The Speed of Everything
A logarithmic journey through velocity — from the imperceptible drift of continents to the absolute cosmic speed limit of light.
Speeds You Know
You are an expert on speed. You've been calibrating your internal speedometer since birth — the rhythm of a walk, the lurch of acceleration, the blur outside a car window. But your expertise covers a vanishingly small slice of reality.
The Familiar Race
How fast are the speeds you already know?
Walking to flying. 1.4 to 250 m/s. That's your entire lived experience of speed — roughly two orders of magnitude. The universe operates across seventeen.
Now let's go the other direction. Below walking speed, below crawling speed, below anything you can see happening — the universe is full of motion so slow it's invisible.
The Imperceptibly Slow
Your hair grows at five nanometers per second. While you read this sentence, each strand on your head extended by roughly the width of a DNA molecule. And here's the strange part: that's almost exactly the speed at which North America is drifting away from Europe.
The Slow Parade
How far do the slowest things travel? Change the time scale.
These processes shaped the planet. Continental drift at 2.5 cm/year has moved entire oceans over 200 million years. Slow doesn't mean unimportant — it means patient.
Humans are not content with the speeds nature gave us. We've spent centuries engineering our way past every limit.
Breaking Barriers
In 1947, Chuck Yeager flew the Bell X-1 past Mach 1 — 343 m/s — and broke the sound barrier. Since then, we've built bullets that travel at Mach 2.7, spacecraft that orbit at 7,660 m/s, and a solar probe that holds the speed record for any human-made object.
Sound vs. Light
A thunderstorm 1 km away
Light crosses 1 km in 3.3 microseconds. Sound takes 2.9 seconds — nearly a million times slower. That's why you see lightning before you hear thunder.
The Parker Solar Probe — humanity's speed record at 192,000 m/s — is still only 0.064% of the speed of light. Even our fastest creation is a rounding error compared to what the universe considers ordinary.
Here's a secret: you are not sitting still. You have never been sitting still. You are, right now, hurtling through space at hundreds of kilometers per second.
Cosmic Velocities
The Earth rotates at 465 m/s at the equator. It orbits the Sun at 29,800 m/s. The solar system orbits the galaxy at 220,000 m/s. And the Milky Way itself is moving toward the Great Attractor at ~600,000 m/s relative to the cosmic microwave background.
The Cosmic Speedometer
You are never sitting still. These velocities stack.
“How fast am I going?” has no single answer. All motion is relative — your speed depends on your reference frame. You're simultaneously sitting still and hurtling at 600 km/s. Both are true.
There is a speed that nothing with mass can ever reach. It is not merely fast — it is the speed limit of causality itself.
The Speed of Light
Since 1983, the metre is defined by this number: 299,792,458 m/s. The speed of light is not just very fast — it is the absolute maximum speed at which information, energy, or causality can propagate through space. Nothing with mass can reach it; approaching it requires infinite energy.
And yet, at cosmic scales, even light is frustratingly slow. We see the Sun as it was 8 minutes ago. The nearest star is 4.24 light-years away. We never see the universe in real time.
Light Delay Explorer
Select a destination. Watch the photon travel.
Time Dilation
As you approach c, your clock slows down relative to an observer.
Now step back. All the way back. Let's see everything at once.
The Full Spectrum
A logarithmic scale is the only way to see the full picture. On a normal (linear) scale, continental drift would be an invisible dot, and the speed of light would be miles off the edge of your screen. On a log scale, each equal step is a multiplication by 10 — and every speed finds its place.
Scroll to travel through 17 orders of magnitude
You live in two orders of magnitude out of seventeen. Your body, your cars, your planes — they occupy a tiny, arbitrary band in a spectrum so vast that seeing it requires a scale where each step is ten times the last.
Speed is not a line from slow to fast. It is a spectrum so vast that we perceive less than 12% of it. And yet, from the patient drift of continents to the absolute finality of light, every speed tells us something about the structure of reality.