time dilation

A PBS Space Time episode hosted by Gabe Perez-Giz on the nature of spacetime and whether space and time are fundamental. It builds up reference frames and causality in a short, dense format.

PBS Space Time explores whether time causes gravity, explaining that gravity does not truly warp the flow of time but arises from time gradients. It revisits how gravitational time dilation works in general relativity.

Tom Scott explains for Computerphile why handling time and timezones in code is so hard, walking through a simple web app that computes how long ago something happened. It covers the quirks of timezones and calendars and ends in an exasperated rant.

An RSA Animate illustrating a lecture by psychologist Philip Zimbardo on how people's perspectives on time (past, present, future) shape work, health and well-being.

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.

A PBS Space Time episode asking whether time began at the Big Bang. It explains that the Big Bang is not what most people were taught and what 'start' of the universe really means.

PBS Space Time explains the quantum eraser experiment, in which erasing which-path information appears to reverse causality in a double-slit setup. It discusses what this means for quantum mechanics.

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 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.

PBS Space Time explains what happens as you approach and cross a black hole's event horizon, using Penrose diagrams and light cones as the tool for understanding spacetime there.

A PBS Space Time episode asking what black holes really are and whether events can happen inside them. It covers event horizons, time dilation and common misconceptions about black holes.

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.

A PBS Space Time episode explaining why faster-than-light travel is equivalent to travelling back in time, using relativity and Minkowski diagrams for different observers.

Technology Connections explains how LED traffic lights, which do not melt snow, drew complaints and were blamed for accidents. He uses it to illustrate the 'but sometimes' fallacy against new technology.

Mathologer shows how times table diagrams on a circle produce cardioids and other curves connected to the Mandelbrot set. He explains the patterns and links to a tool for making your own diagrams.

A Technology Connections video essay on how analog and digital clocks shape different mental models of time, with the minute hand acting as a progress indicator.

A short Tracklib video visualizing the disco sample that Daft Punk's One More Time is built from. It shows how the track is composed from the original material.

A minutephysics explainer on the twins paradox in special relativity. It shows why the traveling twin ends up younger and how acceleration resolves the paradox.

CGP Grey explains the mess of Daylight Saving Time, including its dubious energy savings and the odd cases like Arizona that opt out. It is a short, simple explainer.

A PBS Space Time episode introducing de Broglie-Bohm pilot wave theory, an interpretation of quantum mechanics that avoids much of the strangeness of the mainstream views. It is aimed at curious lay viewers.

PBS Space Time explains the Bohr-Einstein debate over quantum mechanics and how quantum entanglement settled it. It covers the weirdness of measurement and nonlocal correlations.

PBS Space Time explains how spacetime geometry and light cones determine the order of events and what can cause what. It visualizes causality in special relativity.

PBS Space Time argues that the speed of light is better understood as the speed of causality, the universal limit on how fast cause and effect propagate. Light travels at that speed because it is massless, but the limit itself is a property of spacetime.

A PBS Space Time episode asking whether Venus would be a better colonization target than Mars. It covers Venus's habitable altitudes, floating balloon habitats, and the term surfacism.

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.

A PBS Space Time episode on how the Higgs mechanism gives particles mass, prompted by Fermilab's heavier-than-expected W boson measurement. It goes beyond the usual pop-science treatment without heavy math.

PBS Space Time explains Stephen Hawking's prediction of Hawking radiation and how black holes can emit radiation and slowly evaporate. It goes beyond the common particle-antiparticle analogy.

PBS Space Time examines the interstellar object 'Oumuamua and the popular theories about it, including the light-sail hypothesis. It argues that a natural rock is the likeliest explanation.

A PBS Space Time episode explaining the holographic principle: the idea that our 3+1 dimensional universe may be described by information on a lower-dimensional boundary. It walks through black hole entropy and the AdS/CFT correspondence.

PBS Space Time episode on the black hole information paradox, covering how black holes seem to destroy information, the no-hair conjecture and the proposed role of the event horizon. It is part of a series on black holes.

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.

PBS Space Time examines Roger Penrose's idea that consciousness arises from quantum processes in the brain, and reviews new evidence about microtubules. It ends with an estimate of what replicating consciousness would demand.

A PBS Space Time episode on fuzzballs, the string-theory proposal for black holes that replaces the singularity with a tangle of strings. It explains why black holes seem to both have to exist and break known physics.

A PBS Space Time episode on how gravitational wave observations of a neutron star merger, GW170817, can limit the number of spacetime dimensions. It is based on a 2018 paper.

PBS Space Time considers whether life could be based on silicon instead of carbon, comparing the two elements' chemistry and why silicon is the most plausible alternative.

A PBS Space Time episode asking whether our universe could sit inside a black hole. It covers what physicists think happens inside black holes and the arguments for and against this idea.

PBS Space Time examines the Silurian hypothesis, the idea that an industrial civilization could have existed on Earth before humans. It looks at what traces such a civilization might leave in the geological record.

PBS Space Time surveys five realistic options for interstellar travel, from conventional rocket fuel to antimatter and nuclear pulse propulsion. The options rely only on known physics.

Veritasium explains, with expert input, that in general relativity gravity is not a force and objects follow straight paths through curved spacetime, including why standing on the ground means you are accelerating.

A Kurzgesagt animated explainer on whether aging could be cured within our lifetimes, made with Lifespan.io and the LEAF foundation. It introduces the idea of treating aging as a medical problem.