Search For Extraterrestrial Intelligence Research Articles

Rio 2.0: revising the Rio scale for SETI detections

AbstractThe Rio scale is a tool for communicating the significance of a signal to the general public. It assigns scores to signals detected in searches for extraterrestrial intelligence (SETI), which characterizes both the consequences of a signal and the probability the signal is truly from ETI, in an easily digestible format for laypeople to interpret. In the 17 years since its construction, the number of groups actively conducting searches for evidence of intelligent life beyond the Earth has increased significantly, and theoretical work has established a new suite of observables that are capable of revealing the presence of ETI in a range of astronomical observations. In this paper, we revise the Rio scale, with the aim of (i) achieving consensus across academic disciplines on a scheme for classifying signals potentially indicating the existence of advanced extraterrestrial life, (ii) supplying a pedagogical tool to help inform the public about the process scientists go through to develop an understanding of a signal and (iii) providing a means of calibrating the expectations of the world at large when signals are discussed in the media. We also present (and encourage the SETI community to adopt) a single set of consistent terminology for discussing signals.

Active SETI in Solar system neighborhood

In the search for habitable planets, the ultimate aspiration is finding an extraterrestrial technical civilization. We already lost a half of century for an active search for extraterrestrial civilizations. Should we lose another half? If all civilizations in the Universe are only recipients and not message-sending civilizations, then no SETI (Search for Extraterrestrial Intelligence) searches make any sense. Detecting only leaked radio signals is a hard job with present resources. Fear from the extraterrestrials is unfounded, having in mind physical difficulties and requirements of the interstellar travel. If possible extraterrestrial civilizations are more advanced than ours then they can pick up life signs from Earth easier than we can from their planets at present. Here we propose a scientifically based METI (Messaging to Extraterrestrial Intelligence) program.

A Game of Stars: Active SETI, radical translation and the Hobbesian trap

Among scholars dedicated to Search for Extra-terrestrial Intelligence (SETI), the risks and possibilities of actively contacting extra-terrestrials (Active SETI) have been widely discussed. Yet, some fundamental philosophical problems concerning the possibility of translating an alien language have hardly been raised in this context. The proponents of Active SETI assume that, abswould an extra-terrestrial intelligent (ETI) entity choose to contact us, they would use radio signals to convey a coded message that would be possible for us to decode and translate. Furthermore, they argue, were we to transmit a message, then this message would also be possible to translate. However, any interstellar message would, for obvious reasons, be conveyed without context and without the possibility of meaningful interaction over timescales relevant to us.According to the most influential research program in the philosophy of language, the meaning of an utterance is derived from its use in a context and is not intrinsic to the utterance by which it was conveyed. Therefore, while radical translation, i.e. learning an unknown language, is possible, it requires contextualized interaction. Only then can semantic behavior be observed, and utterances linked to meaning. Thus, merely an exchange of signals cannot produce meaningful communication. If this claim is true, there are important game-theoretical consequences of interstellar contact. An informal game theoretical analysis of this scenario, A Game of Stars, is described. This analysis suggests that the lack of communication may lead players into a Hobbesian Trap, where fear impels the players to a risk dominant strategy, potentially resulting in mutual destruction. Our conclusion is that interstellar contact is an underestimated existential risk. If true and given the relative ease of contacting an ETI given the knowledge of its location, information about the existence and location of an ETI would be very dangerous to spread. Thus, knowledge of an ETI and its location would constitute an information hazard.

Exploring optical SETI's middle ground

The Search for Extra-Terrestrial Intelligence (SETI) in optical wavelengths has recently concentrated either on detecting intense short light pulses that briefly outshine the background star or on finding unique features that stand out in the star's spectrum. But there is a middle ground available where the temporal variation of an optical SETI source would distinguish it from its stellar background. Initial results are presented for frequency-domain searches, covering a signal range of 1–10,000 Hz, with an instrument that simultaneously measures two broad optical spectral bands. It is shown that signals a thousand times fainter than the background starlight can be detected using this instrument coupled to a meter-class telescope. Since these signals can be either positive or negative (i.e. a periodic obscuration), the intriguing possibility exists of detecting signals where no energy need be intentionally beamed toward Earth.

Carl Sagan: Etička pitanja

The aim of this paper is to present dr. Carl Sagan's ethical issues within his own exobiological researches, and the criticism of such a view. We shall start from Dr. Sagan's anthropological definition where his view on intelligence as demarcation criteria between species, ecological issues on preservation of life on Earth, terraforming, exobiology, and SETI project (search for extraterrestrial intelligencies), up to the abortion controversy, will be set forth.

Policy options for the radio detectability of Earth

The METI risk problem refers to the uncertain outcome of sending transmissions into space with the intention of messaging to extraterrestrial intelligence (METI). Here, I demonstrate that this uncertainty is undecidable by proving that that the METI risk problem reduces to the halting problem. This implies that any proposed moratorium on METI activities cannot be based solely on the requirement for new information. I discuss three policy resolutions to deal with this risk ambiguity. Precautionary malevolence assumes that contact with ETI is likely to cause net harm to humanity, which remains consistent with the call for a METI moratorium, while assumed benevolence states that METI is likely to yield net benefits to humanity. I also propose a policy of preliminary neutrality, which suggests that humanity should engage in both SETI (searching for extraterrestrial intelligence) and METI until either one achieves its first success.

A Serendipitous MWA Search for Narrowband Signals from ‘Oumuamua

Abstract We examine data from the Murchison Widefield Array (MWA) in the frequency range 72–102 MHz for a field of view that serendipitously contained the interstellar object ‘Oumuamua on 2017 November 28. Observations took place with a time resolution of 0.5 s and a frequency resolution of 10 kHz. Based on the interesting but highly unlikely suggestion that ‘Oumuamua is an interstellar spacecraft, due to some unusual orbital and morphological characteristics, we examine our data for signals that might indicate the presence of intelligent life associated with ‘Oumuamua. We searched our radio data for (1) impulsive narrowband signals, (2) persistent narrowband signals, and (3) impulsive broadband signals. We found no such signals with nonterrestrial origins and make estimates of the upper limits on equivalent isotropic radiated power (EIRP) for these three cases of approximately 7 kW, 840 W, and 100 kW, respectively. These transmitter powers are well within the capabilities of human technologies, and are therefore plausible for alien civilizations. While the chances of positive detection in any given search for extraterrestrial intelligence (SETI) experiment are vanishingly small, the characteristics of new generation telescopes such as the MWA (and, in the future, the Square Kilometre Array) make certain classes of SETI experiments easy, or even a trivial by-product of astrophysical observations. This means that the future costs of SETI experiments are very low, allowing large target lists to partially balance the low probability of a positive detection.

Invasion percolation solves Fermi Paradox but challenges SETI projects

AbstractNon-homogeneous fractal-like colonization processes, where the cluster of visited sites has large voids and grows slowly, could explain the negative results of Search for Extraterrestrial Intelligence (SETI) preserving the possibility of a galactic spanning civilization. Here we present a generalized invasion percolation model to illustrate a minimal colonization process with large voids and delayed colonization. Spatial correlation between unvisited sites, in the form of large empty regions, suggests that to search civilizations in the Sun neighbourhood may be a misdirected SETI strategy. A weaker form of the Fermi Paradox also suggests this last conclusion.

A Search for Extraterrestrial Intelligence (SETI) toward the Galactic Anticenter with the Murchison Widefield Array

Abstract Following the results of the first systematic modern low-frequency search for extraterrestrial intelligence using the Murchison Widefield Array (MWA), which was directed toward a Galactic Center field, we report a second survey toward a Galactic Anticenter field. Using the MWA in the frequency range 99–122 MHz over a three-hour period, a 625 deg2 field centered on Orion KL (in the general direction of the Galactic Anticenter) was observed with a frequency resolution of 10 kHz. Within this field, 22 exoplanets are known. At the positions of these exoplanets, we searched for narrowband signals consistent with radio transmissions from intelligent civilizations. No such signals were found with a 5σ detection threshold. Our sample is significantly different to the 45 exoplanets previously studied with the MWA toward the Galactic Center, since the Galactic Center sample is dominated by exoplanets detected using microlensing, and hence at much larger distances than the exoplanets toward the Anticenter, found via radial velocity and transit detection methods. Our average effective sensitivity to extraterrestrial transmitter power is therefore much improved for the Anticenter sample. Added to this, our data processing techniques have improved, reducing our observational errors, leading to our best detection limit being reduced by approximately a factor of four compared to our previously published results.

Strategic Ignorance and the Search for Extraterrestrial Intelligence: Critiquing the Discursive Segregation of UFOs from Scientific Inquiry

ABSTRACTSince the late 1940s, a tenacious disconnect between popular interest and professional disinterest in unidentified flying objects (UFOs) has typified the controversy surrounding the subject. Numerous high-profile scientists have seen the topic of UFOs as an opportunity to denounce and rectify a popular, yet allegedly misguided, conviction—that some UFOs are physical anomalies indicating the existence of extraterrestrial intelligence—and thus to advance the explanatory authority of science. Rather than constituting rigorous, informed, and effective assessments, however, the ways in which many prominent scientists publicly address the UFO question often exemplify both the problematic “boundary-work” of scientific discourse in this area and, more specifically, the role that logical fallacies can play in the rhetorical construction of scientific authority in public domains. Through a critical discourse analysis, this article argues that ignorance of UFO phenomena is socially and discursively constructed in ways that are conducive to the public faces of individuals and institutions. More broadly, it suggests that the rudimentary standard of science communication attending to the extraterrestrial intelligence (ETI) hypothesis for UFOs inhibits public understanding of science, dissuades academic inquiry within the physical and social sciences, and undermines progressive space policy initiatives.

The Impact of the Temporal Distribution of Communicating Civilizations on Their Detectability.

We used a statistical model to investigate the detectability (defined by the requirement that causal contact has been initiated with us) of communicating civilizations within a volume of the Universe surrounding our location. If the civilizations are located in our galaxy, the detectability requirement imposes a strict constraint on their epoch of appearance and their communicating life span. This, in turn, implies that our ability to gather empirical evidence of the fraction of civilizations within range of detection strongly depends on the specific features of their temporal distribution. Our approach illuminates aspects of the problem that can escape the standard treatment based on the Drake equation. Therefore, it might provide the appropriate framework for future studies dealing with the evolutionary aspects of the search for extraterrestrial intelligence (SETI). Key Words: Astrobiology-Extraterrestrial life-SETI-Complex life-Life detection-Intelligence. Astrobiology 18, 54-58.

Anthropomorphism in the search for extra-terrestrial intelligence – The limits of cognition?

The question “Are we alone?” lingers in the human mind since ancient times. Early human civilisations populated the heavens above with a multitude of Gods endowed with some all too human characteristics – from their outer appearance to their innermost motivations. En passant they created thereby their own cultural founding myths on which they built their understanding of the world and its phenomena and deduced as well rules for the functioning of their own society. Advancing technology has enabled us to conduct this human quest for knowledge with more scientific means: optical and radio-wavelengths are being monitored for messages by an extra-terrestrial intelligence and active messaging attempts have also been undertaken. Scenarios have been developed for a possible detection of extra-terrestrial intelligence and post-detection guidelines and protocols have been elaborated. The human responses to the whole array of questions concerning the potential existence, discovery of and communication/interaction with an extra-terrestrial intelligence share as one clear thread a profound anthropomorphism, which ascribes classical human behavioural patterns also to an extra-terrestrial intelligence in much the same way as our ancestors attributed comparable conducts to mythological figures. This paper aims at pinpointing this thread in a number of classical reactions to basic questions related to the search for extra-terrestrial intelligence. Many of these reactions are based on human motives such as curiosity and fear, rationalised by experience and historical analogy and modelled in the Science Fiction Culture by literature and movies. Scrutinising the classical hypothetical explanations of the Fermi paradox under the angle of a potentially undue anthropomorphism, this paper intends to assist in understanding our human epistemological limitations in the search for extra-terrestrial intelligence. This attempt is structured into a series of questions: I. Can we be alone? II. Who are we looking for? III. Or what are we looking for? IV. Where is everybody? V. What if we make contact and VI. So, what now?

The Evolutionary Psychology of Extraterrestrial Intelligence: Are There Universal Adaptations in Search, Aversion, and Signaling?

To understand the possible forms of extraterrestrial intelligence (ETI), we need not only astrobiology theories about how life evolves given habitable planets, but also evolutionary psychology theories about how intelligence emerges given life. Wherever intelligent organisms evolve, they are likely to face similar behavioral challenges in their physical and social worlds. The cognitive mechanisms that arise to meet these challenges may then be copied, repurposed, and shaped by further evolutionary selection to deal with more abstract, higher-level cognitive tasks such as conceptual reasoning, symbolic communication, and technological innovation, while retaining traces of the earlier adaptations for solving physical and social problems. These traces of evolutionary pathways may be leveraged to gain insight into the likely cognitive processes of ETIs. We demonstrate such analysis in the domain of search strategies and show its application in the domains of emotional aversions and social/sexual signaling. Knowing the likely evolutionary pathways to intelligence will help us to better search for and process any alien signals from the search for ETIs (SETI) and to assess the likely benefits, costs, and risks of humans actively messaging ETIs (METI).

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

We report on a search for engineered signals from a sample of 692 nearby stars using the Robert C. Byrd Green Bank Telescope, undertaken as part of the $Breakthrough~Listen~Initiative$ search for extraterrestrial intelligence. Observations were made over 1.1$-$1.9 GHz (L band), with three sets of five-minute observations of the 692 primary targets, interspersed with five-minute observations of secondary targets. By comparing the "ON" and "OFF" observations we are able to identify terrestrial interference and place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. During the analysis, eleven events passed our thresholding algorithm, but a detailed analysis of their properties indicates they are consistent with known examples of anthropogenic radio frequency interference. We conclude that, at the time of our observations, none of the observed systems host high-duty-cycle radio transmitters emitting between 1.1 and 1.9 GHz with an Equivalent Isotropic Radiated Power of $\sim10^{13}$ W, which is readily achievable by our own civilization. Our results suggest that fewer than $\sim$ 0.1$\%$ of the stellar systems within 50 pc possess the type of transmitters searched in this survey.

On the Plausibility of Intelligent Life on Other Worlds

AbstractThe apprehension of the last three factors of the Drake equation, fi · fc · L, is misguided or at least not very well examined. This article scrutinizes the underlying suppositions involved in the search for extraterrestrial intelligence (SETI) research. What is meant by “intelligence,” “technology,” and “civilization”? What makes them possible, and how do they evolve? The present examination aims to arrive at a more well-founded search for extraterrestrial intelligence that takes into account current research within cognitive science, the history of technology, and the history of socialization. What we need is a cognitive-semiotic approach to the extent, distribution, and evolution of extraterrestrial intelligence. The three variables fi · fc · L concern how an extraterrestrial biosphere evolves cognitively flexible organisms that, through a biocultural coevolution, acquire an increasing capability to manipulate the surrounding environment for the purpose of transferring shared mental states. In addition, this has to last for a period of time long enough to coincide with the relatively brief existence of Homo sapiens sapiens.

The BVIT: from Flare Stars to the Search for ET

AbstractThe Berkeley Visible Image Tube (BVIT) has been a user instrument on the SALT 10-m telescope for the past six years. It can observe transient astrophysical phenomena occurring on time-scales of micro-seconds. This overview presented some recent observations of a dMe flare star, and discussed the recent results of our optical Search for Extraterrestrial Intelligence (OSETI) around nearby exoplanet-hosting stars.

C&EN talks with Sherry Cady, astrobiologist

Was there life on Mars? If so, microorganisms would have left chemical signatures in martian rocks, as they have done here on Earth. Astrobiologist Sherry Cady of Pacific Northwest National Laboratory is helping Mars mission teams from the National Aeronautics & Space Administration decide where to search for fossilized evidence of life on the red planet. As a member of the SETI Institute team that is part of the NASA Astrobiology Institute, she studies Earth environments that are analogs for potential ecosystems on Mars, including hot springs, deserts, and the remains of ancient lakes. She talked with Deirdre Lockwood about how these extreme environments inform the search for life in outer space. How did you first get interested in this field? During my postdoc at NASA’s Ames Research Center, they sent me out to Yellowstone National Park in Wyoming to look at high-temperature geological formations at the hot springs. These

Pulsar science at the Sardinia Radio Telescope

AbstractThe Sardinia Radio Telescope (SRT) is a modern, fully-steerable 64-m dish located in San Basilio, Sardinia (Italy). It is characterized by an active surface that allows it to cover a wide range of radio frequencies (300 MHz to 100 GHz). During SRT’s commissioning phase, we installed the hardware and software needed for pulsar observations. Since then, SRT has taken part in Large European Array for Pulsars and European Pulsar Timing Array observations for the purpose of gravitational wave detection. We have installed a new S-band receiver that will allow us to search for pulsars in the Galactic Center. We also plan to combine our efforts to search for Extraterrestrial Intelligence (SETI) with the search for pulsars and Fast Radio Bursts.

The Magnetoionic Universe: Timing, Bursts, and SETI

AbstractPropagation effects have been central to pulsar research and indeed were an integral part of the pulsar discovery and its prologue. I will summarize the early deduction process for establishing pulsar distances and refinements to the distance scale and modeling of the Galaxy in electron density and magnetic field. This will lead to the analogous current situation of understanding distances and media for extragalactic radio bursts. The role of magnetoionic media in precision pulsar timing and surveys for transients will be summarized. Finally, going full circle, searches for extraterrestrial intelligence (LGMs) also require attention to propagation effects.

Can the periodic spectral modulations observed in 236 Sloan Sky Survey stars be due to dark matter effects?

The search for dark matter (DM) is one of the most active and challenging areas of current research. Possible DM candidates are ultralight fields such as axions and weak interacting massive particles (WIMPs). Axions piled up in the center of stars are supposed to generate matter/DM configurations with oscillating geometries at a very rapid frequency, which is a multiple of the axion mass mB (Brito et al (2015); Brito et al (2016)). Borra and Trottier (2016) recently found peculiar ultrafast periodic spectral modulations in 236 main sequence stars in the sample of 2.5 million spectra of galactic halo stars of the Sloan Digital Sky Survey (∼1% of main sequence stars in the F–K spectral range) that were interpreted as optical signals from extraterrestrial civilizations, suggesting them as possible candidates for the search for extraterrestrial intelligence (SETI) program. We argue, instead, that this could be the first indirect evidence of bosonic axion-like DM fields inside main sequence stars, with a stable radiative nucleus, where a stable DM core can be hosted. These oscillations were not observed in earlier stellar spectral classes probably because of the impossibility of starting a stable oscillatory regime due to the presence of chaotic motions in their convective nuclei. The axion mass values, , obtained from the frequency range observed by Borra and Trottier, ) THz, agree with the recent theoretical results from high-temperature lattice quantum chromodynamics (Borsanyi et al (2016); Borsanyi et al (2016b)).