What Is the Kardashev Scale and Where Does Humanity Rank?

The Kardashev scale is a way to rank civilisations by how much energy they can use. Soviet astronomer Nikolai Kardashev proposed it in 1964. Type I uses all the energy available on its home planet, Type II harnesses its whole star, and Type III controls the energy of an entire galaxy. Humanity hasn't reached Type I yet.

What are the Kardashev scale types?

Type	Energy source	Rough power
I	All the energy reaching its planet	~10¹⁶–10¹⁷ watts
II	Its entire star	~10²⁶ watts
III	Its whole galaxy	~10³⁶–10³⁷ watts

Kardashev introduced the idea in a 1964 paper on how to detect extraterrestrial civilisations by their energy output.

Where does humanity rank on the Kardashev scale?

Carl Sagan suggested a formula that gives fractional ratings. On that formula, humanity scores roughly 0.7, with estimates varying by year and by which energy figures are used. Global primary energy use is roughly 19–20 terawatts, which is still far below Type I.

What is a Dyson sphere?

It is a hypothetical swarm of collectors around a star, described by Freeman Dyson in 1960. It is the classic Type II technology, and astronomers search for its possible infrared heat signature.

Could we reach Type I?

Futurists such as Michio Kaku have estimated it could take a century or more. That is a prediction, not a fact, and it depends on energy growth that no one can forecast with confidence.

FAQ

Is there a Type IV? Some writers have proposed it, but it wasn't part of Kardashev's original scale.

Who created the Kardashev scale? Nikolai Kardashev, in 1964.

Is it scientific? It is a thought tool for SETI rather than a measured law.

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Sources

• 01en.wikipedia.org/wiki/Kardashev_scale
• 02adsabs.harvard.edu/full/1964SvA.....8..217K
• 03en.wikipedia.org/wiki/Dyson_sphere
• 04ourworldindata.org/energy-production-consumption