In 1950, over lunch with colleagues at Los Alamos National Laboratory, physicist Enrico Fermi asked a question that stuck: “Where is everybody?” More than seventy years on, nobody has answered it. Universe Today’s long-running “Beyond Fermi’s Paradox” series ends with a different question, which it ranks alongside Fermi’s and “Are we alone in the Universe?” What happens if contact actually comes?
The author’s view is that the Fermi Paradox needs solving only once. One piece of unambiguous evidence of extraterrestrial intelligence would settle it for good.
Awe and dread
Reactions split fast. Some people picture an advanced, enlightened species arriving to help humanity sort out its problems. Others picture “War of the Worlds,” with hostile visitors knocking down buildings and taking what they want. The series notes that contact could bring technology and cultural exchange, and also exposure to viruses, whether computerized or biological, plus infiltration, subterfuge and attack. Imperialism and colonialism, it says, make the risk hard to dismiss.
Whatever happens, the series calls confirmation that we are not alone the greatest discovery in human history. How people would take the news is another matter. Pandemonium, elation and war mobilization all get a mention.
Scales for a signal
Scientists have not left this entirely to speculation. They have built ranking scales, much as Kardashev and Barrow did for the technology of alien civilizations.
The Rio Scale came first. Hungarian astronomer Iván Almár and SETI pioneer Jill Tarter presented it at the 51st International Astronautical Conference in Rio de Janeiro in October 2000. Almár was then Deputy Director of the Konkoly Observatory, and Tarter was Chair Emeritus for SETI Research at the SETI Institute. By 2002 the International Academy of Astronautics (IAA) SETI Permanent Committee had adopted it.
Its job is to help policy-makers judge, from 0 to 10, how likely it is that a radio signal came from an extraterrestrial civilization. The model was the Torino Scale for near-Earth asteroid impacts. Almár and Tarter argued that announcing the discovery of extraterrestrial intelligence would carry social consequences like those of announcing an impending impact.
A 2011 revision added whether contact arrived as an interstellar message or a physical artifact, along with other signs of technological activity. Version 2.0 followed in 2018, with colleagues from several universities and research institutes, Breakthrough Listen among them. Its stated aims include a shared classification scheme across disciplines and a way to calibrate public expectations when signals reach the media.
Messages sent out from Earth have their own scale. Almár and H. Paul Shuch of The SETI League proposed the San Marino Scale in 2005, at an IAA conference in San Marino, Italy. The IAA’s SETI Permanent Study Group adopted it at its 2007 meeting in Hyderabad, India. Almár wrote that transmitting messages “remains a controversial area.” Some argue a civilization hoping to hear others is obliged to reveal itself. Others hold that “it is suicidal to shout in the jungle.”
The index adds two terms. One measures signal intensity against our Sun’s background radiation in the same band. The other rates the content of the transmission from 1, a randomly directed pulse, to 5, a deliberate reply to an extraterrestrial signal.
Who is listening
The series raises the possibility of malevolent or paranoid civilizations that treat any other intelligent life as a threat. Travel between stars takes so much time and energy that a fleet might arrive technologically behind. Malware broadcast as a greeting is another possibility. That scenario echoes Liu Cixin’s “The Three-Body Problem” and a paper by Michael Hippke of the Sonneberg Observatory and John G. Learned of the University of Hawaii, Manoa. Their paper, “Interstellar Communication. IX. Message Decontamination is Impossible,” argues that a complex message cannot be made safe with certainty and should be destroyed.
“Contact Optimists” see it differently. Most of our own signals are not aimed at anyone, they point out, and the messages scientists have deliberately sent, the Arecibo Message the best known, were technology demonstrations meant to announce our presence and perhaps our willingness to talk. Under the Copernican Principle, other civilizations might share that curiosity. Carl Sagan warned against assuming everyone wants the same thing, and David Brin wrote in “The Great Silence” that a single exception is enough to break the rule.
