Relativity and Spacetime: The Best Science Videos on Einstein, Time, and Gravity
See our guide to Relativity for the full theory, and Astronomy for the black holes and stars these films explore.
The Cosmic Speed Limit and the Nature of Time
Relativity starts from one strange fact: the speed of light is the same for everyone, and nothing outruns it. Follow that to its conclusions and time itself stops being what you thought.
There Is Something Faster Than Light
The title is a provocation. Veritasium uses the famous argument between Einstein and Bohr to explore what genuinely can and cannot travel faster than light, the cosmic speed limit at the heart of relativity, and why quantum entanglement does not actually break it. The most-watched video in this entire library, and deservedly so.
Read next: Relativity Explained.
Time May Not Exist
Relativity already showed that time is not universal, it runs slower at speed and in strong gravity. Arvin Ash pushes into the more radical idea that time may not be a fundamental ingredient of reality at all. A genuine mind-stretcher that stays grounded in real physics.
Read next: Relativity Explained.
Black Holes and Warped Spacetime
The clearest place to see relativity at work is where gravity is strongest. These two go to the black holes that bend spacetime to the breaking point.
Tracing the Abyss: The Spacetime of a Supermassive Black Hole
Nobel laureate Andrea Ghez spent decades tracking the orbits of stars around the black hole at the center of our galaxy. This is the story of that work and what it proved about warped spacetime, told by the scientist who did it.
Read next: Astronomy Explained.
Did Einstein Crack the Biggest Problem in Physics, and Not Know It?
Brian Greene and a team of researchers use Google's quantum computer to probe quantum gravity, the unfinished business of uniting Einstein's relativity with the quantum world. A look at exactly where relativity runs out and something new has to take over.
Read next: Relativity Explained.
Gravity at the Extremes
This pair comes from the World Science Festival's "Beyond Einstein" series, which pushes gravity to its limits to see where the surprises hide.
Beyond Einstein: Gravitational Rainbows
Part of a series on gravity pushed to extremes, covering how gravity bends light, the puzzle of dark energy, and the edge cases where Einstein's theory makes its strangest predictions. Visually rich and conceptually deep.
Read next: Relativity Explained.
Beyond Einstein: Gravitational Echoes
Just as sound can echo off a distant cliff, light and waves can echo off black holes. This explores what those echoes reveal about the most extreme objects in the universe, and how researchers are learning to listen for them.
Read next: Astronomy Explained.