More on “technosignatures” (a.k.a. SETI)


Credit: YouTube

I’m just now reading the November 2018 report on the technosignatures workshop hosted by NASA in Houston, Texas, in September 2018. (I attended much of this workshop via livestreaming.) “Technosignatures” is the label that advocates for the search for extraterrestrial intelligence (SETI) have adopted in recent years to replace “SETI” – part of the community’s ongoing effort to further legitimize their work as “science” (and because it’s a long word, I’m going to shorten it to TSs here.) As I’ve said before, the search for TSs is still SETI.

SETI advocate Adam Frank said at the workshop that work going on today is “not your grandmother’s SETI” – that is, listening for radio signals from intelligent extraterrestrial life. SETI today involves consideration of radio, optical/near-infrared laser, atmospheric, structural and planet-scale signals (or signatures).

Nonetheless, SETI today continues to proceed on a pile of assumptions. (See below for a recap.)

Now-retired Rep. Lamar Smith (R-TX), who chaired the House Science, Space, and Technology Committee from January 3, 2013 to January 3, 2019, is a self-described SETI fan. In 2017, Smith advised NASA that it should be funding the search for TSs and said his committee would be authorizing $10 million for NASA TS research in 2018-2019 (fiscal year 2019). Responding to Smith’s direction, NASA hosted the September workshop, organized by the scientific community, to gather information on the state of the art of TS search.

I found the workshop report to be, first, a strongly worded advocacy document for federal funding of TS research, and, second, a review of the state of the art in TS research.

(Note: While the funding was authorized, NASA’s fiscal year 2019 appropriations did not include the $10 million for TS research.)

Michael New, deputy associate administrator for research in NASA’s Science Mission Directorate, said at the workshop that it was taking place because “there’s language in our authorization bill that says we should be interested” in TSs. Over the past 20 years, he noted, the astrobiology community has been developing a framework for identifying and exploring for biosignatures. TSs are a subset of this larger framework, he said. New also noted that NASA’s current call for exobiology research proposals includes TS research, excluding searches for radio signals.

(Note: New has advised me that NASA has modified language in its exobiology and astrophysics data analysis program calls for proposals to clarify the types of TS proposals these research and analysis programs are willing to consider. Again, the additional $10 million authorized for TS research was not appropriated, so proposals for TS research must compete with other proposals for funding.)

At NASA headquarters, the view as far as I understand it is that TS research is more within the purview of astrophysics than it is within astrobiology. Nonetheless, the workshop report – edited by SETI scientist Jason Wright and exoplanet researcher Dawn Gelino – states: “Technosignatures are analogous to biosignatures in that they are a detectable sign of extant or extinct life…. [W]hile some consider technosignatures to be a subset of biosignatures and others think of them as being complementary to biosignatures, either way searches for technosignatures are logically continuous with the search for biosignatures as part of astrobiology.”

In an introduction to the workshop report, Jason Wright wrote:

“As with biosignatures, one must proceed by hypothesizing a class of detectable technosignatures, motivated by life on Earth, and then designing a search for that technosignature considering both its detectability and its uniqueness. The search for technosignatures is thus broad, encompassing much of astronomy. Unlike biosignatures, many proposed technosignatures are self-luminous or involve the manipulation of energy from bright natural sources. Also, since technological life might spread through the galaxy, its technosignatures might be found far in both space and time from its point of abiogenesis. Compared to biosignatures, technosignatures might therefore be more ubiquitous, more obvious, more unambiguous, and detectable at much greater (even extragalactic) distances.”

I question this statement. Wright says, “many proposed technosignatures are self-luminous or involve the manipulation of energy from bright natural sources.” IMHO, it would be more accurate to say that “we believe that many of the technosignatures we propose to look for would be self-luminous or involve the manipulation of bright natural sources.” I also question the claim that “compared to biosignatures, technosignatures might…be more ubiquitous” etc. etc. This claim is speculative – based largely on assumptions, not knowledge.

The workshop report speculates about interstellar visitors to our solar system or past, extinct, technological cultures on Earth – speculations that I find far-fetched. “Because our exploration of the solar system remains so incomplete…it remains a potential search space for technosignatures. Most obvious is the investigation of hypothetical interstellar probes…. Because the geological, paleontological, and archaeological records on Earth are so incomplete, it is even possible that the Earth itself hosts such artifacts…. If technosignatures were discovered in the solar system, it would be worth considering whether their origin might not be interstellar. Specifically, since the Earth is home to the only known species capable of interstellar communication and planetary travel (although both technologies remain in their early development), the Earth remains the only known planet fecund enough to promote technological life, and so it or an early, habitable Mars or Venus could even be the origin  of such technology…. [P]revious episodes of widespread, planet-altering technology on the Earth by putative, now-extinct species (that existed long before humans did) might be identified through paleoclimate investigations using isotopic proxies, land-use analysis, transuranic elements (or fission byproducts), or by searching for artifacts in the geologic record..”


The report also suggests that the Library of Congress Blumberg Chair in Astrobiology program could provide an opportunity to fund a scholar who wants to study SETI. This program, intended to foster “research at the intersection of the science of astrobiology and its humanistic and societal implications,” could “overlap into technosignatures…. [R]esearch and events produced do not necessarily filter deeply into the science community. There may be ways to amplify the extent and impact of this program for both biosignatures and technosignatures.”

I’m quite familiar with this program and all of its chairs, and I doubt this will happen. (Just FYI, I will be moderating a free public program at the University of Washington on June 25 featuring three Blumberg chairs who will discuss their work at the Library of Congress.)

As to the “social dimensions and implications” of TS research, the report notes that “a recent significant public consultationprocess was undertaken by NASA in collaboration with researchers from Arizona State University’sConsortium for Science, Policy, and Outcomes.” This public consultation project was conducted in connection with a then-high-priority project at NASA, the Asteroid Initiative. The report suggests that NASA could fund a similar public consultation project about SETI, “which truly takes into account current public interests and concerns (instead of presuming to already know what those are).”

Since SETI is not a priority for NASA, this is not going to happen, either.

To be clear, considering the vastness of the universe and what we’ve learned about its evolution and physical and chemical composition, I have no trouble accepting the idea that life could exist, or could have existed, elsewhere. But for me, that’s the end of acceptable assumptions about SETI. No matter how rhetorically or technologically sophisticated the SETI community has become, the work of this community still depends on a pile of assumptions that I deem shaky – that intelligence will evolve in life on other planets, that we know what intelligence is and will recognize it when we encounter it, that extraterrestrial intelligence will be like human intelligence, that human intelligence is the pinnacle of the evolution of intelligence on Earth…. The TS workshop report addresses the limits of various approaches to searching for TSs. Again, considering the vastness of the universe, these limits are, and always have been, a weak point in the rationale for SETI. The chances of finding and verifying a signature are extremely slim. For years, some SETI advocates have been claiming that detection of a signal is imminent. I doubt it.