I see there's now a Wikipedia page for BLC-1, the intriguing SETI detection made by Breakthrough Listen at the Parkes Observatory in Australia. The dataset in which the signal, found at 982 MHz, turned up comes from observations made in April and May of 2019, and it's good to know that Breakthrough is working up two papers on the signal and subsequent analysis, given that the public face of the detection was originally in the form of a story leaked to the British newspaper The Guardian before the backup research was available. Image: CSIRO's Parkes radio telescope in New South Wales, Australia. Credit: Shaun Amy. The first thing to say about BLC-1 is that the acronym stands for Breakthrough Listen Candidate 1, marking the first time a signal has made it through to actual 'candidate' status after five years of observations, which is itself noteworthy given the intensity of the effort. The second thing is that this is a transient, meaning it's short-lived, and it hasn't repeated. That...

Sorry for the server problems the last few days, which resulted in some tinkering under the hood by people far more skilled at such things than I am. Meanwhile, those experiencing deja vu at seeing this post should take heart -- there is a simple explanation. Last week I posted an earlier article about Claudio Maccone's upcoming presentation on gravitational lensing and the FOCAL mission to exploit it, but had to withdraw the post when I realized the live session, a 'webinar' organized by Ravi Kumar Kopparapu (NASA GSFC) and Jacob Haqq Misra (Blue Marble Space Institute of Science), might not be available beyond a restricted audience. Once that was straightened out, the meeting had already occurred, but fortunately Dr. Maccone's session was recorded and is now available here. I'm going to go ahead and run the rest of that earlier post now, because most people didn't see it. Even so, and despite the fact that it was only up on the site for a few minutes, that turned out to be long...

If we ever make a SETI detection, will it be of biological beings or machine intelligence? As Alex Tolley explains in today's essay, there are reasons for favoring the latter possibility, leading our author to compose what he calls a 'light-hearted speculation' about machines searching for other civilizations of their own kind. Life seems to be easy compared to this. We are developing the tools to delve into planetary atmospheres in search of biosignatures, hoping to cull out ambiguities. But is there an equivalent in the machine world of a biosignature, and how would it be found? Interesting implications arise, some of them seemingly close to home. by Alex Tolley Curiosity Rover. Credit Nasa. Terry Bisson's amusing short sci-fi story "They're made Out of Meat" [4], is a communication between two individuals who express their disbelief that a biological species (detected on Earth by a galactic survey) can possibly be intelligent. The denouement is to erase the record of discovery...

Science fiction writers range freely through time, making many scientific papers fertile ground for plot ideas and settings. So here's an extraordinary one. We know that Earth's continents used to be packed into a single large land mass called Pangaea, which is thought to have broken apart about 200 million years ago as tectonic plates shifted. Interestingly, we can expect a remote future in which the continents will have once again come together, as Michael Way (NASA GSFC) has pointed out at an online poster session at the ongoing virtual meeting of the American Geophysical Union. And such a supercontinent has ramifications for habitability. Let's talk about those because they have a bearing on astrobiology as we examine exoplanets and consider their suitability for life. We're a decade or so (at minimum) away from being able to determine how land and sea are distributed on a nearby world, but climate modeling is useful as we look toward estimating habitability. That involves, as...

We're a long way from knowing what is going on in terms of possible life in the clouds of Venus, but one thing is already clear: The phosphine signature, as well as its implications, is going to be thrashed out in the journals, as witness a new study from Rakesh Mogul (Cal Poly Pomona, Pomona, CA) and colleagues that looks at data from the Pioneer-Venus Large Probe Neutral Mass Spectrometer (LNMS), dating back to the Pioneer Venus Multiprobe mission in 1978. These data seem to support the presence of phosphine, while leaving its origin unknown. But Clara Sousa-Silva (Harvard-Smithsonian Center for Astrophysics), who was involved in the earlier phosphine work led by Jane Greaves at Cardiff University (see What Phosphine Means on Venus), subsequently examined data collected in 2015 at Mauna Kea and found no sign of phosphine. And now we have another paper, this one submitted to Science by Ignas Snellen and team (Leiden University), that carries its message in the title: "Re-analysis of...

Keith Cooper's The Contact Paradox is as thoroughgoing a look at the issues involved in SETI as I have seen in any one volume. After I finished it, I wrote to Keith, a Centauri Dreams contributor from way back, and we began a series of dialogues on SETI and other matters, the first of which ran here last February as Exploring the Contact Paradox. Below is a second installment of our exchanges, which were slowed by external factors at my end, but the correspondence continues. What can we infer from human traits about possible contact with an extraterrestrial culture? And how would we evaluate its level of intelligence? Keith is working on a new book involving both the Cosmic Microwave Background and quantum gravity, the research into which will likewise figure into our future musings that will include SETI but go even further afield. Keith, in our last dialogue I mentioned a factor you singled out in your book The Contact Paradox as hugely significant in our consideration of SETI and...

James Gunn may have been the first science fiction author to anticipate the 'new Venus,' i.e., the one we later discovered thanks to observations and Soviet landings on the planet that revealed what its surface was really like. His 1955 tale "The Naked Sky" described "unbearable pressures and burning temperatures" when it ran in Startling Stories for the fall of that year. Gunn was guessing, but we soon learned Venus really did live up to that depiction. I think Larry Niven came up with the best title among SF stories set on the Venus we found in our data. "Becalmed in Hell" is a 1965 tale in Niven's 'Known Space' sequence that deals with clouds of carbon dioxide, hydrochloric and hydrofluoric acids. No more a tropical paradise, this Venus was a serious do-over of Venus as a story environment, and the more we learned about the planet, the worse the scenario got. But when it comes to life in the Venusian clouds -- human, no less -- I always think of Geoffray Landis, not only because...

A biosignature is always going to create a rolling discussion that gradually homes in on a consensus. Which is to say that the recent discovery of phosphine in the upper atmosphere of Venus has inspired a major effort to figure out how phosphine could emerge abiotically. After all, the scientists behind the just published paper on the phosphine discovery seem to be saying something to the community like "We can't come up with a solution other than life to explain this. Maybe you can." The 'maybes' are out there and they include life, but what a tough spot for life to develop, for obvious reasons, not the least of which is the hyper-acidic nature of its clouds. So let's dig into the story a bit more. The idea of life in the cloud layers of an atmosphere has a long pedigree, even on Venus, where discussions go back at least to the 1960s. Harold Morowitz and Carl Sagan examined the matter in a paper in Science in 1967, a speculation that led them to conclude "it is by no means difficult...

As it is considered a precursor installation, the Murchison Widefield Array (MWA) in Western Australia doesn't get the press that its proposed successor, the Square Kilometer Array (SKA) regularly receives. That's to be expected, given the scope of the SKA, which will involve telescopes in both Australia and South Africa. 14 member countries are developing a project that is to reach over a square kilometer of collecting area, containing thousands of dishes and up to a million low-frequency antennas. If it is built, SKA's angular resolution and survey speed will allow surveys thousands of times faster than those now being conducted. But the Murchison precursor is alive and well, working the 70-300 MHz range and mapping the radio sky. Established by a consortium of universities -- MIT, Swinburne, Curtin and Australian National University -- the telescope is located on a site selected by these universities and managed by Curtin University. CSIRO, Australia's national science agency,...

What Breakthrough Listen is calling the most comprehensive SETI search to date is now in the books, or at least, the journals, with results accepted and in process at Monthly Notices of the Royal Astronomical Society. Here we are in the realm of data reanalysis, using previously acquired results to serve as a matrix for re-calculation, with the catalog produced by the European Space Agency’s Gaia spacecraft as the key that turns the lock. No signatures of extraterrestrial technology were detected in the two analyses produced by Breakthrough Listen in 2017 and 2020. The data for these efforts come largely from the Green Bank Telescope (GBT) in West Virginia and the CSIRO Parkes Radio Telescope in Australia, with a focus on 1327 individual stars. Results were published by the Breakthrough Listen science team at UC-Berkeley, and the choice of targets was telling. The search homed in on relatively nearby stars within about 160 light years of the Sun, under the assumption that less...

Beyond its immediate cultural and philosophical implications, the reception of a signal from another civilization will call for analysis across all academic disciplines as we try to make sense of it. Herewith a proposal for an Interstellar Communication Relay, both data repository and distribution system designed to apply worldwide resources to the problem. Author Brian McConnell is an American computer engineer who has written three technical books, two about SETI (the search for extraterrestrial intelligence), and one about electric propulsion systems for spacecraft. The latter, A Design for a Reusable Water-Based Spacecraft Known as the Spacecoach (Springer, 2015) has been the subject of extensive discussion on Centauri Dreams (see, for example, Brian's A Stagecoach to the Stars, and Alex Tolley's Spaceward Ho!). Brian has also published numerous peer reviewed scientific papers and book chapters related to SETI, and is an expert on interstellar communication systems and on...

Given how much we do not know about everything from abiogenesis to the lifetime of technological civilizations, what can we say about SETI's chances for success? Henry Cordova, a Centauri Dreams regular, is a long-time SETI enthusiast who has nonetheless been revising his thinking on the discipline's prospects. Our one useful sample, Earth, tells us how long it took for life just to become multi-cellular, much less to reach the tiny window opened by our technological society. And need we assume that intelligence will inevitably arise even with complex biology to support it? A retired geographer and mapmaker currently living in southeast Florida, Henry served in the US Navy and was originally trained as an astronomer and mathematician. Amateur astronomy, celestial navigation and collecting star atlases occupy his time when he's not pondering questions like how civilization might arise without technology, or whether Dysonian strategies -- looking not for beacons but evidence in the...

Harmonizing with yesterday's post about a NASA grant to study technosignatures is word from Breakthrough Listen, which has released a catalog of what it calls 'exotica' or, to cite the accompanying paper: "an 865 entry collection of 737 distinct targets intended to include "one of everything" in astronomy." The idea is to produce a general reference work that can guide astronomical surveys and, in the case of Breakthrough, widen the search for technosignatures. Brian Lacki (UC-Berkeley), who is lead author of the new catalog, notes that it's not meant to be restricted to SETI, though its uses there may prove interesting. Here are the four categories of exotica the catalog defines: 'Prototypes.' Here the intent is to list one example, perhaps more, an archetype of every known type of non-transient object in the sky. According to the paper, "We emphasize the inclusion of many types of energetic and extreme objects like neutron stars..., but many quiescent examples are included too."...

What a pleasure to see -- after three decades -- a grant from NASA for a SETI project, and on technosignatures at that. NASA's history with SETI has been a challenging one given the subject's reception in Congress. It was in 1971 that the agency funded Barney Oliver's study on the huge array called Project Cyclops, whose price-tag would have been astronomical, but the report in which it was described provided numerous insights into the SETI effort. NASA's engagement with SETI later came under fire from William Proxmire in the Senate, resulting in the termination of SETI funding in 1982. Proxmire would later change his mind on SETI's value. Even so, the NASA Microwave Observing Program (MOP) planned as a search of 800 nearby stars in the early 1990's was again targeted in Congress and canceled shortly thereafter. The SETI effort developed in the ensuing years without government funding through efforts like Project Phoenix, which picked up the Mobile Observing Program under the...

Yesterday we looked at a new paper from Robert Gray on the possibility -- even likelihood -- that the kind of signal SETI is looking for would be intermittent in nature rather than continuous. The numbers tell the story: In Gray's calculations, an isotropic transmission with a range of 1,000 light years -- i.e., a continuous beacon broadcasting in all directions -- requires on the order of 1015 W to produce the kind of signal-to-noise ratio that would allow us to pick it up with facilities like those used in current SETI searches. 1015 is a big number, going beyond the current terrestrial power consumption of 1013 W by orders of magnitude and reaching 1 percent of the total power received by Earth from the Sun. Reduce the desired range of the signal to 100 light years and the requirement for isotropic broadcasts is still daunting, demanding something like 1013 W, or 10,000 1,000 MW power plants. As Gray puts it: The large power required for continuous isotropic broadcasts could...

My guess is that most people think of SETI as doing a 'long stare' at a given star, on the theory that it may take time to acquire a possible signal from an extraterrestrial civilization. But in reality observations take place over short time periods. The Mega-channel ExtraTerrestrial Assay, known by its acronym as META, led by Harvard's Paul Horowitz and aided by The Planetary Society, could only devote a few minutes to any particular star. The same was true of the follow-on BETA (Billion-channel Extraterrestrial Assay), while targeted searches like Phoenix, led by Jill Tarter and using facilities at Green Bank (West Virginia), the Parkes 64-meter dish in Australia and the 300 meter radio telescope at Arecibo, still observed targets for less than an hour. The problem with this is that there are numerous reasons why an extraterrestrial signal might be intermittent. We've looked at this issue before, particularly in terms of 'Benford beacons,' as discussed by Greg and Jim Benford in...

When Ken Wisian and John Traphagan (University of Texas at Austin) published "The Search for Extraterrestrial Intelligence: A Realpolitik Consideration" (Space Policy, May 2020), they tackled a problem I hadn't considered. We've often discussed Messaging to Extraterrestrial Intelligence (METI) in these pages, pondering the pros and cons of broadcasting to the stars, but does SETI itself pose issues we are not considering? Moreover, could addressing these issues possibly point the way toward international protocols to address METI concerns? Ken was kind enough to write a post summarizing the paper's content, which appears below. A Major General in the USAF (now retired), Dr. Wisian is currently Associate Director of the Bureau of Economic Geology, Jackson School of Geosciences at UT. He is also affiliated with the Center for Space Research and the Center for Planetary Systems Habitability at the university. A geophysicist whose main research is in geothermal energy systems, modeling,...

If we could somehow rewind time to the earliest days of the Solar System and start over again, would life -- and intelligence -- reappear? It's an experiment science fiction authors are able to try, but it defies real world science. Nonetheless, we can make approaches to the problem through the analysis of probabilities. In particular, we can use statistics, and the technique known as Bayesian inference, which weighs probabilities updated by new evidence. This is a helpful exercise given that so often I hear people referring to the idea that intelligent life must be everywhere because the universe is so vast and there are so many opportunities for it to arise. But does life inevitably emerge on what we might consider habitable worlds? What if this process of abiogenesis is rare? The question points to the fact that we have absolutely no idea what the likelihood is, and therefore assumptions about intelligent life based solely on numerical opportunity are nothing but speculations....

In our continuing look at biosignatures that could flag the presence of life on other worlds, we've sometimes considered the so-called 'red edge,' the sharp change in reflectance of vegetation that shows up in the near-infrared. It's worth remembering that vegetation is the largest reflecting surface on Earth (about 60 percent of the land surface), with an increase in reflectance that shows up around 700 nm. As Alex Tolley explains below, the red edge may shift depending on the evolution of plant life and the variables, including light intensity but comprising many other factors, that would affect life on M-dwarf planets. These are the first whose atmospheres we'll be seriously examining for biosignatures, and the question of how to extrapolate from Earth life to environments as exotic as these is complex. A Centauri Dreams regular, Alex reminds us that vegetative life may prove adaptable in ways that will surprise us. by Alex Tolley Artist’s conception of Proxima Centauri b. Credit:...

Is seeding life into the universe to be a part of the human future? Space probes conceivably could be doing this inadvertently, and the processes of panspermia also may be moving biological possibilities between planets and even stars. Robert Buckalew has his own take on what humans might do in this regard, as discussed below. Robert has written fiction and non-fiction since 2013 under the pen name Ry Yelcho for the blog Yelcho's Muses. In 2015 he received the Canopus Award for Excellence in Interstellar Fiction from 100 Year Starship for the story "Everett's Awakening." His short story "The Interlopers" appears on Literally Stories. What follows draws on his speculative science article "Microbots—The Seeds of Interstellar Civilization," which was awarded the Canopus Award for Original Non-Fiction. The essay that follows is based on his presentation at the Icarus Interstellar Starship Congress 2019. by Robert Buckalew The series of pivotal events that led to the development of...