Mad About Science: The Kardashev scale, Part II

By Brenden Bobby
Reader Columnist

Last week, we learned about what kinds of civilizations could exist in the vast expanse of space and what kind of technology humans would need in order to achieve the lowest two rungs on the Kardashev scale.

In case you missed last week’s article, the Kardashev scale was proposed by Russian astronomer Nikolai Kardashev in 1964. Its purpose was to hypothesize a means in grading potential spacefaring civilizations based on their energy consumption. Type I civilizations would use all of the energy received by their planet from their home star. Type II civilizations would use all of the energy produced by their home star, using something called a Dyson sphere.

So what about Type III civilizations?

A Dyson sphere. Courtesy photo.

A Type III civilization would use all of the energy produced by the galaxy within which it resides, or more precisely, would be able to reproduce the luminosity of its home galaxy. This means it would need to output the same amount of energy as hundreds of millions of stars.

Energy production on this scale would be absolutely staggering and borders on the impossible for humans to comprehend. The diameter of the Milky Way Galaxy is about 106,000 light years, which you can multiply by six trillion in order to find out just how many miles wide our galaxy is. This means that a Type III civilization would need to be 106,000 years old at a bare minimum when just accounting for the amount of time it would need to spread to every star in its galaxy, nevermind the time commitment of building a Dyson sphere around each and every star.

Type III civilizations become more complicated when factoring in the logistics of traveling over the span of light years to deliver supplies to new stars. What would this process look like?

As we’ve never observed a Type III civilization, we have no way to be sure, but we can guess.

Any civilization advanced enough to harness the full power of a star must already have some impressive engineering prowess. It’s very likely that an entity like this would use some form of mechanized labor, such as self-replicating nanobots harvested from planets and asteroid fields. These tiny robots would work together in huge synchronized swarms and would operate in a similar manner to Starlings.

Starlings are birds here on Earth that exist in huge colonies, so vast in number they black out the sky in flight. Despite the staggering number of birds, they seem to fly in perfect synchronicity to create wave-like patterns in the sky. It turns out that this trick is pretty simple for the starlings to do. One bird will track nine other birds in its field of view and mark them as vectors in a grid. When part of that vector deforms, they change their flight pattern to match the deformation, which causes another bird’s grid to deform. It’s very likely that simple microscopic robots would behave in a similar fashion, while also carrying supplies to deposit to a structure they are programmed to build.

Let’s imagine for a moment that a Type III civilization sends a colony of engineers and self-replicating robots to a star for the first time. It’s likely that they’re packing light — no colossal colony ships the size of moons like you’d see in science fiction. The energy cost for transporting mass through space grows proportionally to the speed in which it’s traveling. In order for any amount of mass to reach the speed of light, the energy cost becomes infinity, which is more energy than exists in our entire universe by… Well, an infinite amount.

To circumvent this, there are two possibilities that we are aware of that an advanced civilization may be able to use to its advantage when traveling vast distances. The first is an extremely energy-intensive form where a ship could be accelerated to more than 90% of the speed of light. Due to the theory of relativity, any passenger inside of this vehicle would experience the passage of time differently than anything outside of the vehicle. That means if these beings were traveling to a star 10 light years away at 90% of the speed of light, they would experience about a year of time pass inside of the vehicle, but once they arrive at their destination the full 10 years would have passed outside of the vehicle.

The other form of travel would be something akin to a warp drive from Star Trek. A warp drive is kind of like hacking reality to get around the rules. Somehow, a bubble is formed in space and time, within which the ship is tucked and propelled forward, maintaining this bubble. Since you’re technically circumventing time, your passage may seem near-instantaneous once you pop out of the bubble somewhere else. In theory, you should be able to cover vast distances in nanoseconds when properly applied, but this also brings up an interesting paradox related to time. Since you’re manipulating space and time, you technically arrive at the other destination before you’ve departed. Weird, right?

However this civilization reaches this destination, we suspect they’d utilize self-replicating robots that work slowly at first, but exponentially grow in number to quickly harvest raw atomic material and re-apply it into new building materials, likely around the system’s star to create a dyson sphere and a transmitter to beam energy back to wherever home may be.

As you might have guessed, we haven’t actually found any civilization like this in the universe yet. A Dyson sphere should leave a telltale signature: either it’s fully enclosed and producing an immense amount of infrared radiation, or it’s partially obscured and would create some form of radio signal that’s intermittently interrupted at very precise intervals. Scientists thought they observed this just a few years ago before discovering it was a much more mundane phenomenon — likely a planet, either whole or shattered.

However, just because we haven’t found any sign of this yet doesn’t mean we’re alone in the universe when it comes to intelligent life. Our detection tools are still quite primitive in comparison to something that harvests entire stars, and we also don’t have a great view of the entire universe. Additionally, due to the nature of how light travels across space, we’re seeing views of stars and galaxies that existed in that state ten, a hundred, hundreds of millions or even billions of years ago.

Stay curious, 7B.