Kardashev scale

The Kardashev scale (Russian: шкала Кардашёва, romanized: shkala Kardashyova) is a method of measuring a civilization's level of technological advancement based on the amount of energy it is capable of harnessing and using.

[1][9] A civilization known as "Type I" has achieved a technological level close to the one attained on earth at the time Kardashev’s article was submitted (December 1963), with a rate of energy consumption evaluated at about 4 x 1012 watts (W).

A civilization known as "Type II" would surpass the first by fourteen orders of magnitude, matching the entire power emitted by the Sun in about 3,200 years, i.e, our home star’s “output“ at that time, predicted at 4 × 1026 W. Finally, a civilization known as "Type III" reaches the milepost set in 5,800 years when humanity’s rate of energy consumption is predicted by the author to match the power emitted by the approximated 1011 stars in our home galaxy, the Milky Way, which involves harnessing power of up to an estimated 4 x 1037 W.[1] Assuming the development of radio, Kardashev predicted that in the following two decades (i.e. in the 1980s) it would be possible to build antennas of 100,000 m2 capable of detecting Type II and III civilizations.

The most suitable region of the galaxy for observing Type II and III civilizations would then be the Galactic Center, due to the high density of the stellar population it harbors.

On the other hand, since our present development covers only a negligible fraction of this communication phase, Kardashev hypothesized the high improbability that we will meet "brothers in intelligence" who are at the same stage of evolution as are we.

Kardashev believed that the search should focus on the millimeter wavelength spectrum, close to the maximum intensity of the cosmic microwave background, rather than in the 21-centimeter band (which is the domain of investigation of the SETI program).

According to Kardashev, in order to capture the significant radiation of an advanced civilization emitted by a megastructure (such as a Dyson sphere), a radio telescope with a diameter larger than that of the Earth would have to be placed in orbital space.

[4] Kardashev concluded by predicting that the search for extraterrestrial civilizations would lead to positive results in the [then] next decade, giving humanity access to a vast amount of information about the Universe and its evolution over a period of several billion years.

The Soviet astronomer reminds us that we search for these supercivilizations on the basis of our own development criteria, and that predictions are possible only for extraterrestrial worlds close to our technological level, the others being beyond our intellectual representation.

[6] According to Kardashev, it is essential to focus our search tools on new objects radiating at a wavelength of a few microns to a few millimeters, and at a temperature of 3 to 300 K, which is characteristic of large structures of solid matter.

The astronomer Guillermo A. Lemarchand defined Type I as a level close to today's terrestrial civilization, with an energy capacity equivalent to Earth's solar irradiance, between 1016 and 1017 watts.

By studying the evolution of technologies that have changed history (paper, the integrated circuit), Kaku believes that humanity is moving toward a civilization of planetary dimensions, the "starting point" of which is the Internet.

If these areas do not develop, Kaku predicts that humanity will sink into the "abyss":[32] an advanced civilization must grow faster than the frequency of occurrence of extinction-level cosmic catastrophes, such as comet or asteroid impacts.

[36] Zoltan Galántai recognizes the important role that Kardashev's classification has played in the SETI program, but he believes that another scale is possible, without using energy consumption, by resorting to miniaturization.

Finally, the Kardashev scale is the product of an era of insufficient scientific knowledge, which considered the possibility of stellar object CTA-102 as an artificial Type III source, whereas today we know that it is a galactic nucleus.

Robotics is the only way to access so many dispersed resources, and humanity should embark on a second long-term project, which Metzger calls the "robotsphere", that would begin with the energetic exploitation of the Moon (estimated at 2.3 × 1013 J/year).

[40] Viorel Badescu and Richard B. Cathcart have studied the possibility that a Type II civilization could use a 450 million kilometer device to direct solar radiation and thus be able to impart a kinetic motion to its star that deviates it from its usual trajectory by about 35 to 40 parsecs,[41] allowing it, among other things, to capture its energy and navigate the galaxy.

[45] According to Kardashev, the most important parameters to define the existence of a civilization are three: the presence of very powerful energy sources, the use of non-standard technologies, and the transmission of significant amounts of information of various kinds through space.

[46] Kardashev's classification is based on the hypothesis that an advanced civilization uses significant energy, which implies that it must be de facto detectable over long distances, as summarized by Zoltan Galántai.

[48] Astrophysicist Makoto Inoue and economist Hiromitsu Yokoo have explored the possibility that a Type III civilization could extract energy from a supermassive black hole (SMBH).

The search for material traces of such civilizations (e.g. Dyson spheres or stellar engines), an "interesting alternative" to the conventional SETI program, lays the foundation for a "cosmic archaeology" according to Richard A. Carrigan.

Efforts to detect intelligence markers in the atmospheres of exoplanets (such as freon, oxygen, or even ozone, residues of biotic activity according to James Lovelock's research)[24] are one of the most promising avenues.

[58] For Kardashev, "in the next 5 to 10 years, all the sources of radiation with the largest observable flux, in all the regions of the electromagnetic spectrum, will have been discovered and studied", the sensitivity of the listening devices having indeed reached their technical limits.

Zoltan Galántai explains that "it is impossible to calculate the future of the Universe over long periods of time without including the effects of life and intelligence", a position close to that of Freeman Dyson.

[64] In 1963, Nikolai Kardashev and Gennady Borissovich Sholomitskii studied the CTA 102 radio source on the 920 MHz band from the Crimea Deep Space Station, looking for signs of a Type III civilization.

[71] In 1976, Kardashev, Troitskii, and Gindilis used the RATAN-600 radio telescope in the North Caucasus to search for signals from Type II or III civilizations in the Milky Way and other nearby galaxies.

However, because of the possibility that planetary systems are much older than our own, and considering that cosmic objects such as quasars could be products of supercivilization activity, a detailed program of listening and searching for intelligent signs remains valid.

This program includes:[46] According to Kardashev, only a radio interferometer with a base, either of the order of or larger than the diameter of the Earth, placed in orbital space, would allow listening to centimetric and decimetric frequencies.

The transitions between Kardashev scale levels could potentially represent similarly dramatic periods of social upheaval, as they involve exceeding the hard limits of the resources available within a civilization's existing territory.

For example, excessive energy consumption without adequate heat removal could plausibly render the planet of a Type I approaching civilization unsuitable for the biology of the dominant life forms and their food sources.

In the foreground, an astronomical observatory emits a ray of light vertically. In the background is a cluster of stars in the night.
At the Cerro Paranal Observatory , a laser beam is used to create an artificial star to tune the Very Large Telescope (VLT). The search for exoplanets on which extraterrestrial civilizations could be found is one of the many missions of the VLT.
A red dotted line that goes up from left to right.
Projection of the Kardashev scale to 2040 based on data from the International Energy Agency World Energy Outlook
Three schematic representations: Earth, Solar System and Milky Way
Energy consumption in three types of civilization as defined by Sagan's extended Kardashev scale
A broken line in blue goes, from left to right, from the bottom to the top
Graph of world primary energy consumption in 2011 according to the BP Statistical Review
Color illustration. An object resembling a truncated trumpet has white spots on its surface.
According to the standard model describing the expansion of the Universe since the Big Bang , there may be planets older than the Earth, capable of harboring supercivilizations.
Color illustration. A burning object pierces the surface of a much larger object.
For Zoltan Galántai, a scale classifying civilizations should be based on their ability to survive catastrophes, particularly those of cosmic origin, such as an asteroid impact .
Color illustration. A yellow-orange disc in the center is pierced vertically by a spiral of filaments.
Artist's view of quasar GB1508. According to Russian astronomer Kardashev, a highly evolved civilization, known as "Type III" in his theoretical classification, would be able to draw its energy from such a source.
Color illustration. Geometric shapes in various colors are drawn on a black background.
Screenshot of the SETI@home computer program
On a black background, a round luminous glow.
Galaxy M87 has an active galactic nucleus , providing a strong source of radiation in all wavelengths . This type of radiation was considered by Kardashev to be one of the possible signals of an advanced civilization.
Color photo. A luminous celestial object appears against a black background.
Quasar 3C 273 , the brightest ever observed
Figure of a Dyson swarm surrounding a star