channel 4

An 8-minute explainer on the Lightning Network and how it relates to Segwit, Bitcoin and Litecoin. It covers how off-chain payment channels route payments to scale blockchain transactions.

Moon Channel, run by a lawyer, explains the legal basis for emulation, including the history of emulation case law and Nintendo's takedown of Dolphin's Steam release. It argues the legality of emulators is more fragile than most people assume.

A PBS Space Time episode explaining how space and time swap roles inside a black hole's event horizon. It is part of the channel's black hole series.

agadmator walks through a game in which DeepMind's AlphaZero beat Stockfish, ending in a famous zugzwang that leaves the engine helpless. He gives commentary on the moves.

A 1951 Bell System training film showing how telephone calls are routed through a step-by-step (Strowger) switching office.

Pannenkoek2012's commentated tool-assisted Super Mario 64 run collecting the Watch for Rolling Rocks star with half an A press, using parallel universes and QPU movement. The video is marked outdated in favor of a newer version.

Bill Hammack of Engineer Guy explains the engineering behind the aluminum beverage can: why it is cylindrical, how it is manufactured, why it narrows at the top, the double seam, and how the pull tab works.

A short BicycleDutch video on how the Netherlands got its cycling infrastructure, including the 1970s protests and the shift away from car-centric planning. The channel later published an updated version.

Robert Miles explains the orthogonality thesis: how an agent can be highly intelligent while pursuing goals that seem stupid or alien to humans. He separates intelligence from goals and touches on the stamp-collector example.

Technology Connections explains how old-fashioned non-electronic rice cookers work, using a magnet and spring switch tripped by the Curie point. It shows the thermodynamics and magnetism behind a simple appliance.

Technology Connections explains how the simple American drip coffee maker works, including the bimetal valve and bubble-pump heating, and compares the original Mr. Coffee with modern machines.

An older 3Blue1Brown video on why topology matters, built around the inscribed rectangle problem. It walks through how tori and Mobius strips appear in the solution. The channel later replaced it with an updated version.

An Isaac Arthur episode on civilizations in the dark, post-stellar universe, including black hole farming, accretion disks and the Penrose process as energy sources.

Captain Disillusion debunks a viral Chinese invisibility cloak video while parodying popular educational channels. Along the way he explains chroma keying and green screen techniques.

A PBS Space Time episode asking what matter, mass, and energy really are, starting with inertial versus gravitational mass and what mass-energy equivalence means.

PBS Space Time explains the Hubble constant tension, in which two precise, independent methods of measuring the universe's expansion rate disagree. It covers why this calls some standard cosmology into question.

PBS Space Time introduces Miguel Alcubierre's warp drive, explaining how spacetime itself could be warped rather than moving a ship through it, and whether it is physically possible.

Not Just Bikes compares the same cycling trip to a hardware store in Calgary and in Amsterdam, using a 'plus 1 minus 2' format. It shows how street design shapes how safe and practical cycling is.

Looking Glass Universe explains de Broglie-Bohm pilot wave theory (Bohmian mechanics) as an alternative to the standard interpretation of quantum mechanics. The video lays out the pros and cons of the theory and links to related videos on contextuality and entanglement.

Astrophysicist David Kipping presents the halo drive, a proposed way to propel a starship to a good fraction of light speed by gaining energy from a black hole. The video is based on his peer-reviewed paper and explains why energy is the main obstacle to interstellar flight.

Huygens Optics shows through a laser interference experiment that the question of a photon's size is really about coherence length. It argues that photons exist as energy exchanges between radiation and matter, not as little particles in free space.

PBS Space Time explains the Higgs field and how the Higgs mechanism gives particles mass within quantum field theory. It is a ten-minute overview for a lay audience.

Huygens Optics explores the idea that space is a non-linear elastic medium, and uses simulations to show how wave energy might be confined locally into particle-like objects. It touches on inertia, the Schwinger limit and the vacuum as a medium.

Robert Miles introduces the first of several videos on the paper 'Concrete Problems in AI Safety', focusing on how AI systems can cause accidental negative side effects. It explains the problem in accessible terms.

A PBS Space Time episode explaining the Fermilab Muon g-2 results and why a discrepancy with the Standard Model prediction could point to new physics.

A short, sarcastic Half as Interesting video about a tiny freight railway in Canada built to exploit a shipping regulation loophole. It explains how a track just 100 feet long counted as a railway.

Technology Connections explains why car turn signals appear to drift out of sync at stoplights and how thermal and other flasher designs work. It also covers how synchronization could be achieved.

Chubbyemu narrates the true case of a professor who spilled two drops of dimethylmercury on her hand and suffered fatal neurological damage.

Isaac Arthur examines Dyson spheres and swarms, including common myths and misconceptions. He covers uses such as interstellar travel, black hole generation, and computing large enough to simulate universes.

Dr. John Campbell reviews studies on vitamin D and immunity, including research on respiratory infections, during the early COVID-19 period.

Not Just Bikes visits Paris to see how Mayor Anne Hidalgo's policies are turning it into a '100% cyclable' city. It looks at the changes that took space from cars for bikes and people.