The Fermi Paradox: A 10 Step Guide To Finding Aliens

6. The Kardashev Scale

There's this thing call the Kardashev scale, originally devised by Soviet astronomer Nikolai Kardashev, that we use to roughly categorise civilisations by the way they extract energy from their surroundings.

The core Kardashev scale has three tiers: Type I: The ability to use all of the energy available on the civilisation's home planet (nuclear fusion, antimatter and renewable) Type II: The ability to use all of the energy of the host star (Dyson Sphere, Star Lifting) Type III: The ability to harness all of the energy in the galaxy (Quasars, gamma ray bursts, White Holes)

According to this scale, we're not even a Type I civilisation yet (Carl Sagan's calculations puts us at about 0.7), but the ones we're looking for are more likely to be a Type II or even Type III as they're likely to be galactic colonists, leaving a bigger footprint on the galaxy that would be easier to spot from all the way down here on Earth.

If we speculate (and if the Drake equation has taught us anything, it's that all we can do is speculate) as conservatively as we possibly can and say that, 0.1% of stars in the Milky Way harbour life (that's 1 million for those playing along at home).

Then we say that 0.1% of those planets give rise to an intelligent civilisation (1,000) and 0.1% of those advance to the point of becoming a Type III civilisation, that means we must have at least one galaxy-colonising civilisation flying around the Milky Way, even with those outrageously conservative estimates.

If we bump each of those values up to just 1% probability then we get 10,000 super-advanced civilisations flying around just our galaxy. Now, as far as we can tell, we don't. So, the next question is why not?