# Douglas MacDougal

## Discovering the Universe ~

## Stories and Histories of Earth, Sky and Motion

Author of Newton's Gravity ~ An Introductory Guide to the Mechanics of the Universe (Springer, 2010)

## The orbital path of Mars relative to earth, 1600-1616, that I generated with mathematical software, after Kepler's similar drawing of the orbit from 1580 to 1596 using the data of Tycho Brahe,"on the assumption that the earth stands still, as Ptolemy and Brahe would have it." The original picture and quote are from Kepler's 1609 Astronomia Nova, translated by William H. Donahue, p.79 (Santa Fe: Green Lion Press, 2015)

My last project, Newton's Gravity, was published by Springer. Find out more about it on the NEWTON'S GRAVITY page here.

For a description of Springer's Undergraduate Lecture Notes in Physics series, click the link above.

## My current project

In the year 1602, a young German who had wanted to be a minister believed he had stumbled upon the secret ordering of the planets in the solar system. His arrangement, published in a book with the strange title Mysterium Cosmographicum, was based on the pure Platonic solids, relying upon mystical notions that were two millennia old even in his time. In the same decade, the same scholar set about to determine the true orbit of the planet Mars. He had at hand the best observational data on the orbit of Mars that had ever been accumulated. Yet, early in the treatise reporting his findings, he confessed his need to come to terms with Aristotle’s Metaphysics, a work of the 4th millennium BC. Moreover, much of his work, laden with Aristotelian references, was a detailed study and correction of the work of the mathematician Ptolemy of Alexandria, who whose Almagest dates to about 150 AD. Why did this man Kepler, celebrated as one of history’s first true ‘modern’ scientists, want to be known as the ‘heir to Aristotle’? What, in truth, was Aristotle’s hold on him? And why even did his predecessor, the revolutionary Copernicus, chide ancient Ptolemy for being insufficiently faithful to Aristotle? Did these and other scientists have to come to terms with the axioms of ancient Greek thought before the scientific revolution could get underway? Answering these questions for a broad readership has inspired my current exciting and fruitful delve into an earlier period in the history of astronomy than was treated in my Newton's Gravity.