While there is currently no concrete evidence to suggest the existence of extraterrestrial civilizations, humans have nevertheless begun to develop protocols aimed at managing detection and potential first contact with one of them. Called "post-detection protocols" (PDD), these sets of rules and guidelines aim to frame the response of policies and institutions to such an event.
According to the scientific collaboration SETI (Search for Extra-Terrestrial Intelligence ), the role of post-detection protocols is to constitute a set of rules and guidelines regarding "detection, analysis and response to signals or messages whose origin is confirmed to be an extraterrestrial civilization. Currently, while no PPD has been formally adopted by government agencies, members of the UN have incorporated some of these recommendations.
However, the scientific community is working to develop rapid and coherent action plans, the most successful of which is the "Statement of principles relating to activities after the detection of extraterrestrial intelligence ". The latter was developed by the International Academy of Astronautics (IAA, an NGO bringing together several universities, laboratories and technological centers) in collaboration with the SETI program, the International Astronautical Federation and the International Institute of Space Law. In 1992, it was officially adopted by the International Committee for Space Research and by the International Astronomical Union. This statement was also sent to all UN member governments, as well as various NGOs.
Other draft PPDs were also developed. In 1960, NASA commissioned a report from the Brookings Institution (a group of American scientists reflecting on social, economic, political and ethical issues) concerning human activities in space. Titled "Proposed Studies on the Implications of Peaceful Space Activities for Human Affairs the Brookings Report contains a section titled "Implications of the Discovery of Extraterrestrial Life", offering several post-detection scenarios for governments and the circumstances under which such information should, or should not, be released to the public.
As a general rule, PPDs are based on theoretical and experimental research carried out by the SETI, Active SETI (or METI for Messaging to Extra-Terrestrial Intelligence) projects. ) and CETI (Communication with ExtraTerrestrial Intelligence ). This research does not concern the discovery of non-intelligent extraterrestrial life (unicellular, microbial, plant, etc.) whose aspects fall more specifically into astrobiology and planetary protection/contamination. They are more oriented towards the detection and analysis of radioelectric signals (low-energy electromagnetic waves), which are classically the technosignature of a civilization mastering communication systems.
In 1990, physicist, engineer and sociologist Zbigniew Paprotny (Polish Astronautical Society) published an article in the journal Acta Astronautica titled "Signals from ETI detected — What next? in which he makes several suggestions regarding the handling of the detection of an extraterrestrial civilization. It highlights three factors, which today constitute the pillar around which PPDs revolve. First, the ability of governments and populations to accept the news of the detection of an ET civilization. Second, how this news is made public and relayed. Third, the intelligibility of the message contained in the signal.
In order to best manage detection or contact with an extraterrestrial civilization, it is crucial to be able to gauge the importance of the signals and transmissions received. The evaluation of a signal is essential, because it directly conditions the actions to be taken. To do this, scientists have developed two scales to quantify and qualify the importance of potential communications between the Earth and an ET intelligence.
The first to be developed is the Rio scale, proposed by astronomers Iván Almár and Jill Tarter to guide public policy in choosing an appropriate initial response, and in assessing the consequences of a potential detection. . Officially adopted by the SETI Permanent Study Group (PSG) at the IAA, this scale—which is based on the Turin scale used to assess the threat of near-Earth asteroids—has a dual purpose:to frame detection claims of an extraterrestrial civilization and prevent false positives, the consequences of which could be disastrous. The scale goes from 0 to 10.
The second scale, proposed in 2005 by Iván Almár, is the San Marino scale. Unlike the Rio scale, it makes it possible to quantify the risk linked to voluntary transmissions from Earth; transmissions that could be picked up and responded to. It takes into account the intensity of the signal and the message it contains. It was officially adopted by the SETI PSG in September 2007. The San Marino scale ranges from 1 to 10.
Beyond the qualification of the signal and its importance, other parameters come into play in the development of an effective PPD. This is particularly the case of the type and nature of the form of life discovered (morphology, organization), the presence or not of a particular and decipherable language, the localization of the signal, the content of the message and its involvement, as well as the open-mindedness of human societies. Thus, depending on these variables, a wide variety of scenarios must be planned, correlated with controlled communication strategies.
The role of a PPD is also to predict and adapt to the socio-cultural consequences of a confirmed ET detection. The press, religions, populations, governments and the scientific community are all actors whose reactions are variable and generally differ from each other. It is therefore crucial to undertake comparative socio-cultural studies and to aggregate all possible metadata concerning established behavioral patterns, historical reactions and religious disparities, in order to be able to quickly deliver appropriate public information.
One of the solutions proposed during the international colloquium on the social implications of astrobiology in 1999, would be to explore the capacity of religions to "constitute a resource allowing to absorb the impact of such a discovery and to maintain beneficial relations with civilization detected”.
A PPD must also consider the political motivations of government bodies, and predict how political organizations might use the news of ET intelligence detection to their advantage. The consequences of this news could be minimized or accentuated, presented as beneficial for the human species or, on the contrary, as dangerous and requiring distrust.
The PPD must also regulate the communication of the news, and the speed at which it is transmitted. In addition, any PPD must question the merits of communicating too quickly. As a general rule, it is accepted that if the content of the message received is ambiguous or complex to decipher, the information must be withheld until the ambiguity is resolved or the message is, at least partially, decrypted. .
A PPD must also manage the situation where the discovery would be made by a government entity which would refuse to share the information, a situation which would cause an international political conflict, all the more so if the entity in question is the only one to possess the technology to communicate with the ET civilization.
One of the important aspects to consider is the opportunity of a response from Earth as well as the content of this potential response. This aspect of the PPD draws heavily on research conducted by CETI, which is dedicated to studying and developing ways and plans to respond to ET intelligence.
In the event that the message received is intelligible to us, the first step would be to remove any possible ambiguity, in order to ensure that the content of the message has been correctly understood and apprehended. The second step would then be to define the means by which the response would be sent, as well as the content of this response. In addition, if this response can be transmitted by several actors, should it be collective or be at the discretion of each?
The response sent must also be clear and unambiguous. It must be explicit and easily understood by a civilization having neither written nor oral language. Several scientists have proposed mathematical, algorithmic, pictorial or symbolic languages. In any case, the content of the message must be universal and simple enough to be understood. Considering that the development of an international collective response could be extremely long, each DPL must provide common guidelines on the conduct to be followed in the event of the formulation of a response.
Finally, a PPD must consider the implications of the existence of technological disparities between Earth and an extraterrestrial civilization. First of all, it is possible that a significant technological difference exists between our astronomical communications instruments, conditioning the quality and integrity of the messages exchanged. In addition, this technological difference can also exist at the level of armament. In this case, it would then be potentially dangerous to reveal to an ET intelligence the exact coordinates of the Earth, especially if its intentions are not clearly perceptible.
