Medicean stars. Jupiter stood for the Grand Duke of Tuscany, and the four satellites stood for the Grand Duke's four sons. That is how you would write a grant application in the 17th century! But the book was printed in such haste that Galileo came up with this idea only after the first pages were already printed, so you can see that he pasted the new name on top of this previously printed page. The book’s title, Sidereus nuncius, means Ambassador from the Stars, and refers to Galileo himself. The four satellites of Jupiter were a message from the heavens delivered by none other than Galileo for the honor of Cosimo Medici, the new Grand Duke of Tuscany. Within months Galileo joined Cosimo’s court in Florence.

In this book on floating bodies, Galileo demonstrated the ignorance of physicists regarding why objects float in water.

Galileo next published a description of sunspots. At the top of the title page, we see Galileo’s geometrical compass and telescope. By tracking the motion of sunspots across the face of the Sun, Galileo proved that they were on the Sun's surface, not little planets orbiting nearby.

In response to gathering criticism, Galileo wrote a short reconciliation of Scripture and Copernicanism which circulated in manuscript as the “Letter to the Grand Duchess Christina." Galileo argued that the purpose of Scripture is to tell us how to go to heaven, not how the heavens go; Scripture never errs, but its interpreters do err; and read rightly, Scripture and Science will never conflict (there is a unity of truth). That which is obscure (figurative language) should be explained by that which is clear (mathematical demonstrations). To show the traditional basis of his approach, he cited St. Augustine throughout.

In 1623, Galileo’s supporter and friend, Cardinal Maffeo Barberini, became Pope Urban VIII. The election of Barberini seemed to assure Galileo of support at the highest level in the Church. At the top of the title page is the crest of the Barbarini family, showing three busy bees. Galileo dedicated this book to the new pope, and argued that mathematics is the language of nature.

This is the famous Dialogue on the Two Chief Systems of the World, published in 1632, the book for which Galileo was put on trial. If we look closely at the frontispiece, Aristotle and Ptolemy on the left hold an Earth-centered armillary sphere. On the right, Copernicus, dressed in Catholic garb, holds a Sun-centered model of the universe. Galileo was already famous across Europe and didn't have to write in Latin. He wrote this in Italian, and it was an immediate best-seller. The book is a literary masterpiece, cast in the form of a Platonic dialogue between three characters: Salviati, Sagredo and Simplicio. Galileo obtained official permission to publish this book from the Vatican and the censors in Florence. In a private conversation, the pope also gave him permission to publish it, so long as he kept the conclusions hypothetical. The annotation says that this figure of falling bodies is in error, it is upside down. This printer’s error is corrected in the second edition. This is Galileo's handwriting, in his own copy of the Dialogue. Here is a new sentence by Simplicio to go before a long paragraph by Salviati, again written in Galileo's own hand. It is almost as if we were in his study, looking over Galileo’s shoulder in the crucial months before his trial. Far from Rome, in Oklahoma today one may now hold the very copy Galileo held in his hands.

In addition to all of Galileo’s first editions, the OU Galileo collection includes subsequent editions and translations. This is the first English translation of any of Galileo’s works. It includes the Dialogue on the Two Chief Systems of the World and Galileo’s Letter to the Grand Duchess Christina. The volume is charred and blackened around the edges. Fewer than 50 copies survive, as most perished in the Great Fire of London in 1665.

Under house arrest, Galileo turned his attention to a number of topics that had long interested him. This is his masterwork of physics, the Discourse on Two new sciences. Galileo’s first new science is tensile strength. Did you know that Galileo’s works included a study of the tensile strength of bones? Galileo’s argued that the bones of giants would not have the same shape as ours. Galileo’s second new science is motion, including the parabolic motion of projectiles, and the law of falling bodies. Two new sciences was Galileo’s last book.

While many major libraries hold one or two first editions of Galileo, OU holds the entire set of 12 first editions.

Science is a story. What stories do you want to tell about Galileo?

TOPIC QUIZ: The statements are either True or False. When you take the quiz at Janux, you will see 12 of these statements, chosen at random, worth 2 points each.

From the Vault video: Galileo’s Works

  1. The OU copy of the 1st edition of Galileo’s first printed work, the Compasso, contains Galileo’s handwriting.
  2. The OU copy of the 1st edition of Galileo’s second printed work, the Difesa, contains Galileo’s handwriting.
  3. The OU copy of the 1st edition of Galileo’s third printed work, the Sidereus nuncius, contains Galileo’s handwriting.
  4. The OU copy of the 1st edition of Galileo’s Dialogo, contains Galileo’s handwriting.
  5. The OU copy of the 1st English translation of any of Galileo’s works is charred and blackened around the edges, saved from a fire.
  6. While many major libraries hold one or two first editions of Galileo, OU holds the entire set of 12 first editions, as well as many subsequent editions and translations.

Galileo’s Life and Works: A Guided Tour (auxiliary video and timeline pdf)

  1. Galileo thought that physics should be qualitative.
  2. Archimedes and Ptolemy represent non-mathematical varieties of Aristotelian physics.
  3. Galileo and his mistress had a daughter during the time Galileo taught mathematics at Padua, in the Republic of Venice.
  4. Galileo’s first published book was a manual for the operation of a calculating instrument he had invented.
  5. Galileo’s second published book was a defense of his compass in the face of attempted plagiarism.
  6. Galileo invented the telescope.
  7. Galileo used the telescope to begin mapping the Moon, including a large, prominent crater that he named after himself.
  8. Galileo argued that the Moon and Earth are similar in that both have mountains, oceans, an atmosphere, and shine by reflected light.
  9. Through Galileo’s telescope, bright stars appeared much larger than faint stars.
  10. Galileo’s telescopic discoveries showed that the absence of stellar parallax was no longer a valid objection to Copernicus.
  11. Galileo’s telescopic discoveries proved that multiple centers of revolution must exist in the solar system.
  12. Galileo’s telescopic discoveries proved that a moving Earth would not necessarily leave its satellite (the Moon) behind.
  13. Galileo named the four moons of Jupiter after himself, the so-called Galileian Moons.
  14. After publication of the Sidereus nuncius (1610), Galileo faced intense opposition from the mathematicians and astronomers in Rome.
  15. Mathematicians and astronomers in Rome refused to look through Galileo’s telescope.
  16. Galileo founded the Academy of the Lynx to provide support for his scientific investigations.
  17. Archimedes’ work on floating bodies was a favorite treatise of university physicists.
  18. Galileo argued that sunspots are little planets that revolve around the Sun at a closer distance than Mercury.
  19. In Rosa Ursina, Christoph Scheiner argued that sunspots are little planets that revolve around the Sun.


Do you have a great quote for this page? Let me know! (If used, a new quote is worth 1 point extra credit)

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HSCI 3013. History of Science to 17th centuryCreative Commons license
Kerry Magruder, Instructor, 2004
Brent Purkaple, TA

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Many thanks to the pedagogical model developed in Mythology and Folklore and other online courses by Laura Gibbs, which have been an inspiration for this course.

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