The Kardashev Scale
A metre stick for civilisation
What metric would you use to measure the development of a civilization? This was the question that Nikolai Kardashev had pondered. Would population size work? Maybe age? But there was one metric that rose proportionately to the development of any civilization. That metric is energy usage. Using that metric, he devised a theoretical scale that could be used to approximate the technological advancement of any civilization. Essentially, the more energy a civilization could use, the more advanced it would be. This could even be applied to alien civilizations that humanity could come across in the far future.
What is the Kardashev scale?
The Kardashev scale is a theoretical scale that divides civilizations into categories based on how much energy they can use. The scale is divided into 4 separate groups (0, I, II, & III) and the categories are ranked starting from Type 0 to III where 0 represents the smallest civilisations and III represents the largest ones, with each of them representing an increasing order of magnitude in energy availability that can be harnessed by a civilization, measured by the total amount of power in watts (W). Allowing this scale to be used as both a measure of the development of human civilization and as an indicator of any others we might come across.
Why is energy used as the metric for this scale?
The amount of energy that a civilization could harness and utilize is an accurate way to tell how advanced they are, as an example, primitive humans could only harness the energy stored in food and utilize it with their muscles. This meant only a small amount of energy was harnessed throughout the entire population and as such, this primitivity was reflected in their technological development being delegated to simple stone tools. On the other hand, modern humans are able to acquire energy in various ways such as by burning fossil fuels, renewable wind and solar power and many more. We are then able to use that energy to develop and power a variety of world-changing technologies. As shown, the amount of energy we’re able to access rises directly with the level of development of humanity as a whole. This leads to energy being used as the main metric for this scale because technological development is directly correlated to the consumption of energy.
Where does humanity land in all of this?
Although the original scale was strictly divided into types, American astronomer Carl Sagan modified the scale by devising a formula to allow civilizations to fall between the main categories of the scale. While this formula is slightly too complex to be covered in this article, humanity would have a rating of 0.73 on this variation of the scale. If human energy consumption increases by the projected 3% a year, we might reach Type I status in the next 1-2 centuries (assuming we don’t wipe each other out first). Furthermore, we might even be able to reach Type II status in the next few thousand years too. This means that your children or grandchildren might be able to watch humanity as they progress into a whole different category of civilization.
What do the different categories represent?
Type 0: A Type 0 civilization would be a Subglobal civilization: One that would be able to harness energy from their home planet via more primitive means such as oil extraction or burning wood. In literal terms, a Type 0 is just any civilization that can’t harness all of the possible energy provided by its home planet as just used as an umbrella term for all civilizations falling below Type 1. A civilization of this type would most likely be unable to access any form of space propulsion apart from chemical rockets and ion thrusters. This would mean that they'd be effectively trapped on their home planet due to the abysmal speed of travel using these kinds of rockets when compared to the relative size of the star system they reside in.
Above: Diagram of a conventional chemical rocket motor.
Type I: Type I civilizations would be Planetary civilizations. Or civilizations with “A technological level close to the level presently attained on Earth,” as stated by Kardashev himself. These civilizations would be able to harness all of the energy available to their homeworld from their parent star. A Civilization like this could use methods such as the widespread utilization of an energy production method called nuclear fusion. Nuclear fusion is a process in which the nuclei of 2 lighter elements are slammed together at immense speeds forming the nucleus of a heavier element. This process will release energy because the mass of the heavier nucleus is less than the mass of the 2 lighter nuclei resulting in all of the leftover mass becoming energy. This mass to energy conversion is shown in Einstein's famous equation E=mc2 which shows that mass can be converted into energy and vice versa. In the case of humanity, acquiring fuel for this reaction would be fairly easy because one of the elements needed for the optimal fusion reaction, deuterium, can be found in massive quantities in our oceans. The other element, tritium, is unfortunately much rarer because the main way of acquiring it is as a byproduct of putting lithium into a nuclear reactor. Lithium itself is quite rare at the moment but if we gain the ability to extract it from our oceans then we would have more than enough fuel to get humanity to Type I and power it at that level for a further 10,000 years.
Methods of acquiring power such as solar, wind, geothermal, or hydroelectric would be much less feasible to allow a civilization to achieve Type I status. This is due to the fact that the structures needed to capture energy via these methods would require a vast amount of surface area on their home planet; this could potentially decimate the environment and cause a mass extinction. In the case of humanity, it is theorized that achieving Type I status using only surface based renewables would be impossible. This is because we would have to cover the entire planet with man-made structures, which would have devastating effects on the environment. A more feasible method would be to launch large solar panels into space, which could theoretically beam massive amounts of solar energy to earth as microwave radiation without taking up space on the surface. Unfortunately, all of these energy production methods have a drawback. This drawback is that they would massively heat up the planet and cause massive shifts in the climate throughout, this is due to the fact that all of these energy sources aren't 100% efficient meaning that while they produce immense amounts of energy, they also produce large amounts of waste heat.
Type II: Type II civilizations could use the same methods as Type I civilizations but on multiple planets in their star system. These civilizations are defined by their capability to harness almost all of the energy radiated from their own star and would likely have colonies all over their home system. To achieve this, they would probably also have the technology to allow them to travel between planets freely and without major strain on their resources. To achieve type II status, a civilization of high type I (eg. 1.8/1.9) could choose to use their vast amounts of resources to build hypothetical megastructures such as Dyson swarms* or other such constructions to capture the energy output of their entire star. This would cause them to reach type II.
*A Dyson swarm is a theoretical mega-structure that utilizes a swarm of power satellites (basically giant solar cells) to encompass a star. This would absorb a large portion of the energy that the star gives out and could power an entire system with ease.
Above: An artist's rendition of a theoretical Dyson swarm
Type III: A Type III civilization would span across every star system of a galaxy or multiple galaxies. As stated by Kardashev in his original paper, they would have access to “energy on the scale of its own galaxy.” The technology required to achieve a civilization of Type III and above would likely be incomprehensible to humanity and any attempt to come up with their power generation strategies would likely be science fiction rather than actual fact. Because of the vast scale that would be demonstrated in this type of civilization, the inhabitants of different regions of space would probably diverge into different species altogether after enough time. Unfortunately, (or maybe fortunately) studies on infrared ray emissions and satellite observations have led astronomers to the conclusion that it is extremely unlikely that any civilizations of Type III and above exist in the observable universe.
From alien civilizations to humanity itself, the Kardeshev scale proves to be useful in measuring the development of a race. The classifications of Type I to IV are great ways to provoke thoughts about potential technologies and are also great tools to educate people about what humanity itself is developing to progress along this imaginary scale.
Written by Anik Ratta
Additional credit to Nyra in 9F for helping with proofreading and editing.
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