Seminar and Journal Club

Chelsea Haramia
October 7, 2021
Zoom recording

Abstract:
The Search for ExtraTerrestrial Intelligence (SETI) attempts to answer the question: Are we alone in the universe? I show that the nature of the search itself requires committing to an irrational choice. I then show that, by extension, this search raises questions regarding our moral obligations to future generations. Though all such searches involve some degree of irrationality, one method of searching—passive SETI—is more compatible with our moral obligations to future generations. Its alternative—METI (Messaging ExtraTerrestrial Intelligence) has four features that, taken together, entail that it is both less rational to pursue than passive SETI, and that it is also less morally justified. These features are: transformativeness, irreversibility, independence, and opacity. I conclude that passive SETI is the only morally defensible method of searching for extraterrestrial intelligence, and that it is reasonable to pursue it insofar as we wish to discover who we as humans will become.

Clément Vidal
September 23, 2021
Zoom recording

Abstract:
I discuss the idea that technosignatures might be sifted out of existing data. I illustrate this possibility through the stellivore hypothesis, which I introduce through three stories: bypassing the heat death of the universe, extrapolating energetic and technological trends on Earth, and investigating intriguing accreting binary star systems. I describe some epistemological and historical problems related to choosing a model through old and recent historical debates (e.g. geocentrism and heliocentrism; the Martian meteorite ALH84001 or ‘Oumuamua). I outline some core enduring anomalies or complications in the physics of accreting binaries, and argue that they are compatible with a living or technological interpretation. I open the discussion on how to further probe the stellivore hypothesis.

Jason Wright
September 16, 2021
Zoom recording

Abstract:
I will review the SETI literature from 2020. I’ll take a look at what was studied, how the community is collectively spending its efforts, and where it is publishing.

James Howell
September 10, 2021
Zoom recording

Abstract:
In the past twenty years, the number of confirmed exoplanets has jumped 150 fold (< 40 before 2000, > 4,800 in 2021) and that total is likely to continue to grow rapidly. Informed efforts to narrow the search for biosignatures and technosignatures to most-likely “habitable zones” are thus increasingly required. Relevant to this goal, there is a long tradition of efforts to build parametric frameworks describing likely scenarios for the necessary sequence of (1) emergence of life, (2) emergence of complex life, and (3) emergence of intelligence leading to technological civilization. These attempts have been guided by biology (e.g. “evolutionary transitions”) or physical and statistical first principles (“hard steps”). Both categories of concepts provide preliminary analytical tools, but both suffer from fundamental conceptual and practical flaws. We will discuss a framework for analysis that proceeds from the contemporary biological consensus on the natural history of this biosphere, and attempts to generalize to (very) different planetary conditions.

Greg Eghigian
September 3, 2021
Zoom recording

Abstract:
Science is a verb. It is a knowledge-producing, knowledge-distributing, and knowledge-consuming set of activities. And it’s worth bearing in mind, it is only one of many such enterprises. How then has science tried to maintain its integrity in the face of fields deemed to be “pseudoscience?” This talk explores the relationship between ufology and the academic sciences by tracing the social history of how scientists have addressed what atmospheric physicist James McDonald referred to as “the UFO problem” and the research it inspired.

Cherry Ng
April 29, 2021
Zoom recording

Abstract:
The search for technosignatures – remotely observable indicators of advanced extraterrestrial life – addresses one of the most profound questions in science: are we alone in the universe as intelligent life? The Breakthrough Listen program is leading the most concerted search for extraterrestrial intelligence (SETI) effort to-date through radio and optical surveys of nearby stars, nearby galaxies and the Milky Way galactic plane, thus representing the best chance the human race has ever had to detect a technosignature. Recently, Breakthrough Listen has partnered with the SETI Institute to develop commensal SETI search capabilities on some of the most sensitive radio inteferometers, including the Allen Telescope Array (ATA), the Very Large Array (VLA) and MeerKAT. Interferometric radio telescopes have the advantage of providing a larger field of view, maximizing the SETI survey speed. In this talk, we will present the latest updates on these surveys and conclude with a refreshed outlook on SETI search using next generation telescope facilities.

Daniel Czech, Breakthrough Listen, UC Berkeley
April 15, 2021
Zoom recording

Abstract:
New radio telescope arrays offer unique opportunities for large-scale commensal SETI surveys. Ethernet-based architectures are allowing multiple users to access telescope data simultaneously by means of multicast Ethernet subscriptions. Breakthrough Listen will take advantage of this by conducting a commensal SETI survey on the MeerKAT radio telescope in South Africa. Both coherent and incoherent observing modes are planned. We present the list of desired sources for observation and explain how these sources were selected from the Gaia DR2 catalog. Given observations planned by MeerKAT’s primary telescope users, we discuss their effects on the commensal survey and propose a commensal observing strategy in response. We also outline our proposed approach toward observing one million nearby stars and analyze expected observing progress in the coming years.

Daniel Giles, SETI Institute
April 1, 2021
Zoom Recording

Abstract:
Over the last decade, NASA has launched two major space missions that were designed to collect photometry data over a large swath of sky: the Kepler telescope and Transiting Exoplanet Survey Satellite (TESS) have each monitored hundreds of thousands to millions of stars on sub-hour cadence over month or longer timescales, respectively. Stellar brightness fluctuations observed by these missions encode a diverse range of phenomena, from outbursts and explosions, to exoplanetary transits, to asteroseismic pulsations. If there are other advanced civilizations in the galaxy, we may also be able to detect their “technosignatures” via monitoring large numbers of stars. In particular, artificial structures around a host star (e.g., Dyson swarms; Dyson 1960) may produce pronounced and distinctive fading events in light curves. This possibility was recently brought to the forefront with the discovery of Boyajian’s Star (KIC 8462852), which displayed erratic brightness dips. Various hypotheses have been put forth for the behavior of this object, from artificially-engineered megastructures to transiting exocomets.

While no theory provides a perfect explanation for the fading events seen in Boyajian’s star, the large volume of imaging data emerging from the TESS mission is now enabling a new search for similar behavior in additional objects. Our team is using a combination of supervised and unsupervised machine learning to discover and classify rare fading events. We will follow up on the most unusual objects with ground-based optical and radio observatories to determine the origin of such variability. Ultimately, this program will either discover or put an upper limit on the frequency of transiting artificial megastructures around main sequence stars in our galaxy.

Manasvi Lingam, Florida Institute of Technology
March 18, 2021
Zoom recording

Abstract:
The significance of commensal searches for technosignatures in the context of characterizing exoplanets is increasingly being recognized. In this talk, I will outline the notion of “service worlds”, i.e., hypothetical worlds exclusively oriented toward specific technological activities. I will subsequently discuss some examples of possible service worlds, their putative decoupling from biosignatures, and the advantages insofar as technosignature detection is concerned. The relevance of these service worlds to the Drake equation and the ensuing ramifications for future technosignature surveys will also be sketched.

Avi Loeb, Harvard University
February 2, 2021
Zoom Recording

Abstract: