Galileo and Einstein

Michael Fowler, UVa

PDF of Complete Set of Lecture Notes

Link to 2009 Homepage

Summary of the Course

The course explores two revolutions in our perception of the universe. The first, in which Galileo played the leading role, was the realization that what we see in the heavens—the moon, the planets, the sun and stars—are physical objects. For example, the moon has a rocky surface, not unlike some parts of earth, and is not made of some exotic ethereal substance, as had been generally believed before Galileo. This discovery led to the realization that the motions of the moon and planets obeyed the same physical laws as ordinary things moving on earth. Newton put this all together to give the first unified picture of the universe.

The second revolution was Einstein’s realization that this was not the whole truth—space and time are not as straightforward as they first appear, but are related to each other in a simple but unexpected way. Among other results, this leads to the surprising consequence that mass and energy are different aspects of the same thing!

The course will follow the development of ideas approximately in the historical sequence. It will begin by reviewing some of the Greek contributions to math and science, which were essential to both Galileo and Einstein in their work. We shall prove—and find very useful—Pythagoras’ theorem, and a few other ideas about triangles. We shall also look at Greek ideas about the solar system, and how they measured the distance to the moon quite accurately (using the ideas about triangles!).  We will examine how these ideas reached western Europe by way of the Arab world.

We shall do some of Galileo’s experiments which led to understanding motions of projectiles, and show how Newton connected these results with the motion of the Moon, and thereby all the planets. We shall then go on to consider the nature of light, for this is what led Einstein to question the concepts of space and time. The last part of the course will develop the theory of special relativity, including time dilation, relativistic mass increase, and E = mc2.

Overview and Lecture Index

Galileo’s Ideas in His Own Words (well, in translation)



Assorted Goodies

Check out my course on Modern Physics : it overlaps this course somewhat on Relativity, but then goes on to Quantum Theory. It is an introductory course for physics majors, but many of the lectures are at the same general level as this course.

The NASA Galileo Jupiter probe: this spacecraft has recently taken some fascinating closeups of Jupiter’s moons.

General Planetary Information.