TheKardashevTimeline
In 1964 the astronomer Nikolai Kardashev proposed ranking civilizations by a single number: the power they command. After a million years of fire, coal and atoms, humanity still hasn’t reached the first rung.
Scroll to climb, from the first fire to the cosmic web
One number for a whole civilization
Kardashev was listening for alien radio signals, and he wanted to know how loud a civilization could possibly be. Energy sets the limit, so he sorted civilizations by the energy they control: a planet’s worth for Type I, a star’s for Type II, a galaxy’s for Type III.
Carl Sagan later turned the three types into a continuous dial.
0Below planetary
A million years below the first rung
Every civilization on Earth has lived on scraps of the planet’s energy budget: sunlight trapped in plants, fossil sunlight in coal, a trickle from rivers, wind and atoms. As you scroll, the globe turns to where each step happened.
-
~1,000,000 years ago
Fire
Wonderwerk Cave, South Africa
Ash and burnt bone deep inside a cave: some of the oldest firm evidence of fire in human hands. A species starts burning energy outside its own body.
K ≈ 0.20 rough estimate
-
~11,000 years ago
Farming
The Fertile Crescent
Wheat and barley are domesticated. A field is a solar collector you can eat, and from here population and energy use compound together.
K ≈ 0.34 rough estimate
-
1712
The steam engine
Dudley, England
Thomas Newcomen’s engine drains a coal mine by burning coal. Sunlight stored underground for 300 million years goes to work.
K ≈ 0.56
-
1882
The grid
New York
Pearl Street Station switches on in Lower Manhattan. Energy stops being something you haul and starts arriving by wire.
K ≈ 0.60
-
1954
Atoms and silicon
Obninsk, Soviet Union
The world’s first nuclear power plant feeds a public grid. Two months earlier, Bell Labs unveiled the silicon solar cell. Two of the sources that could carry us to Type I arrive in the same year.
K ≈ 0.66
-
1964
The ruler
Byurakan, Soviet Armenia
At the first Soviet conference on extraterrestrial civilizations, Nikolai Kardashev presents his scale. By his original numbers, about 4 × 1012 W for Type I, humanity already qualified.
K ≈ 0.67
-
1973
The dial
Ithaca, New York
Carl Sagan redraws the scale as a smooth dial, raises the bar for Type I to 1016 W, and scores humanity at about 0.7.
K ≈ 0.69
-
2022
Ignition
Livermore, California
At the National Ignition Facility, 2.05 MJ of laser light sparks 3.15 MJ of fusion: the first time a fusion experiment gave back more energy than was fired into it.
K ≈ 0.73
-
2026
Today
Everywhere at once
About 20 terawatts, day and night. Sunlight hands Earth nearly 9,000 times that much, and we are using roughly 0.2% of a Type I budget.
K ≈ 0.73
IPlanetary
Use everything a planet offers
- Power
- 1016 W
- Versus today
- ×500
- Arrival, est.
- 2200–2400
A Type I civilization runs on the full energy budget of its home world. Most of it is sunlight: Earth intercepts about 174,000 terawatts. Wind, tides, geothermal heat and fusion fuel from seawater make up the rest.
Picture rings of collectors in orbit beaming power down, and a single planetary grid where night is just a time zone.
The catch is heat
Every watt ends up as waste heat. Burn 1016 W on the ground and that alone would warm the planet by several degrees, so a real Type I civilization probably moves its heaviest industry off-world. One 2022 study put humanity’s arrival at the year 2371.
×10,000,000,000
The next rung takes ten billion times more power. To reach it, a civilization has to leave its planet.
IIStellar
Wrap a star
- Power
- 1026 W
- The Sun
- 3.8 × 1026 W
- Arrival, est.
- Thousands of years
Stop collecting the sliver of sunlight that happens to land on your planet. Collect all of it. In 1960 Freeman Dyson argued that a long-lived technological species would eventually surround its star with collectors, and that astronomers could spot one by its infrared glow.
A swarm, not a shell
A solid sphere around a star would be unstable, and no known material could hold it together. The workable version is a swarm: billions of independent collectors, each on its own orbit. One well-known blueprint takes Mercury apart for raw material.
How we’d spot one
A finished swarm dims its star in visible light and glows in the infrared, shedding waste heat at a few hundred kelvin. In 2024 Project Hephaistos sifted about five million stars for that signature and flagged seven candidates. Follow-up observations have since tied at least one of them to a galaxy far in the background.
×10,000,000,000
From one star to a few hundred billion.
IIIGalactic
Take the galaxy, one star at a time
- Power
- 1036 W
- Milky Way
- ~1037 W
- Arrival, est.
- 100,000+ years
A Type III civilization harnesses the light of an entire galaxy. Even with probes flying at a tenth of light speed, crossing the Milky Way takes about a million years. So this is less an empire than a slow tide: self-copying machines settling one star system after another.
The great silence
The Milky Way is more than 13 billion years old. Something spreading at 1% of light speed could fill it in about ten million years, a blink on that clock. So where is everybody? Enrico Fermi asked exactly that over lunch in 1950.
In 2015 the Ĝ survey checked about 100,000 galaxies for the heat of a civilization using most of its starlight, and found none.
×10,000,000,000
Kardashev’s ladder ends at three. Others kept adding rungs.
IVUniversalSpeculative
Tap the cosmic web
- Power
- 1046 W
- Equal to
- ~1 billion galaxies
- Arrival, est.
- Unknown
A Type IV civilization would draw power across the cosmic web itself, the filaments of galaxies that stretch across the observable universe. Proposals involve supermassive black holes, whole galaxy clusters, or physics nobody has found yet.
The universe is leaving
Cosmic expansion is speeding up. More than 90% of the galaxies we can see are already out of reach, even at light speed, and more slip over the horizon every year. A Type IV civilization would be racing the expansion of space itself.
VMultiversalSpeculative
Reach past the universe
- Power
- Off the scale
- Needs
- Universes beyond ours
The top rung of the extended ladders belongs to a civilization that draws on other universes. Nobody knows whether other universes exist, let alone whether anything could cross between them. Up here the scale stops measuring watts and starts measuring imagination.
Back to 0.73
Everything above the first rung is a projection. Only one civilization has ever been measured on this scale, and it lives on the planet you just fell back to.
When do we get there?
Pick how fast humanity’s energy use grows each year and see where compounding takes us. Over the past century, growth averaged a little over 2% a year.
| Type I1016 W | |
|---|---|
| Type II1026 W | |
| Type III1036 W |
Pure compoundingLight-speed ceilingReachable path
0.27 to go
Closing that gap means five hundred times more power than we use today. It is also the only rung built entirely from physics we already understand: sunlight, fission, fusion, storage, transmission lines and launch pads.
Where the timeline goes next is up to us.