Editing Kardashev scale (section)

==== Possible scenarios for the evolution of supercivilizations ====
{{See also|Potential cultural impact of extraterrestrial contact}}
Kardashev believes that it is very likely that a supercivilization has already detected and observed humanity through cosmic-sized telescopes. He discusses this in a 1997 article on the subject, entitled ''Radioastron – a Radio Telescope Much Greater than the Earth''.<ref name="Kardashev-1997-2">{{Cite journal |last=Kardashev |first=Nikolai S. |date=1997-12-01 |title=Radioastron – a Radio Telescope Much Greater than the Earth |url=https://doi.org/10.1023/A:1007937203880 |journal=Experimental Astronomy |language=en |volume=7 |issue=4 |pages=329–343 |doi=10.1023/A:1007937203880 |bibcode=1997ExA.....7..329K |issn=1572-9508 |s2cid=118639223}}</ref> For this supercivilization, the science of "cosmic ethnography" must be highly developed. However, the fact that [[Fermi paradox|no contact has been made so far]] could be explained by [[Zoo hypothesis|ethical considerations of these civilizations]]. Based on this principle, Kardashev sees only two possible evolutionary scenarios for a supercivilization: natural evolution and [[Potential cultural impact of extraterrestrial contact|evolution after contact with other extraterrestrial civilizations]]. He considers more likely the scenario based on contact between two civilizations highly developed technologically and culturally advanced civilizations; this scenario, which he calls the "Urbanization Hypothesis", would result in the regrouping and unification of several civilizations within a few compact regions of the [[Universe]].<ref name=Kardashev1985 />

Kardashev lists, in the form of investigative tools, six possible scenarios (summarized in a table at the end of his 1997 article)<ref name="Kardashev-1997-2" /> that explain the evolution of a civilization. Each of the scenarios corresponds to a [[probability]], one or more objects to be observed, an adapted procedure, and, finally the possible consequences for our civilization:<ref name=Kardashev1985 />

# The scenario of a large unification of civilizations over an extent of one to ten billion light-years with concentration in a certain region has a probability of 60%. These civilizations are to be searched for in the most powerful [[quasar]]s and in the [[galactic bulge]], at a radiation level higher than 10<sup>38</sup> watts, in the wavelengths from 10 μm to 1&nbsp;cm, as well as in the other regions of the spectrum. This is to detect megastructures or signals with a wavelength of 1.5&nbsp;mm<ref>{{Cite journal |last=Kardashev |first=Nikolai S. |date=1979 |title=Optimal wavelength region for communication with extraterrestrial intelligence: λ = 1.5 mm |url=https://www.nature.com/articles/278028a0 |journal=Nature |language=en |volume=278 |issue=5699 |pages=28–30 |bibcode=1979Natur.278...28K |doi=10.1038/278028a0 |issn=1476-4687 |s2cid=4341965}}</ref> and omnidirectional emission up to 21&nbsp;cm. In the event of contact, humanity would see progress in all areas of society in order to join this supercivilization; it is also expected that an [[Ethnography|ethnographic]] conservatory would be created on Earth.
# The scenario of a unification on the scale of the [[Open cluster|galactic cluster]] has only a 20% probability of realization. Kardashev advises to observe the [[Virgo Cluster|Virgo cluster]] (especially [[Messier 87|M87]]) and other clusters in a similar way as in the first scenario. The consequences for humanity are the same as in the first scenario.
# The scenario of a unification on the scale of galaxies has only a 10% probability. To confirm it, we must study the galactic centers, both of the [[Milky Way]] and of neighboring galaxies (such as [[Andromeda Galaxy|M31]], [[Triangulum Galaxy|M33]]), according to a procedure similar to that of the first scenario. The consequences for humanity are the same as in the first scenario.
# The scenario of a complete [[Space colonization|colonization of space]] has no probability of being realized according to Kardashev because if it were realizable then "they" would already be on Earth; yet this is not the case. However, in the case of a contact, the consequences on humanity are the same as in the first scenario.
# This scenario assumes that all civilizations would have destroyed themselves before any contact. Kardashev estimates the probability of this to be 10%. Humanity should be able to detect ancient megastructures in the vicinity of the [[List of nearest stars and brown dwarfs|nearest stars]]. As a result, no contact with humanity can take place.
# The last scenario suggests that we are the first or the only ones in the Universe. Kardashev estimates its probability at 10%. Only [[Astrobiology|exobiology]] can confirm or falsify such a scenario. We can imagine a potential [[First contact (science fiction)|contact]] in the distant future, and then the consequences would be similar to those of the other five scenarios.