Last month I attended (virtually) a scientific workshop on “technosignatures,” held in Houston and sponsored by NASA. It was weird, fascinating, and ultimately frustrating.
NASA sponsored this workshop, organized by scientists with the Nexus for Exoplanet System Science (NExSS), because Rep. Lamar Smith (R-TX), chairman of the House Science Committee, which is in charge of authorizing NASA programs, is fascinated by SETI and thinks NASA should get back in the game. Rep. Smith, by means of a video clip, opened the workshop by saying he’s read every single book on the subject.
Michael New, the NASA Science Mission Directorate’s deputy associate administrator for research, said at the workshop that NASA was sponsoring the meeting because “there’s language in our authorization bill that says we should be interested.” New also mentioned that NASA’s call for proposals for exobiology research does not exclude SETI research in general – only searches for radio signals of extraterrestrial intelligent origin.
Scientists engaged in the search for evidence of extraterrestrial intelligent life (SETI, for search for extraterrestrial intelligence) have decided that “SETI” has acquired a taint. So now they say they are searching for evidence of technosignatures – that is, evidence of technologies produced by intelligent life. It’s still SETI, as far as I’m concerned (see below for more on what a technosignature might be).
Scientists at the workshop offered up many interesting, intriguing, far-out, and to a large degree infeasible (either financially or technologically, though mostly financially) proposals for advancing the search for evidence of ETI life.
Sofia Sheikh of Penn State University reported to the group on recommendations from an ad hoc committee on “SETI nomenclature.” For example, the recommended definition for (or meaning of) “intelligence” is “the quality of being able to deliberately engineer technology which might be detectable using astronomical observation techniques.” (This definition excludes non-human varieties of intelligence – say, octopus intelligence, bird intelligence…). The group also recommends rejecting use of the term “advanced” because it’s a vague term that stems from “deprecated theories” (that is, the belief that human life is the pinnacle of evolution and that human life is superior to all other forms of life on Earth).
Nonetheless, other presenters referred to the so-called “Kardashev scale” – proposed in 1964 by Russian radio astronomer and SETI advocate Nikolai Kardashev – “ a method of measuring a civilization’s level of technological advancement based on the amount of energy a civilization is able to use,” according to Wikipedia.
David Grinspoon of the Planetary Science Institute questioned the wisdom of the Kardashev scale. The history of human civilizations “disqualifies us from considering ourselves an intelligent” species. So in pursuing SETI, “what we seek is not what we are.” An “inevitable-expansion fallacy” is embedded in the Kardashev scale, an assumption that the more energy a civilization consumes, the more developed it will be. Intelligent civilizations on Earth have not acted very intelligently.
Adam Frank of Rochester University posed the question, “How do we avoid anthropocentric tunnel-vision?” (Good question. It was on display in a number of presentations at the workshop. See below.)
SETI Institute president Bill Diamond claimed that “all of humanity is curious” about extraterrestrial intelligent life. (I myself am not aware of any convincing evidence showing this to be the case.) Diamond also claimed that “SETI can only serve to drive greater public interest” in space exploration and that SETI “can enhance NASA’s brand.” (These are questionable claims, and I disagree.)
Shubham Kanodia of Penn State noted that our knowledge of the “known” universe is severely lacking and that SETI scientists have searched very little of the “cosmic haystack” for evidence of ETI – “a bathtub of water out of all of Earth’s oceans.” Why? “Because we haven’t searched that much.” (Though this was not Kanodia’s point, the point to me is that the search space is so vast that the idea of a thorough search is implausible.)
Others argued that SETI researchers should be looking for evidence of non-terrestrial artifacts in our own solar system – say, on Mars or Venus, planets that may have been habitable billions of years ago. Ravi Kopparapu of Penn State said researchers have searched very little of the searchable space in the solar system, “Repeated searches with time” may yield finds. He also said what’s needed to advance the search for ETI artifacts is “further synthesis and study on the persistence of uniquely industrial byproducts in ocean sediment environments.”
Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, said we could explore the subsurface of Venus and Mars with ground-penetrating radar and deep drilling to look for buried signs of past civilizations. Such searches should look for metals, multiple extinction horizons, nuclear waste, plastics, and synthetic chemicals, for example. Something to think about: “What will the fingerprint of the Anthropocene era” – the current human-dominated era of life on Earth – “be in the eventual sedimentary record hundreds of millions of years from now? Fingerprints of past industry may be more apparent in geology than in artifacts, he said.
(These arguments for searching for ETI artifacts are based on the “anthropocentric-tunnel-vision” assumption that ET intelligence would be like human intelligence – not, say, octopus intelligence.)
It’s easy to design an algorithm to look for a specific hypothesized signal, noted David Kipping of Columbia University, but the challenge is knowing how to recognize “the truly weird.”
Other presenters offered ideas about how to employ data mining, machine learning, artificial intelligence, near-infrared/infrared astronomical observations.
Jamie Drew, chief of staff for the billionaire-backed Breakthrough Initiatives, reported on partners in the organization’s SETI project, Breakthrough Listen, including the Green Bank Observatory, the University of California-Berkeley, and the Square Kilometer Array. The project is also pursuing a partnership with China’s FAST 500 Telescope, now the largest radio telescope in the world. Drew also noted that Breakthrough will not be proceeding with its proposed Breakthrough Message project due to its controversial nature (many scientists think it would be unwise, perhaps unethical, to send messages out in hopes that they would be received by ETI).
It seems to me that the SETI community has done a good enough job of tapping into billionaire reserves (Paul Allen for the Allen Telescope Array, Yuri Milner for Breakthrough Listen). NASA receives far more qualified proposals for funding for astrophysics and planetary science research than it has the budget to fund. Why add SETI? And even if Rep. Smith’s proposed $10 million a year for two years for SETI at NASA is appropriated – an unknown right now – I can’t see how the sorts of science projects discussed at the workshop will get very far along. Then again, I’m a self-described SETI skeptic.