Monday, June 19
Technosignatures and the Oxygen Bottleneck
Adam Frank
In this talk we explore the relationship between atmospheric oxygen and the development of technological civilizations. Our concern is the possibility that only planets with significant oxygen partial pressures, P(O_2), will be capable of developing “advanced” technological civilizations and hence detectable technosignatures. Consideration of the processes required for a young intelligent species (in the sense of being technologically capable) demonstrates the need for easy access to combustion as a source of energy. But open air combustion is only possible when P(O_2) > 18 %. We argue this sets a limit on the atmospheric concentrations of O_2 that will be required for a technological civilization utilizing, for example, metallurgy. We further review other possible planetary atmospheric compositions and argue that only O_2 will be suitable for the evolution of technological species. Thus the presence of P(O_2) > 18 % may represent a contextual prior required for the planning of technosignature searches.
Are there ‘hard steps’ on the road to intelligence?
Daniel Mills
The evolution of human intelligence on Earth required certain prerequisites, such as the evolution of eukaryotes and oxygenic photosynthesis. According to the hard steps model, some of these evolutionary prerequisites were ‘hard’, in the sense that they were unlikely to occur in the time available for all life on Earth (even though these prerequisites necessarily did occur, given our existence). This hard-steps scenario was originally inspired by the observation that humans evolved near the mid-point of the Sun’s main sequence lifetime – not on time scales orders of magnitude smaller. However, the Earth sciences have shown that human life has only been supported by the biosphere – at least with respect to atmospheric oxygen (O2) – for the past 9% of Earth history. As an alternative to the hard steps model, humans may have evolved ‘on time’ in the middle of a non-random global-environmental window that has only opened recently in geologic time and will indeed close again in the geologic near future. In this talk, I will explain how Earth history can be read to support such a conclusion.
The Alien Hypothesis in the Context of Experimental Design
David Kipping
From looking for microfossils on Mars to biosignatures on Trappist-1e, from seeking radio transmissions to extraterrestrial artefacts, there’s a diverse range of approaches to seeking life in the Universe. Common to all is the central goal of testing the “alien hypothesis” – in other words, is there life beyond Earth? Critics of SETI (and indeed previously astrobiology) casually lob around the claim that it’s “not real science”, but arguably the most universally accepted definition of a valid scientific hypothesis is that it’s amenable to being tested experimentally. Here, I explore the alien hypothesis from this general perspective in hope of identifying a unifying framework suitable from astrobiology to SETI. The alien hypothesis features three qualities that delineate it from traditional, palatable scientific hypotheses, which I will explore in this talk. As an example of one of these, if we search for alien life by seeking biosignatures and find no such signal, that does no mean there is no alien life at the target planet (it could be hidden under the surface for example). The alien hypothesis, very generally, has the property of having unbounded evasiveness and in fact we can never falsify the hypothesis of alien life on Trappist-1e (or indeed anywhere else), at least stated in that way. I’ll share my thoughts on these challenging problems, the statistical consequences in experimental design, and welcome discussion from the audience to framing our searches upon a positive and rigorous scientific foundation.
Review Talk: Post-Detection in the 2020s: Navigating Discovery
Kathryn Denning
The SETI Protocols were an important early effort to define SETI researchers’ responsibilities to the world in terms of scientific reliability, transparency, and restraint (i.e. no unilateral responses to incoming transmissions). Now, 3 decades later: potential technosignatures and biosignatures search and discovery scenarios are increasingly diverse, generating new questions and ethical issues; the players involved have changed and multiplied; multiple ‘false alarms’/ rehearsals have occurred; popular culture involving ETI is proliferating; the UAP/UFO discussion has evolved; human expansion into our solar system is brewing; many consider eventual interstellar missions to be realistic, with myriad implications; AI is developing quickly, as are concepts of postbiological ETI; abundant scientist-generated speculation and debate about ETI is in the public domain; attempts among scientists to achieve consensus regarding outbound transmissions have not succeeded; the global news media landscape has changed significantly; social media is a dominant force with very rapid content dissemination and a spectrum of social interaction from friendly to abusive; public attitudes towards science are diverse and sometimes daunting; climate change is increasingly recognized worldwide as an escalating existential threat, but global agreements have been difficult; and, finally, mis/disinformation has reached astonishing proportions, with serious real-world consequences. All this change has extensive implications for a technosignatures discovery and its consequences. How should the technosignatures community navigate now? What is in your control, and what isn’t? What answers to crucial and predictable questions could you give to global publics after a discovery?
Rebecca Charbonneau
The roots of SETI: (Extra)Terrestrial Intelligence Revisited
Gabriela Radulescu
The talk is based on my doctoral thesis which explores a particular episode in the history of Soviet-Western scientific cooperation, namely the interdisciplinary conceptualization of human contact with extraterrestrial intelligence across the Iron Curtain from the early 1960s until the mid-70s. The publication of the article ‘Searching for Interstellar Communications’ by the physicists Phillip Morrison and Giuseppe Cocconi in Nature in 1959 marks the beginning of a strong debate in science on intelligent extraterrestrial life. While the SETI historiography has mostly focused on individual, small-scale, or national contributions of scientists to the topic of extraterrestrial intelligence, the transnational character of such knowledge has been only very recently studied. My research draws attention to the force of scientific internationalism in the extraterrestrial intelligent life debate. I aim to edify the specific ways in which science, diplomacy, and law are intertwined in the international quest for extraterrestrial intelligence. In offering a revision of the current view on the extraterrestrial intelligent life debate in the twentieth century, I show how the notion of extraterrestrial intelligence as a modern Western scientific epistemic object took shape through a conversation between the two politically divided parts.
Tuesday, June 20
Advances in Exopsychology
Niklas Döbler
Based on seminal works by Robert Freitas and Albert A. Harrison from the 1980s and ‘90s, exopsychology is concerned with how extraterrestrials think. Recently Döbler and Raab (2021) re-proposed this idea. By defining exopsychology as the psychological discipline that investigates the cognition, behavior, affects, and motives of extraterrestrial agents and their human-specific representation, Döbler and Raab proposed to focus not solely on the minds of hypothetical extraterrestrials but how humans think about them. This opens up a perspective for empirical psychology and other humanities and social sciences. Since the first contact has not occurred yet, exopsychological research concerning the extraterrestrial side is limited to theoretical thoughts. However, several studies have been published over the last decades investigating human thinking about extraterrestrials. This talk aims at providing a comprehensive perspective on the theoretical and empirical research that can be linked with the exopsychological research agenda.
What is the underlying structure of the belief in extraterrestrials? Could we be only concerned with finding them because we feel lonely? Do they provide meaning to the vastness of space? How do astrobiologists evaluate the probability of life in the solar system? And do we really need the elusive concept of intelligence?
So gained insights can be employed to increase SETI’s success probability. But even if first contact will never happen: By evaluating how we think about extraterrestrials, Exopsychology contributes to an all-to-human effort: enhancing our understanding of ourselves.
The Power of Collaborating with Artists in the Search for Life
Jack Madden
The images and figures we use to communicate science contain many subjective pitfalls that require creative training to avoid. Scientists hold enormous responsibility for shaping and sharing reality with the public through the stories and images they inspire. With the search for life being complex and as much sentiment driven as it is scientifically driven, the effectiveness of our communication will rely more heavily on graphics, figures, and titles. Having my Ph.D. in exoplanet habitability and M.F.A. in digital media, I am keenly aware of the missed potential in collaboration between art and science in such a paradigm-shifting moment. In my talk, I will provide some context for the power of visuals to alter scientific narratives and give pointers on how to thoughtfully approach making figures and working with artists for significant scientific discoveries. I will use the Wow signal, Earthrise, the Allan Hills photo, the Pale Blue Dot, Lowell’s Martian canals, and pictures from Hubble and Webb to illustrate how the prevailing public narrative of science can be visually (mis)guided. Examples will be provided on how to discuss your science with artists to avoid misinterpretation and to understand the power artists have in the way your work is understood at large. Particular emphasis will be placed on the looming challenge of communicating a spectral biosignature detection with the public and how we might meet it.
[Allen Telescope Array Talk]
Wael Farah
Miltibeam Search for techno-signatures on RECONS targets with ATA
Ramiro Saide
Exploring the possibility of life beyond our planet has been a long-standing area of interest in the scientific community, the Search for Extraterrestrial Intelligence (SETI) aims at unraveling the question of whether life exists beyond our planet. SETI research is primarily focused on the detection of “techno-signatures,” or artificial signals that cannot be generated by natural emission mechanisms, as a means of identifying evidence of intelligent life beyond Earth.
Here we report on primary results from observations conducted with the Allen Telescope Array (ATA). The ATA is a 42-element radio interferometer hosted at the Hat Creek Radio Observatory, ~4 hours drive north of San Fransisco. The ATA is sensitive between 1 and 11 GHz, and hosts a flexible DSP backend that allows the digitization of 4 tunings of ~680 MHz each anywhere in the RF band. The observations of the sample of stars presented here were carried out between March and April, conducted across the C-band and X-band between 3350 and 9650 MHz. Our sample of targets was selected from The Research Consortium On Nearby Stars (RECONS), a database established in 1994 to discover “missing” members of the solar neighborhood and to characterize the complete sample of nearby star systems and their environment.
Using the multi-beam capabilities of the ATA, we observed 226 stars for 5 minutes each, covering the entire frequency band mentioned above. Our strategy was to place a “beam” on the target of interest, and another set of beams towards the edge of the telescope’s field of view, allowing for simultaneous “ON” and “OFF” cadence observations, essential to filter out candidates due to Radio Frequency Interference (RFI). The ATA pipeline produced high spectral resolution data dedicated to searching for narrowband signals. The analysis conducted in this project focused on detecting narrowband signals that drift in frequency over the course of the observation due to the Doppler effect. Using the traditional Turboseti approach, we found various signals, each with its own particularities. Although no evidence of technosignatures were found during our search, this work represents the first (of many) surveys of nearby stars conducted with the refurbished ATA and its revamped signal processing system.
The Longest Stare at TRAPPIST-1 with the Allen Telescope Array
Nick Tusay
The Allen Telescope Array was used to observe the TRAPPIST-1 system for 28 hours over 8 observations during the end of October and the beginning of November, 2022. Beam forming software was employed to spatially resolve data from two points within the field of view, one being the target of interest, TRAPPIST-1. The signals from these spatially distinct beams were then correlated and their similarity scored for radio frequency interference (RFI) rejection. RFI should naturally be highly correlated in both beams, while signals localized to the target should exhibit low correlation with the other beam. The results of this analysis are presented here.
Wednesday, June 21
Earth Detecting Earth: Human Baselines for Technosignatures
Macy Huston
We explore the current technological capabilities of Earth, both in terms of technosignature emission and detection, establishing standards for the Search for Extraterrestrial Intelligence (SETI). We use the concept of the “ichnoscale,” to quantify the relative intensity of technosignatures in units of the same technosignature as produced by Earth’s technology (Socas-Navarro et al. 2021). Using this “Earth Detecting Earth” strategy, we quantify over what distance we could, using current or near-future astronomical detection capabilities, detect a variety of manifestations of present-day Earth technology. We consider the following technological categories: radio transmissions (e.g. METI, planetary radar, and human communication leakage), atmospheric pollutants, surface geoengineering, artificial satellites, and optical laser leakage. These values can help guide expectations in the search for extraterrestrial technology.
Schelling Points in SETI
Jason Wright
If there are signals from ETIs intended for us to find, where should we look for them? The question is as old as modern SETI, appearing in the very first SETI papers (arguing for searches in the “Water Hole”). I will explore the history of the idea, including Thomas Schelling’s formalization of it in his foundational work in game theory, in which he describes “focal points” (now called “Schelling points”) as equilibria in a noncommunicative cooperative game. I will discuss many of the suggestions for Schelling points in SETI in frequency, time, and physical space, and how they can be profitably applied today with the advent of billion-channel radio receivers and all-sky surveys.
Alien Motivations and their Technosignature Search Approaches
Nick Siegler
NASA’s Exoplanet Exploration Program is conducting a fact-finding study capturing the multitude of ways scientific investigators are searching for signs of technosignatures from potential alien civilizations. One of the fascinating results of this nearly completed study is a mapping between envisioned alien motivations and the approaches investigators are taking to search for them. In this talk, I will review a nearly complete list of technosignature search approaches (some of which you may have never heard of). I will also highlight the creativity of original, artificially generated digital images used to illustrate some of the speculative alien motivations.
SETI India: A Search For Technosignatures with the uGMRT
Raghav Girgaonkar
The discovery of the ubiquity of habitable extrasolar planets, combined with revolutionary advances in instrumentation and observational capabilities, has ushered in a renaissance in the search for extraterrestrial intelligence (SETI). The Breakthrough Listen (BL) program is a US $100M effort of 10 years to conduct the most sensitive, comprehensive, and intensive search for advanced life on other worlds ever performed. Despite the large scale radio SETI activities at numerous observing facilities, there exists a dearth of continuous frequency coverage between 300 MHz and 1 GHz. Upgraded Giant Metrewave Radio Telescope’s (uGMRT) operation capability at these frequencies makes it a desired and complimentary instrument with ongoing SETI activities. The uGMRT also provides unique opportunities to capture phased array beam voltages parallel with interferometric imaging visibilities. We present our ongoing efforts in SETI, which is of the first kind in India, to capture the raw stream of data products from the uGMRT and conduct searches for novel signals likely to be produced by the activities of advanced ETIs. These signals include; (1) continuous-wave narrowband signal with spectral occupancy of < 1 Hz, and (2) broadband transient signals with artificial dispersion. We introduce our data processing pipeline developed for SETI with uGMRT. We will also discuss some of the initial results obtained from the analysis done on the phased array spectral voltage (PASV) data from uGMRT using our software pipeline. To analyze the performance of the pipeline, we also developed strategies to inject artificially narrowband and broadband signals directly into the raw stream of voltages. We further demonstrate that long baselines of GMRT provide band-limited spectral imaging and temporal window imaging capabilities which are helpful to scrutinize the extraterrestrial origin of putative signals from ETI.
A 4-8 GHz Search of the Galactic Center for Periodic Technosignatures
Ashkay Suresh
Radio searches for extraterrestrial intelligence have primarily targeted the discovery of narrowband continuous-wave beacons and artificially dispersed broadband bursts from alien worlds. Periodic pulse trains, in contrast, offer an energetically efficient means of interstellar transmission. In particular, a rotating beacon at the Galactic Center (GC) would be advantageous for galaxy-wide communications. Here, we describe a novel open-source software that utilizes a fast folding algorithm (FFA) to conduct searches for channel-wide periodic signals in radio dynamic spectra. Running our software on 4.5 hours of 4–8 GHz data from the Robert C. Byrd Green Bank Telescope, we searched the central 6’ of our Galaxy for kHz-wide signals with periods between 11–100 s and duty cycles between 10–50%. Our searches, to our knowledge, represent the first FFA exploration for periodic spectral signals. We will present our first constraints on the abundance of extraterrestrial worlds transmitting periodic signals from the GC. Finally, we will highlight the utility of our software at detecting periodic astrophysical signals with exotic radio frequency sweeps departing from the cold plasma dispersion law.
A Large Scale Search for Intelligent Life with Commensal Observations at the VLA
Chenoa Tremblay
Radio telescopes offer a practical way to search the vast distances of space for radio communication signals from other worlds. However, due to the naturally large problem for the search across the 9-dimensional parameters (such as location, frequency, and time), we have only touched the surface of this search for the needle in the “cosmic haystack”. One of the main challenges for the search for extraterrestrial intelligence (SETI) is gaining access to telescopes with any continuous regularity. New commensal systems on sensitive radio telescopes, which can complete SETI surveys in real-time along with regular telescope operations, is revolutionary. Now instead of 1000s of sources over a 5-year observing campaign we will search towards millions of stellar systems per year. One of the newest commensal systems is COSMIC – Commensal OpenSource Multimode Interferometric Cluster – on the Karl G. Jansky Very Large Array (VLA). In this talk I will provide an overview of COSMIC and the VLA, our search strategies, and our results so far in the first 6 months of operation.
The PANOSETI Transient Search
Nicholas Rault-Wang
We have designed and prototyped a novel optical and near-infrared observatory to greatly enlarge the current SETI phase space. The Pulsed All-sky Near-infrared Optical SETI (PANOSETI) observatory will be a dedicated SETI facility that aims to increase sky area searched, wavelengths covered, number of stellar systems observed, and duration of time monitored. This observatory offers the capability to simultaneously search a 4,450 square degree field of view for optical and near-infrared transient pulsed signals occurring between nanosecond-to-second time scales. The PANOSETI design employs two precisely synchronized domes separated by ~1 km to distinguish atmospheric phenomena from astrophysical events and potential technosignatures. Each dome contains 24 to 45 low-cost PANOSETI telescopes for panoramic sky coverage. Each PANOSETI telescope covers a 10° by 10° patch of sky and uses a 0.5 m Fresnel lens to focus light onto a nanosecond-resolution 1024-pixel silicon photomultiplier camera. PANOSETI facilitates high-speed data acquisition with cluster computing architecture along with 1440 ASICs and 360 FPGAs in the instrumentation. We have deployed a prototype PANOSETI observatory at Lick Observatory where we also plan to build a full-scale system. We present an overview of the PANOSETI project.
The 2821 Star Southern Hemisphere Optical SETI Survey
Benjamin Laszlo Fields
We conducted a single observation survey of archival reduced spectra from 2821 stellar targets taken by the HARPS spectroscope for potential signatures of lasers from extraterrestrial civilizations. The HARPS instrument has a wavelength range and sensitivity which makes it an ideal instrument to search for narrow emission spikes that might originate from lasers. We searched for narrowband spikes and established a classification system to identify false positives, including cosmic rays, bleedthrough from the Th-Ar calibration lamp, night sky airglow lines, and large clusters of emission lines which may be the product of natural stellar activity. Of the 2821 stellar spectra we analyzed, we identified 294 candidates with at least one narrow spectral emission feature. 29.3% of these candidates appeared to be in clusters indicative of natural emission lines. Through visual inspection of the raw CCD images, we found cosmic rays to be the most common type of false positives, accounting for 47.6% of all candidates. Bleedthrough from the calibration lamp accounted for 2.4% of all candidates and 3.1% of candidates were night sky atmospheric airglow lines which evaded our initial screening for them. From the 17.7% of remaining candidate observations, we then eliminated spikes whose line width was narrower than the point-spread function of the instrument, arguing that these must be cosmic ray hits or other non-optical phenomena. This procedure left 16 candidates. Two of these have prosaic explanations–a previously unaccounted for calibration lamp bleed through and emission activity from an eruptive variable star. We are currently left with 14 candidates worthy of further consideration as potential technosignatures. To distinguish reproducible signals from single detections, we then looked for additional detections in all other available observations of these 14 stars. We found 35 additional hits which also passed our curve fitting filter in these 1775 additional observations, but only one case in which a spike was observed at the same wavelength as the original candidate.
Where No Telescope Has Gone Before: Opportunities and Challenges for SETI with LSST
Tansu Daylan
The Legacy Survey for Space and Time (LSST) will be a deep, wide, and fast survey of the southern sky over ten years. Its unique rapid cadence, sensitivity, unprecedented étendue, and broad wavelength coverage will enable exciting opportunities for the Search for Extraterrestrial Intelligence (SETI) while introducing new computational and theoretical challenges. We discuss LSST’s prospects of detecting solar system objects on parabolic or hyperbolic orbits originating from exoplanetary systems, anomalous non-gravitational accelerations of solar system bodies, and the broader class of photometric technosignatures based on color and variability that will be observationally accessible to LSST. We highlight potential pitfalls of current approaches in data reduction and transient alerts and suggest areas of improvement for improving LSST’s capabilities for SETI under the emerging survey cadence optimization strategies. In particular, we make a case for SETI-focused coordination among existing LSST working groups to enable groundbreaking discoveries.
Project Hephaistos – Dyson sphere candidates
Matias Suazo
The quest for intelligent extraterrestrial life has captivated humanity for a long time, and various strategies have been developed to search for signs of advanced civilizations. One intriguing approach involves looking for indirect evidence of extraterrestrial technology, such as the presence of Dyson spheres. These hypothetical megastructures, constructed by advanced civilizations, would encompass a star to harness its energy and potentially emit detectable infrared radiation. Missions such as Gaia, 2MASS, and WISE provide extensive observations which can be utilized for identifying potential Dyson spheres. In this work, we developed a pipeline to gather sources that exhibit unusual infrared radiation not easily attributable to known astronomical sources. We have encountered various challenges and false positives throughout our search, which we will discuss. These challenges include distinguishing between sources exhibiting blends, irregular structures, and nebular features. Additionally, we present several candidates with intriguing characteristics that deserve further analysis and discuss some potential explanations for the infrared excess.
Thursday, June 22
A Sign in Space: an interdisciplinary exploration of the potential reception of an extraterrestrial signal
Daniela de Paulis
A Sign in Space is an interdisciplinary project by media artist Daniela de Paulis, in collaboration with the Green Bank Observatory, the Italian National Institute for Astrophysics, the SETI Institute and the European Space Agency.
The project consists in transmitting a simulated extraterrestrial message as part of a live performance, using an ESA spacecraft as celestial source. The objective of the project is to involve the world-wide Search for Extraterrestrial Intelligence community, professionals from different fields and the broader public, in the reception, decoding and interpretation of the message. This process will require global cooperation, bridging a conversation around the topics of SETI, space research and society, across multiple cultures and fields of expertise.
Review: SETI and the Theoretical Humanities
Armando M. Mastrogiovanni
This talk is drawn from research surrounding my book-in-progress, The Astrobiological Turn: Theories of Life Beyond the Terrestrial Imagination.
In recent years, SETI has inspired new work in the humanities. It’s no surprise that scholars in fields like literary studies would produce research related to SETI. But can the methods of the humanities offer anything to SETI in return? I propose that the answer is yes.
This talk places the theoretical humanities and SETI into dialogue. It reviews the humanities not as a collection of fields defined by specific subject-matters, but as a set of methods and conceptual approaches that can be employed across disciplines. Here, I make the case that the “theoretical humanities” of the twentieth-century (encompassing phenomenology, structural linguistics, and poststructuralism) offer powerful conceptual tools that may prove valuable to SETI.
Those tools are concerned with meaning, which I divide into two senses:
1. The first sense of “meaning” is that given to it by phenomenology. This is the “aboutness” we implicitly attribute to consciousness. I trace the phenomenological approach to meaning from its roots in the philosophical work of Edmund Husserl to contemporary science, where it informs the theoretical biology of Humberto Maturana and Francisco Varela, and also current work by the astrobiologist Adam Frank and the philosopher Evan Thompson. Their theory of science’s “blind spot,” which is directly pertinent to SETI, has phenomenological roots. The first part of my review makes those roots and their import for SETI explicit.
2. The second sense of “meaning” is linguistic. This is meaning as it is traditionally understood by disciplines like philology and hermeneutics, which are dedicated to the study of how meaning is produced, translated, and interpreted. The key innovation of the twentieth-century theoretical humanities was to view “meaning” as an emergent effect. I explore how this rethinking of meaning can be brought to bear on the question of meaning as it is posed by SETI.
SETI is fundamentally concerned with the problem of meaning in both senses. Its core ambition is to discover intelligent life beyond Earth by identifying signs of technological activity. A technosignature is the sign of meaningful activity. And yet the meaning itself is by definition alien and inaccessible. What is it possible to know about alien meaning? How can it be interpreted? Even translated? The theoretical humanities offers surprising answers.
The Mantras of Astrobiology: Leading and Misleading Metaphors
Clément Vidal
Astrobiologists conduct a science-based search for life or intelligent life. Such a search is inevitably guided by human concepts and metaphors. Some metaphors can be useful, while others can be misleading. They can even become “mantras” that few analyze or question anymore.
In this talk, we discuss and disentangle key mantras of astrobiology, organized in two categories: epistemology and search-space. The epistemological mantras include: bio/techno “signatures”, “I know it when I see it”, Clarke’s “any sufficiently advanced technology is indistinguishable from magic”, “alien-of-the-gaps”, as well as Sagan’s: life is the hypothesis of last resort, extraordinary claims require extraordinary evidence, absence of evidence is not evidence of absence (resp. Carl Sagan et al. 1993; “Cosmos” 1980; Carl Sagan 1995, 200).
Second, we analyze search-space metaphors and concepts: looking through a “magic frequency”, looking for “low hanging fruits”, looking for the “needle in the haystack”, generalized in the “cosmic haystack” (Wright, Kanodia, and Lubar 2018), looking for lost keys beneath the halo of a street lamp (Arnould 2013).
Raising awareness of strengths and weaknesses of the key mantras of astrobiology brings essential insights to pursue our quest for life beyond Earth in the most rigorous and least biased ways.
References:
Arnould, Jacques. 2013. “Astrobiology: The Next Revolution?” In The History and Philosophy of Astrobiology: Perspectives on Extraterrestrial Life and the Human Mind, edited by David Dunér, Gustav Holmberg, and Erik Persson. Cambridge Scholars Publishing.
“Cosmos.” 1980. Episode 12, 1:24 Directed by C. Sagan.
Sagan, Carl. 1995. The Demon-Haunted World: Science as a Candle in the Dark. 1st ed. New York: Random House.
Sagan, Carl, W. Reid Thompson, Robert Carlson, Donald Gurnett, and Charles Hord. 1993. “A Search for Life on Earth from the Galileo Spacecraft.” Nature 365 (6448). Nature Publishing Group: 715–21. doi:10.1038/365715a0.
Wright, Jason T., Shubham Kanodia, and Emily Lubar. 2018. “How Much SETI Has Been Done? Finding Needles in the n-Dimensional Cosmic Haystack.” The Astronomical Journal 156 (6). American Astronomical Society: 260. doi:10.3847/1538-3881/aae099.”
A Continued Search for Technosignatures during Planet-Planet Occulations
Evan Sneed
Over the past decade, increases in funding and advancements in computational power have given SETI practitioners the opportunity to make great strides in searching through the cosmic haystack. However, these technosignature searches have often focused on individual stars and relied on the assumption that detectable artificial signals are persistent over long time frames. Inspired by communication networks already established within the solar system, we identified a method to eavesdrop on potential “spillover” that could be detectable when two or more exoplanets are collinear with Earth. This scenario, known as a planet-planet occultation, provides both a time and place to search for technosignatures and is sensitive to both deliberate transmission attempts and communications not intended for Earth. In this work, N-body orbital models influence when observations for potential communications occur, allowing astronomers to determine when is best to search for technosignature candidates and schedule observations. In this presentation, we will update the community on progress made regarding the N-body orbital models used to determine when planet-planet occultations are most likely to occur. We also provide an analysis of both archival and recent observations for planet-planet occultations using data taken from the Green Bank Telescope, the Parkes Radio Telescope, and the Allen Telescope Array.
A search for technosignatures around nearly 10,000 stars with the Green Bank Telescope at 1.15-1.73 GHz
Jean-Luc Margot
As part of our ongoing search for technosignatures, we observed 46 additional regions of the sky in 2020-2022 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope (GBT). Each region spanned the ~8 arcmin FWHM beam of the GBT and was centered on a planetary system that has been recently discovered, primarily by NASA’s TESS mission. This component of our search sampled 9524 stars and yielded approximately 24 million narrowband detections, bringing the cumulative number of stars sampled by our program to ~41,000 and the number of detections to ~64 million. The data were analyzed with the UCLA SETI data-processing pipeline, which automatically classified the vast majority (99.6%) of these signals as anthropogenic Radio Frequency Interference (RFI). The remaining signals were further examined with machine learning techniques (Pinchuk and Margot, AJ 163, 2022) and visual inspection by thousands of citizen scientists (Li and Margot, this meeting). In addition to our search results, we will also describe how we quantify the overall detection efficiency of radio SETI data-processing pipelines. We have injected thousands of artificial signals in raw voltage data and recovered 94.1% of these signals with our pipeline. Outside regions of dense RFI, the efficiency increases to 98.2%. The most common misses occur at the bandpass edges and when signals intersect in time-frequency space. These results are broadly consistent with a prior analysis (Margot et al., AJ 161, 2021) that relied on insertion of artificial signals in dynamic spectra.
Are we alone in the universe?
Megan Li
“Are we alone in the universe?” is a Zooniverse-based citizen science project designed to accelerate the Search for Extraterrestrial Intelligence (SETI). The project launched on February 14, 2023 and is accessible at http://arewealone.earth
Volunteers are presented with spectrograms of narrowband radio signals, and tasked to answer a few questions about each signal’s structure. These answers enable progress through a decision tree and result in the classification of each signal into one of twenty categories. Along the way, volunteers highlight the most promising technosignatures. The final product is a labeled set of spectrograms. We will use this labeled set to train a machine learning application to excise radio frequency interference (RFI) from future SETI searches.
The signals that are classified on Zooniverse have been pre-selected out of 66 million candidate signals as the most likely to be generated by extraterrestrials.
Funded by NASA, The Planetary Society, and generous donors, “Are we alone in the universe?” has already inspired over 12,000 volunteers who have collectively submitted over 380,000 classifications and generated a labeled training set with over 25,000 entries.
Technosignatures with TESS: A Search for Anomalies
Ann Marie Cody
Through its set of full frame images, the Transiting Exoplanet Survey Satellite (TESS) is
observing tens of millions of stars at 30-minute cadence. The resulting light curves are being used to study a variety of sources, from transiting exoplanet systems, to spotted stars, to pulsators. But with such a large dataset, there may also be new or unappreciated types of stellar variability. With TESS’s predecessor, Kepler, astronomers and citizen scientists indeed identified a handful of stars undergoing unexplained fading events. The most well known of these– Boyajian’s star–ignited interest in stellar occultation phenomena. While most fading events are likely caused by the passage of dust in front of a star, alternative explanations lie with larger objects such as exocomets or even artificial structures put in place by intelligent civilizations.
We have been performing a search for anomalous variability in the first two years of TESS
observations (sectors 1-26), via means of statistical and machine learning techniques.
We discuss our general approach, highlighting both aperiodic behavior and repeated
fading caused by one or more occulting screens. This effort has required careful
differentiation between authentic variability phenomena and spacecraft or background-related systematic effects, some of which can cause abrupt but artificial brightness decreases. We present here our most anomalous stars found to date, culled from among millions of candidates, as well as plans to further vet these objects.
Report from the first SETI with LSST Workshop
James Davenport
The upcoming Legacy Survey of Space and Time (LSST) on the Vera C. Rubin Observatory will be a landmark photometric survey that impacts nearly every area of astrophysics. The potential for this survey to advance technosignature research for both archival and real-time studies is substantial yet under-explored. This is in part due to a lack of collaboration and communication between core SETI and LSST researchers.
In January 2023 we held the first “SETI with LSST” workshop at the University of Washington. This workshop brought together traditional technosignature researchers and members of the Rubin/LSST technical community to engage in a day of collaboration and project development. Here I report on discussions from this exciting event, and invite the PSETI community to participate in an upcoming whitepaper.