Mysteries of Modern Physics -- Time

Mysteries of Modern Physics -- Time is a set of 24 half-hour lectures, available on DVD or audio from The Great Courses.

See also my other course: Dark Matter, Dark Energy.

About the lectures

These are a series of twenty-four professionally produced pedagogical lectures on DVD or audio-only, discussing how scientists think about the mysteries of time. We will talk about what time really is, and how it works from the perspectives of philosophers, physicists, and neuroscientists. How do we measure and keep track of time? How does time relate to space? Why is there an arrow of time? How do we perceive the passage of time? How does the behavior of time relate to the origin of the universe?

The lectures are meant for anyone with a curious mind, regardless of their background. No prior familiarity with physics is assumed. We start with the basic questions of what time is and how we measure it, then move on to some of time's mysteries. The biggest mystery is the arrow of time: why is the past different from the future? That brings us to the ideas of entropy and the Second Law of Thermodynamics. We'll discuss the development of the Second Law, from a simple principle that was useful when designing steam engines to a bedrock rule of our understanding of the cosmos. Following the route laid down by nineteenth-century physicist Ludwig Boltzmann, we'll understand why the Second Law is true and how it relates to cosmology and the beginning of time. That will naturally lead us to a detour into complexity, life, memory, and psychology, before returning to the firm ground of physics to think about spacetime and black holes. The course concludes with some more speculative ideas about the multiverse and our place in the wider cosmos.


Here are the titles of each of the lectures, to give you an idea of what you will learn.

1. Why Time Is a Mystery
2. What Is Time?
3. Keeping Time
4. Time’s Arrow
5. The Second Law of Thermodynamics
6. Reversibility and the Laws of Physics
7. Time Reversal in Particle Physics
8. Time in Quantum Mechanics
9. Entropy and Counting
10. Playing with Entropy
11. The Past Hypothesis
12. Memory, Causality, and Action
13. Boltzmann Brains
14. Complexity and Life
15. The Perception of Time
16. Memory and Consciousness
17. Time and Relativity
18. Curved Spacetime and Black Holes
19. Time Travel
20. Black Hole Entropy
21. Evolution of the Universe
22. The Big Bang
23. The Multiverse
24. Approaches to the Arrow of Time

Teaser trailer

Continuing on

The lectures are loosely based on a book I wrote, From Eternity to Here: The Quest for the Ultimate Theory of Time. Many of the topics are also discussed in the book, sometimes in greater detail.

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