With scientists perhaps on the verge of unlocking the deepest secrets of the universe and with breaking news of discovery after discovery at the frontiers of research, understanding physics has never been so important. This course puts the awe-inspiring - and at times mind-bending - concepts behind relativity and quantum mechanics within reach of anyone who wants to understand them.
What are the two big ideas of modern physics? How can nonscientists gain a handle on these ideas and the radical changes they bring to our philosophical thinking about the physical world?
Understanding motion is the key to understanding space and time. Is there a "natural" state of motion? Learn why the ancients gave different answers to this question, and how Copernicus, Kepler, and Galileo laid the foundation for a new approach.
Isaac Newton was born in 1642, the year that Galileo died. You'll learn how he built on the work of Galileo and Kepler, developing the three laws of motion and the concept of universal gravitation. You'll learn why Newton's laws suggest a universe that runs like a clock.
The study of motion is not all there is to physics. By the 18th century, scientists were delving into the relationship between the two phenomena. Today, electromagnetism is known to be responsible for the chemical interactions of atoms and molecules and all of modern electronic technology.
In mechanics (the branch of physics that studies motion), the principle of Galilean relativity holds - meaning that the laws of mechanics are the same for anything in uniform motion. Is the same true for the laws of electromagnetism?
In the 1880s, Albert Michelson and Edward Morley conducted an experiment to determine the motion of Earth relative to the ether. You'll learn about their experiment, its shocking result, and the resulting theoretical crisis.
In 1905 a young Swiss patent clerk named Albert Einstein resolved the crisis that flowed from the Michelson-Morley result. When Einstein discarded the ether concept and asserted that the principle of relativity holds for all of physics, mechanics as well as electromagnetism, he was making a simple claim with almost unimaginably profound implications.
Why does the simple statement of relativity - that the laws of physics are the same for all observers in uniform motion - lead directly to absurd-seeming situations that violate our commonsense notions of space and time?
As a dramatic example of what relativity implies, you will consider a thought experiment involving a pair of twins, one of whom goes on a journey to the stars and returns to Earth younger than her sister!
10. Escaping Contradiction - Simultaneity Is Relative