Kardashev scale

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Kardashev scale projections for human civilization ranging from years 1900 to 2030, based on data from the International Energy Agency World Energy Outlook

The Kardashev scale is a method of measuring a civilization's level of technological advancement. The scale is only theoretical and in terms of an actual civilization highly speculative; however, it puts energy consumption of an entire civilization in a cosmic perspective. It was first proposed in 1964 by the Soviet Russian astronomer Nikolai Kardashev. The scale has three designated categories called Type I, II, and III. These are based on the amount of usable energy a civilization has at its disposal, and the degree of space colonization. In general terms, a Type I civilization has achieved mastery of the resources of its home planet, Type II of its solar system, and Type III of its galaxy.^[1]

[edit] Energy use

Energy is a static quantity and is denoted in joules. Power is a measure of energy transfer over time, and is denoted in watts (joules per second). The three levels of the Kardashev Scale can be quantified in units of power (watts) and plotted on an increasing logarithmic scale.

• Type I — a civilization that is able to harness all of the power available on a single planet — has approximately 10¹⁶ or 10¹⁷ W available.^[2] Earth specifically has an available power of 1.74  × 10¹⁷ W (174 petawatts, see Earth's energy budget). Kardashev's original definition was 4  × 10¹² W — a "technological level close to the level presently attained on earth" (presently meaning 1964).^[3]
• Type II — a civilization that is able to harness all of the power available from a single star, approximately 4  × 10²⁶ W.^[2] Again, this figure is variable; the Sun outputs approximately 3.86  × 10²⁶ W. Kardashev's original definition was also 4  × 10²⁶ W.^[3]
• Type III — a civilization that is able to harness all of the power available from a single galaxy, approximately 4  × 10³⁷ W.^[2] This figure is extremely variable, since galaxies vary widely in size; the stated figure is the approximate power output of the Milky Way. Kardashev's original definition was also 4  × 10³⁷ W.^[3]

Using nuclear explosion tests as a perspective, Tsar Bomba, the largest nuclear weapon ever detonated, released an estimated 57 megaton yield; even a Type I civilization makes use of roughly 25 megatons of TNT equivalent a second. A Type II civilization consumes 4 × 10⁹ times more energy (4 billion hydrogen bombs per second), and a type III 10¹¹ times more yet.

Current human civilization has a Kardashev value of about 0.7. However, the Kardashev scale was not developed to model a specific civilization. It's primarily used by SETI researchers, science fiction authors, and futurists as a theoretical framework.

[edit] Current status of human civilization

Human civilization is currently somewhere below Type I, as it is able to harness only a portion of the energy that is available on Earth. The current state of human civilization has thus been named Type 0. Although intermediate values were not discussed in Kardashev's original proposal, Carl Sagan argued that they could easily be defined by interpolating and extrapolating the values given above. In 1973, he calculated humanity's civilization type to be 0.7, in relationship to Kardashev's model for Types 0 and I.^[4]

Sagan used the formula:

Value K is a civilization's Kardashev rating and W is its power output in watts. Sagan used 10 TW as value W, which was considerably higher than present data suggests.^[5] Sagan's overestimation makes little difference in regards to human civilization's K rating, effecting only a difference of 1% in the value of K (See Table Below). International Energy Agency World Energy Outlook (2005)^[5] and section 7 of Key World Energy Statistics^[6] project values for planetary power production yielding these corresponding Kardashev scale estimates:

As of 2007, the Fractional Kardashev equivalent is approximately 0.72, calculated using BP's primary energy consumption chart for 2007.^[9]

[edit] Energy development

Methods by which a civilization could feasibly advance to Type I:

• Large scale application of fusion power. Type I implies the generation of about 5 kg of energy per second. This can be achieved by fusing about 1,000 kg of hydrogen into helium each second, a rate of about 3 × 10¹⁰ kg/year. A cubic km of water contains about 10¹¹ kg of hydrogen, and the Earth's oceans contain about 1.3 × 10⁹ cubic km of water. So this rate of production can be sustained over geological time scales.
• Anti-matter production is still beyond our civilization's ability to utilize as a power source,^[10] but any civilization with the technological ability to produce or collect anti-matter^[11] in large quantities cheaply, would have a mechanism to produce power on a scale several factors above our current level of technology. In antimatter-matter collisions, the entire rest mass of the particles is converted to kinetic energy. The energy per unit mass is about 10 orders of magnitude greater than chemical energy (compared to TNT), about 4 orders of magnitude greater than the energy that humans liberated today using nuclear fission, and about 2 orders of magnitude greater than the best possible from fusion.^[12] The reaction of 1 kg of anti-matter with 1 kg of matter would produce 1.8 × 10¹⁷ J (180 petajoules) of energy (by the mass-energy equivalence formula E = mc²), or roughly the equivalent of 47 megatons of TNT. For energy comparisons see anti-matter as a fuel source.
• Solar energy — converting sunlight into electricity by either solar cells or indirectly through wind and hydroelectric power. Currently, there is no known way for human civilization to successfully utilize the equivalent of the Earth's total absorbed solar energy without completely coating the surface with man-made structures, which is presently not feasible. However, if a civilization constructed very large space-based power satellites, Type I power levels might be achievable.

Figure of a Dyson swarm surrounding a star

Type II civilizations might employ:

• A Dyson sphere or Dyson swarm and similar constructs are hypothetical megastructures originally described by Freeman Dyson as a system of orbiting solar power satellites meant to completely enclose a star and capture most or all of its energy output.^[13]
• Perhaps a more exotic means to generate usable energy would be to feed a stellar mass into a black hole, and collect photons emitted by the accretion disc.^[14][15] Less exotic would be simply to capture photons already escaping from the accretion disc, reducing a black hole's angular momentum; known as the Penrose process.
• In sufficiently large number of stellar systems, absorbing a small but significant fraction of the output of each individual star.

Type III civilizations might use the same techniques employed by a Type II civilization, but applied to all of the stars of one or more galaxies individually.^[16] They may also be able to tap into the energy produced from a supermassive black hole which are believed to exist at the center of most galaxies.

Dr. Michio Kaku has discussed a type IV civilization, which could harness "extragalactic" energy sources such as dark energy, in his book Parallel Worlds.^[17]

[edit] Civilization implications

There are many historical examples of civilizations undergoing large-scale transitions, such as the Industrial Revolution. The transition between Kardashev scale levels could potentially represent similarly dramatic periods of social upheaval, since they entail surpassing the hard limits of the resources available in a civilization's existing territory. A common speculation^[18] suggests that the transition from Type 0 to Type I might carry a strong risk of self-destruction since there would no longer be room for further expansion on the civilization's home planet, similar to a Malthusian catastrophe. Excessive use of energy without adequate disposal of heat, for example, could make the planet of a civilization approaching Type I unsuitable to the biology of the dominant life-forms and their food sources. If Earth is an example, then sea temperatures in excess of 35 °C would jeopardize marine life and make the cooling of mammals to temperatures suitable for their metabolism difficult if not impossible. Of course, these theoretical speculations may not become problems in reality thanks to the application of future engineering and technology.

[edit] Extensions to the original scale

The sub-Type I state that human civilization currently occupies was not originally included in the Kardashev scale but is now referred to as "Type 0" or by its K value using Sagan's logarithmic formula (described above).

Zoltan Galantai has defined a further extrapolation of the scale, a Type IV level which controls the energy output of the visible universe; this is within a few orders of magnitude of 10⁴⁵ W. Such a civilization approaches or surpasses the limits of speculation based on current scientific understanding, and may not be possible. Frank J. Tipler's Omega point would presumably occupy this level, as would the Biocosm hypothesis. Galantai has argued that such a civilization could not be detected, as its activities would be indistinguishable from the workings of nature (there being nothing to compare them to).^[19]

However, Milan M. Ćirković has argued that "Type IV" should instead be used to refer to a civilization that has harnessed the power of its supercluster, or "the largest gravitationally bound structure it originated in".^[20] For the Local Supercluster, this would be approximately 10⁴² W.

In contrast to simply increasing the maximum power level covered by the scale, Carl Sagan suggested adding another dimension: the information available to the civilization. He assigned the letter A to represent 10⁶ unique bits of information (less than any recorded human culture) and each successive letter to represent an order of magnitude increase, so that a level Z civilization would have 10³¹ bits. In this classification, 1973 Earth is a 0.7 H civilization, with access to 10¹³ bits of information. Sagan believed that no civilization has yet reached level Z, conjecturing that so much unique information would exceed that of all the intelligent species in a galactic supercluster and observing that the universe is not old enough to effectively exchange information over larger distances. The information and energy axes are independent, so that even a level Z civilization would not need to be Kardeshev Type III.^[4]

[edit] Criticism

It has been argued that, because we cannot understand advanced civilizations, we cannot predict their behavior; thus, Kardashev's visualization may not reflect what will actually occur for an advanced civilization. This central argument is found within the book Evolving the Alien: The Science of Extraterrestrial Life.^[21]

[edit] See also

Sustainable development portal

• Astroengineering
• Clarke's three laws
• Drake equation
• World energy resources and consumption
• Orders of magnitude (power)
• Orders of magnitude (energy)

[edit] References

[edit] Further reading

[edit] External links

• Kardashev civilizations
• Detectability of Extraterrestrial Technological Activities
• Flash Animation on Civilizations
• After Kardashev: Farewell to Super Civilizations
• Exotic Civilizations: Beyond Kardashev
• Useful Comparisons of Fictional Works Using the Kardashev Scale
• Using world history to predict the future (based on patterns in five epochs of civilization)