Physics
15 pieces · 1.4 hours of reading
The Four Forces That Run Everything
Every event in the universe — a falling apple, a beating heart, sunlight, a magnet, the explosion of a star — is one of just four fundamental forces at work. Four. That's the entire cast. Once you know them, the world reorganizes itself in your mind.
Quick read4 min02Energy: The One Currency of the Universe
Everything that happens — a thought, a sunrise, a sprint, a star exploding — is energy changing form. It's the single currency the entire universe trades in, and it obeys two profound rules that together explain why the past differs from the future, why perpetual motion is impossible, and why you have to eat. Understanding energy is close to understanding how reality works.
Read5 min03Why Time Is Weirder Than You Think
Time feels like the one thing we can trust — a steady, universal beat ticking the same for everyone, everywhere. It's the deepest illusion we live inside. A century ago, physics discovered that time bends, stretches, slows, and may not "flow" at all. This is the strangest and most beautiful thing science has ever found about the world you live in — and it's real, measured, and running in the phone in your pocket.
Read6 min04How Electricity Actually Reaches Your Wall
You flip a switch and light appears, instantly, every time. Behind that ordinary miracle is a river of electrons, a continent-spanning machine, and one beautifully simple law. Here's what's really happening.
Quick readInteractive4 min05Everyday Physics: The Answers Hiding in Plain Sight
Why is the sky blue? Why does ice float? Why does a heavy ship stay up while a coin sinks? These aren't trivia — they're the universe explaining itself in your kitchen, your bathtub, and the sky over your head. Once you can read them, the ordinary world becomes a permanent, free show.
Read5 min06Quantum Mechanics: The Weirdness at the Bottom
Zoom into matter far enough — past atoms, down to electrons and photons — and the ordinary rules of "a thing is somewhere, doing one thing at a time" simply stop applying. Not because we lack better instruments. Because that's not how reality behaves down there. This is the strangest, best-tested theory in the history of science.
ReadInteractive6 min07The Standard Model: What Everything Is Made Of
The Four Forces
Read5 min08The Big Bang & Our Expanding Universe
Every distant galaxy is moving away from us. Not just moving — the farther away it is, the faster it's receding, in a precise, consistent relationship holding in every direction we look. Run that observation backward in time, and it points to one inescapable conclusion: everything, everywhere, used to be impossibly close together.
ReadInteractive5 min09Light & Color: Why the World Looks the Way It Does
Nothing you have ever seen is actually colored. Not the sky, not a leaf, not a sunset. What exists out there is electromagnetic radiation of various wavelengths — color itself is something your brain builds, in real time, out of that raw physical signal. That's not poetry. It's how vision actually works.
ReadInteractive5 min10The Far Future: How the Universe Ends
Thirteen point eight billion years have passed since the Big Bang. That number already strains intuition — human civilization is roughly ten thousand years old, meaning recorded history is a rounding error against the universe's age. And yet, on the timescales this piece is about to describe, 13.8 billion years is not even the beginning. It is a fraction of a fraction of a fraction of a percent of how long the universe has left. This is a tour of deep future time, built on real physics and honest about exactly where that physics runs out.
Read7 min11Why the Moon Keeps Falling
The Moon is falling towards the Earth right now, about 1.4 millimetres every second. So is the International Space Station, with people inside. They never hit the ground, because they are moving sideways so fast that the ground keeps curving away beneath them.
ReadInteractive5 min12Entropy and Time's Arrow
Every collision between molecules works just as well backwards as forwards. Yet milk stirs into coffee and never stirs back out. The reason is a counting argument so simple you can run it in your browser, and behind it hides one of the deepest open questions in physics.
ReadInteractive6 min13When Two Notes Meet
Play two notes that are almost, but not quite, the same and you hear a slow throbbing, wah-wah-wah. Musicians tune by it. Line two identical notes up exactly out of step and they cancel into silence, which is how noise-cancelling headphones work. Both come from one simple rule: waves add.
ReadInteractive6 min14How a Nuclear Reactor Works
A nuclear power station is, at heart, a kettle: it boils water to spin a turbine. What makes it extraordinary is the fire under the kettle, a chain reaction that could double in a fraction of a second. It can be steered at all only because of one easily overlooked fact: a tiny fraction of its neutrons arrive late.
ReadInteractive7 min15The Physics of the Greenhouse Effect
By a straightforward calculation, the Earth's surface should average about −18 °C, cold enough to freeze the oceans. It actually averages about 15 °C. The 33-degree difference is the greenhouse effect. It is older than humanity and it is the reason the planet is liveable. The modern question is only how much extra of it we are adding, and the physics that answers it is two centuries old.
Read7 min