Professor at California Institute of Technology

Professor at California Institute of Technology >

Why Time Is a Mystery
Episode 1 of Mysteries of Modern Physics: Time Series
Begin your study of the physics of time with these questions: What is a clock? What does it mean to say that "time passes"? What is the "arrow of time"? Then look at the concept of entropy and how it…
The Strangest Force
Episode 1 of Black Holes, Tides, and Curved Spacetime
Begin your exploration of gravity with Isaac Newton and the famous story of the apple. Why was it such a breakthrough to connect a falling apple with the faraway moon? Review the essential characteristics of gravity and learn why small…
Publius Cornelius Scipio
Episode 1 of Famous Romans
It is a March day in 218 B.C., the year that will see the beginning of the Second Punic War. Join the consul P. Cornelius Scipio and his son as they tour the Forum, discussing its statues of heroes from…
The Importance of the Higgs Boson
Episode 1 of The Higgs Boson and Beyond Course
Why was the discovery of the Higgs boson such a big deal? That's the key question that Professor Carroll tackles in his illuminating introduction. Take a fascinating dive into the world of modern particle physics and see how the Higgs…
What Is Time?
Episode 2 of Mysteries of Modern Physics: Time Series
Approach time from a philosophical perspective. "Presentism" holds that the past and future are not real; only the present moment is real. However, the laws of physics appear to support "eternalism"--the view that all of the moments in the history…
Quantum Field Theory
Episode 2 of The Higgs Boson and Beyond Course
Toss out the textbook image of electrons circling an atom's nucleus. This lecture explores the big twist of quantum field theory: The world isn't really made of particles. They're fascinating and necessary figments of quantum mechanics created by observing the…
Free Fall and Inertia
Episode 2 of Black Holes, Tides, and Curved Spacetime
Review three great discoveries by the "grandfather" of gravity research, Galileo Galilei. His most famous experiment may never have happened, but his principle of inertia, law of free fall, and principle of relativity are the basis for everything that comes…
Episode 2 of Famous Romans
Few Romans did as much to make Rome a world power as did its worst enemy, Hannibal. This lecture follows the great Carthaginian general as he leads 59,000 men and 37 elephants over the Pyrenees, fights his way across Gaul,…
Keeping Time
Episode 3 of Mysteries of Modern Physics: Time Series
How do we measure the passage of time? Discover that practical concerns have driven the search for more and more accurate clocks. In the 18th century, the problem of determining longitude was solved with a timepiece of unprecedented accuracy. Today's…
Time’s Arrow
Episode 4 of Mysteries of Modern Physics: Time Series
Embark on the quest that will occupy the rest of the course: Why is there an arrow of time? Explore how memory and aging orient us in time. Then look at irreversible processes, such as an egg breaking or ice…
Time Travel
Episode 19 of Mysteries of Modern Physics: Time Series
Use a simple analogy to understand how a time machine might work. Unlike movie scenarios featuring dematerializing and rematerializing, a real time machine would be a spaceship that moves through all the intervening points between two locations in spacetime. Also…
Episode 21 of Famous Romans
Born a slave, he was exiled from Rome for speaking too freely to the emperor. Despite offers to return, he lived on in a backwater, becoming one of the greatest exponents of that vastly influential approach to life known as…
Time in Quantum Mechanics
Episode 8 of Mysteries of Modern Physics: Time Series
Quantum mechanics is the most precise theory ever invented, yet it leads to startling interpretations of the nature of reality. Probe a quantum state called the collapse of the wave function that may underlie the arrow of time. Are the…
Episode 15 of Famous Romans
The adoption of his great-nephew, Gaius Octavius, is the most compelling evidence of Caesar's foresight. Only 19 at the time of Caesar's death, as the princeps (First Citizen), Augustus would secure centuries of unprecedented peace and prosperity.
The Second Law of Thermodynamics
Episode 5 of Mysteries of Modern Physics: Time Series
Trace the history of the second law of thermodynamics, considered by many physicists to be the one law of physics most likely to survive unaltered for the next thousand years. The second law says that entropy--the degree of disorder in…
Episode 17 of Famous Romans
A sign of the Augustan system's genius was its ability to survive eccentric or even mad emperors. History is fascinated by those emperors' excesses, which indeed can be highly instructive. Claudius, for all his oddness, was a shrewd and able…
Marcus Aurelius
Episode 24 of Famous Romans
With Marcus Aurelius, a Stoic wore the imperial purple. No emperor was more dedicated or humane. His "Meditations" remain a beacon for all who would go through life with honesty and compassion. But how did he fare as a ruler?
Curved Spacetime and Black Holes
Episode 18 of Mysteries of Modern Physics: Time Series
By developing a general theory of relativity incorporating gravity, Einstein launched a revolution in our understanding of the universe. Trace how his idea that gravity results from the warping of spacetime led to the discovery of black holes and the…
Time Reversal in Particle Physics
Episode 7 of Mysteries of Modern Physics: Time Series
Explore advances in physics since Newton's time that reveal exceptions to the rule that interactions between moving particles are fully reversible. Could irreversible reactions between elementary particles explain the arrow of time? Weigh the evidence for and against this view.
Scipio Africanus the Elder
Episode 5 of Famous Romans
The son of the consul of 218 B.C., Africanus earned his sobriquet by crushing Hannibal in 202 at Zama (now Tunisia), one of the most decisive battles in world history. Here we compare Scipio and Hannibal and the lessons they…