How to Measure the Power of Alien Civilizations Using the Kardashev Scale
We have yet to make contact with an extraterrestrial civilization. If they’re out there - and surely they must be - we haven’t the foggiest idea what they might be like. Or do we?
Given what we know about the universe and our own civilization, we should be able to make some educated guesses. And in fact, several decades ago, a Russian astrophysicist came up with a classification system to describe hypothetical aliens. Here’s how the Kardashev Scale works.
The Kardashev scale is a method of measuring a civilization’s level of technological advancement, based on the amount of energy a civilization is able to utilize. The scale has three designated categories called Type I, II, and III.
Kardashev wrote that a Type I civilization would be at a “technological level close to the level presently attained on the Earth, with energy consumption ~4 x 1019 erg/sec.” That’s about 4 x 1012 Watts.
Kardashev’s initial intention was to describe a civilization not too far removed from our own (again, for the purpose of rating its communicative capacities) but one that has yet to exploit all of the solar system’s resources.
A Type I is typically associated with a hypothetical civilization that has harnessed all the power available to it on its home planet. For a civilization to attain Type I status, therefore, it needs to capture all of the solar energy that reaches the planet, and all the other forms of energy it produces as well, like thermal, hydro, wind, ocean, and so on.
Quite obviously, we are not a Type I civilization. Not even close. But physicist Michio Kaku predicts that we’ll get there eventually, perhaps in a century or two.
For an extraterrestial intelligence (ETI) to reach K2, it would need to capture the entire energy output of its parent star. The best way to achieve this, of course, is to build a Dyson Sphere.
Conjured by Freeman Dyson in 1959, this hypothetical megastructure would envelope a star at a distance of 1 AU and cover an inconceivably large area of 2.72 x 1017 km2, which is around 600 million times the surface area of the Earth. The sun has an energy output of around 4 x 1026 Watts, of which most would be available to do useful work.
It’s difficult to predict when we ourselves could become a Type II, but physicist Stuart Armstrong says we could start the project in a few decades.
With all this energy, an advanced civilization - probably one that’s postbiological in nature - would use it to power its supercomputers and fuel its other endeavors (like interstellar colonization waves).
Which leads to the next increment in the scale. Kardashev described a Type III like this: “A civilization in possession of energy on the scale of its own galaxy, with energy consumption at ~4 x 1044 erg/sec.” Needless to say, that’s a tremendous amount of energy - somewhere between 1036 Watts to 1037 Watts.
Every inch of a K3 galaxy would be colonized, with every scrap of matter exploited for energy. From the perspective of an outside observer, a galaxy occupied by a K3 civ would appear completely invisible, save for the heat leakage which would register in the far infrared (around 10 microns in wavelength).
It would take a civilization anywhere from 100,000 to a million years to transition itself from a Type II to a Type III. From our vantage point, this would look like a hole in a galaxy, or an inexplicably large swath of open space.
Type IV and V
Though Kardashev never went past a Type III, others have taken his idea to the next level. A Type IV would be an ETI (or merging groups of ETIs) that has harnessed all the power of a galactic supercluster, and a type V would have the entire power of the universe at its disposal. Such hypothetical civilizations have either transcended their universe of origin or arose within a multiverse or other higher-order membrane of existence, and are capable of universe-scale manipulation of individual discrete universes from an external frame of reference.
First and foremost, and stating the obvious, no empirical evidence exists indicating the presence of K2 or K3 civilizations in our galaxy and/or galactic neighborhood. In fact, the Fermi Paradox would indicate that civilizations never become migratory, thus making a Type III very unlikely.
Another problem with the Kardashev Scale is the assumption that advanced civilizations have an insatiable appetite for energy. No doubt, a K3 civ seems a bit excessive. It’s not a stretch to suggest that a Type II civilization might be as far as these things go. Even a Type I for that matter. But we don’t know for sure. So in the meantime, let’s be sure to keep listening and looking.
Always fascinated by this subject.