relativity

The first of Richard Feynman's 1964 Cornell Messenger Lectures, The Character of Physical Law, focusing on the law of gravitation. Feynman builds up from planetary motion to the nature of physical laws.

David Tong, a Cambridge theoretical physicist, explains at the Royal Institution that the fundamental building blocks of nature are quantum fields rather than particles. He covers what we know about these fields and how they fit into the Standard Model.

Physicist Carlo Rovelli gives a public lecture at the Royal Institution on how our understanding of time has changed, from Boltzmann and Einstein to quantum theory and loop quantum gravity. He blends physics, philosophy and art to argue that time is stranger than everyday intuition suggests.

Sean Carroll introduces his video series on the biggest ideas in physics, such as symmetry, space and matter, as informal discussions with follow-up Q&A videos. This is the short opening video of the series.

Harvard Belfer Center lecture by Matthew Bunn explaining how nuclear bombs work, including fission and fusion weapons and which parts of bomb-making are hard. It is part 1 of 2 in the Nuclear 101 series.

Eric Weinstein's roughly three-hour presentation of Geometric Unity, his proposed theory unifying physics, given as a special episode of The Portal. It includes clarifications at the end.

A 78-minute Richard Feynman lecture of anecdotes about working at Los Alamos on the Manhattan Project, followed by about ten minutes of audience Q&A in which he tells three safe-cracking stories.

A segment from Carl Sagan's original Cosmos explaining the fourth spatial dimension through analogy with a two-dimensional world and shadow projection.

The first lecture of Leonard Susskind's Stanford Continuing Studies course on modern physics, beginning with classical mechanics. It is the start of a six-quarter sequence on the theoretical foundations of physics.

A one-minute clip of Richard Feynman describing the scientific method: guess a law, compute its consequences, and compare with experiment. If it disagrees with experiment, it is wrong.

Douglas Hofstadter lectures at Uppsala University on how analogy and daring thinking drove Einstein's discovery of light quanta. He argues deep insight in physics comes from imaginative leaps rather than rigid logic.

Leonard Susskind's Santa Fe Institute talk on the arrow of time: why the past differs from the future when physics equations are time-symmetric. He covers entropy, cosmology and Boltzmann brains.

Nathan Kutz presents the spatio-temporal dynamics of rotating detonation rocket engines, including combustion fronts that behave like solitons. He shows a bifurcation analysis of a multiscale model that captures the main features.

A one-minute clip from Richard Feynman's 1979 Auckland lecture in which he answers whether you see an object or only its light. It is a short, playful take on perception and on the use of philosophy.

A detailed 40-minute explanation of the ultraviolet catastrophe, covering Rayleigh and Jeans' classical treatment of blackbody radiation and Planck's quantum hypothesis. It follows the Eisberg and Resnick textbook treatment.

A short clip of Richard Feynman on the difference between merely knowing how to reason mathematically and understanding why physical theories work. He discusses holding multiple equivalent ideas and guessing new laws.

Part 2 of Richard Feynman's Messenger Lectures at Cornell, The Character of Physical Law, on the relation of mathematics to physics. He explains why understanding nature requires mathematics.

The first of Richard Feynman's 1964 Messenger Lectures at Cornell, 'The Character of Physical Law', covering the law of gravitation. Feynman traces the history from Kepler and Newton to the universality of the inverse-square law. The recording is an older one with weak audio.

A recording of Richard Feynman's talk on the possibilities of manipulating matter at very small scales, widely seen as an early vision of nanotechnology. This is a later version of his 1959 "There's Plenty of Room at the Bottom" lecture.

A clip of Richard Feynman contrasting the Greek and Babylonian traditions of mathematical reasoning. It compares the axiomatic approach of mathematicians with how physicists use mathematics.

Royal Institution lecture by Dr Kate Lancaster on the most powerful lasers in the world and the extreme conditions they create. It includes live demonstrations and covers applications from industry to fusion.

An excerpt of Richard Feynman's 1985 lecture Q&A about whether machines can think. He discusses the difficulty of defining what computers can never do and compares machine intelligence to machines that don't copy animals.

A talk by Eric Weinstein on gauge theory and its possible application to economics and inflation. It proposes extending the Wu-Yang dictionary into a geometric tool beyond physics.