How do you produce life on an early Earth bathed in ultraviolet radiation? The presumption when I was growing up was that the combination of chemicals in ancient ponds, fed energy by lightning or ultraviolet light itself, would produce everything needed to start the process. Thus Stanley Miller and Harold Urey's experiments, beginning in 1953 at the University of Chicago, which simulated early Earth conditions to produce amino acids out of a sealed 'atmosphere' of water, ammonia, methane and hydrogen, with electrodes firing sparks to simulate lightning. But there are other ways of explaining life's origins, as a new study from the Jet Propulsion Laboratory and the Icy Worlds Team at the NASA Astrobiology Institute reminds us. Hydrothermal vents on the sea floor have been under consideration since the 1980s, with some researchers pointing to the 'black smokers' that produce hot, acidic fluids. The new NASA work looks at much cooler vents bubbling with alkaline solutions like those in...
SETI at the Particle Level
A big reason why the Fermi paradox has punch is the matter of time. Max Tegmark gets into this in his excellent new book Our Mathematical Universe: My Quest for the Ultimate Nature of Reality (Knopf, 2014), where he runs through what many thinkers on the subject have noted: Our Sun is young enough that countless stars and the planets that orbit them must have offered homes for life long before we ever appeared. With at least a several billion year head start, wouldn't intelligent life have had time to spread, and shouldn't its existence be perfectly obvious by now? Tegmark's book is fascinating, and if you're interested in learning why this dazzling theorist thinks it likely we are the only intelligent life not just in our galaxy but in our universe, I commend it to you (although Fermi issues play only the tiniest of roles in its overall themes). I'll have plenty of occasion to get into Tegmark's ideas about what he believes to be not just a multiverse but a multiply-staged...
Habitability Around Ancient Stars
I see a lot to like about Abraham Loeb’s new paper “The Habitable Epoch of the Early Universe,” available as a preprint and now going through the submission process at Astrobiology. Not that it isn’t controversial, and for reasons that are patently obvious as soon as one digs into it. But the sheer chutzpah of postulating that microbial life might have started up no more than ten or fifteen million years after the Big Bang takes the breath away. This is a notion that extends life so far back that it defies our conventional models of how it formed. Temperatures aren’t the problem, given that radiation in the early universe would have produced cozy conditions for a multi-million year window of time as what is now called the cosmic microwave background (CMB) continued to cool. The problem is that we have to get from hydrogen and the helium created by fusion in the Big Bang furnace to heavy elements that are usually explained by large stars seeding the cosmos with supernovae explosions....
Is Energy a Key to Interstellar Communication?
I first ran across David Messerschmitt's work in his paper "Interstellar Communication: The Case for Spread Spectrum," and was delighted to meet him in person at Starship Congress in Dallas last summer. Dr. Messerschmitt has been working on communications methods designed for interstellar distances for some time now, with results that are changing the paradigm for how such signals would be transmitted, and hence what SETI scientists should be looking for. At the SETI Institute he is proposing the expansion of the types of signals being searched for in the new Allen Telescope Array. His rich discussion on these matters follows. By way of background, Messerschmitt is the Roger A. Strauch Professor Emeritus of Electrical Engineering and Computer Sciences at the University of California at Berkeley. For the past five years he has collaborated with the SETI institute and other SETI researchers in the study of the new domain of "broadband SETI", hoping to influence the direction of SETI...
Moving Stars: The Shkadov Thruster
Although I didn’t write about the so-called ‘Shkadov thruster’ yesterday, it has been on my mind as one mega-engineering project that an advanced civilization might attempt. The most recent post was all about moving entire stars to travel the galaxy, with reference to Gregory Benford and Larry Niven’s Bowl of Heaven (Tor, 2012), where humans encounter an object that extends and modifies Shkadov’s ideas in mind-boggling ways. I also turned to a recent Keith Cooper article on Fritz Zwicky, who speculated on how inducing asymmetrical flares on the Sun could put the whole Solar System into new motion, putting our star under our directional control. The physicist Leonid Shkadov described a Shkadov thruster in a 1987 paper called “Possibility of Controlling Solar System Motion in the Galaxy” (reference at the end). Imagine an enormous mirror constructed in space so as to reflect a fraction of the star’s radiation pressure. You wind up with an asymmetrical force that exerts a thrust upon...
SETI, METI… and Assessing Risk like Adults
David Brin is a familiar name to science fiction readers worldwide, the award-winning author of the highly regarded 'uplift' novels that include Startide Rising (1983), The Uplift War (1987) and Brightness Reef (1995). Among his numerous other titles are The Postman (1985), Kiln People (2002) and Existence (2012). But Brin is also known as a futurist whose scientific work ranges over topics in astronautics and astronomy to forms of dispute resolution and the role of neoteny in human evolution. His Ph.D in Physics from the University of California at San Diego followed a masters in optics and an undergraduate degree in astrophysics from Caltech. He was a postdoctoral fellow at the California Space Institute and the Jet Propulsion Laboratory. Brin has served on advisory committees dealing with subjects as diverse as national defense, space exploration, SETI and nanotechnology, future/prediction and philanthropy. His essay The Great Silence (available here) is but one of his many...
James Benford: Comments on METI
Pardon this extended introduction to Jim Benford's response to Nick Nielsen's Friday essay, but it comes at a serendipitous time. Jim's recent online work has reminded me that we in the interstellar community need to work to see that as many resources as possible are made available online. In the absence of specialized bibliographies, useful information can be hard to find in more general indices. And it's always dismaying to read an intriguing abstract only to realize that the paper itself is behind a pricey firewall. Access to academic libraries certainly helps, but online databases still vary in what they make available, which is why I always check the home pages of the authors of a given paper to see if they have posted a copy of their work themselves. Scientists can do much to get the word out, as Jim's new site attests. You'll find it at http://jamesbenford.com/. Over the weekend, after Nick had discussed METI (Messaging to Extraterrestrial Intelligence) on Friday, I resorted...
SETI, METI, and Existential Risk
To broadcast or not to broadcast? The debate over sending intentional signals to other stars continues to simmer even as various messages are sent, with no international policy in place to govern them. Writer Nick Nielsen looks at METI afresh today, placing it in the context of existential risk and pondering the implications of what David Brin has dubbed the 'Great Silence.' If risk aversion is our primary goal, do we open ourselves to a future of permanent stagnation? Or is announcing ourselves to the universe something we have any real control over, given the ability of an advanced civilization to detect our presence whether we send messages or not? Mr. Nielsen, a contributing analyst with online strategic consulting firm Wikistrat, wonders whether our counterparts around other stars aren't wrestling with the same issues. by J. N. Nielsen At the Icarus Interstellar Starship Congress in Dallas last August I had the good fortune to be present for James Benford's talk about METI,...
SETI: Looking for von Neumann Probes
In a recent paper outlining a novel strategy for SETI, Michael Gillon (Université de Liège) makes a statement that summarizes what Robert Forward began saying back in the 1970s and even earlier. Interstellar flight is extraordinarily difficult, but not beyond the laws of physics: Our technology is certainly not yet mature enough to build a probe able to reach one of the nearest stars in a decent time (i.e. within a few decades), but nothing in our physical theories precludes such a project. On the contrary, the constant progress in the fields of space exploration, nanotechnology, robotics and electronics, combined with the development of new possible energy sources like fusion reactors or solar sails, indicate that interstellar exploration could become a technological possibility in the future, provided that our civilization persists long enough. That last issue about the survival of our society is the L variable in the Drake equation, referring to the lifespan of any...
Comet Impacts and the Origin of Life
It was back in 2010 that Nir Goldman (Lawrence Livermore National Laboratory) first predicted that the impact of a comet on the early Earth could produce potential life-building compounds like amino acids. Goldman was using computer simulations to make the call, studying molecular dynamics under the conditions of such impacts. He found that the shock of impact itself should produce amino acids and other prebiotic compounds, regardless of conditions on the planet. It was intriguing work because it suggested that impacts in the outer system (think Enceladus, for example) could produce enough energy to create the shock synthesis of prebiotics there. Now Goldman, working with collaborators from Imperial College London and the University of Kent, has gone beyond the simulations to test the process in the laboratory. By firing a projectile into a mixture comparable to the material found on a comet -- water, ammonia, methanol and carbon dioxide -- the team was able to produce several...
Remembering John Billingham
Michael Michaud is no stranger to these pages, with a number of prior contributions and a reputation that precedes him in the field of SETI and interstellar research at large. Among his accomplishments are a lengthy career in the U.S. Foreign Service, where he served as Counselor for Science, Technology and Environment at U.S. embassies in Paris and Tokyo, and Director of the State Department's Office of Advanced Technology. His involvement with SETI is lengthy and includes chairing working groups at the International Academy of Astronautics and numerous articles and papers. His book Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials (Springer, 2007) is an indispensable contribution to the growing body of SETI literature. Today Michael reflects on the life of his friend and colleague John Billingham, who died on August 4 at the age of 83. by Michael Michaud One of the true pioneers of SETI has left us. John Billingham played a major role in...
Remembering The Listeners
Back in the 1970s I ran across an essay by James Gunn called "Where Do They Get Those Crazy Ideas," which was all about how science fiction worked and where its writers sought inspiration. I had long admired Gunn, a college professor who was developing a body of critical work on science fiction even as he continued to publish taut, interesting stories like those I had seen collected in Station in Space (1958) and The Joy Makers (1961). A story first published in Galaxy called "The Cave of Night" had particularly haunted me and led me to seek out more of his work. On the spur of the moment, I wrote Gunn a brief note of appreciation for the essay on writing, not thinking I would hear back from him, but sure enough a letter swiftly appeared inviting me to come to Kansas that summer, where he would be leading a science fiction workshop. That was a trip I wasn't able to schedule, but I kept an eye on Gunn's writing and finally, some years after its publication, sat down to read The...
Catching Up with FOCAL
Michael Chorost has written a fine essay on Claudio Maccone's FOCAL mission concept for The New Yorker blog. Centauri Dreams regulars will know Chorost from several previous posts here, particularly a discussion on SETI that I talked about in On Cosmic Isolation, where he analyzed the hunt for extraterrestrial civilizations in terms of problems of perception, with reference to his own thoughts on deafness, cochlear implants and neurotechnology. Mike is the author of the superb World Wide Mind (Free Press, 2011) that examines the interface between future humans and future machines. I also like to remind readers of something Mike wrote on his own blog last year, which refers to a book I deeply admire and issues I'll be writing about in future essays here. In particular, how do we deal with advanced alien civilizations if we run across them, and would the gap between us and them defeat our attempts at communication? Chorost takes a positive view: I'd like to be optimistic. I'd like to...
SETI’s Colossus
For the most part, the focus of SETI since Project Ozma has been directed at intercepting signals deliberately sent our way. It doesn’t have to be so, of course, because extraneous signals from a civilization going about its business would also be profoundly interesting, and even a civilization not much more advanced than ours might be throwing off powerful evidence of its existence through the planetary radars it uses to detect potential impactors in its own system. Whether or not the Ohio State WOW! signal was a SETI detection remains unresolved, but I always think back to the original Cocconi and Morrison paper “Searching for Interstellar Communications,” published in Nature in 1959. Neither man could know in that year whether exoplanets even existed, but it was a reasonable supposition, and technology had advanced to the point where detecting SETI signals was consistent with all we knew. And as the duo wrote: “The probability of success is difficult to estimate, but if we never...
Robotic Replicators
Centauri Dreams regular Keith Cooper gives us a look at self-replication and the consequences of autonomous probes for intelligent cultures spreading into the universe. Is the Fermi paradox explained by the lack of such civilizations in the galaxy, or is there a far more subtle reason? Keith has been thinking about these matters for some time as editor of both Astronomy Now and Principium, which has just published its fourth issue in its role as the newsletter of the Institute for Interstellar Studies. Intelligent robotic probes, as it turns out, may be achievable sooner than we have thought. by Keith Cooper There's a folk tale that you'll sometimes hear told around the SETI or physics communities. Back in the 1940s and 50s, at the Los Alamos National Labs, where the first nuclear weapons were built, many physicists of Hungarian extraction worked. These included such luminaries in the field as Leó Szilárd, Eugene Wigner, Edward Teller and John Von Neumann. When in 1951 their...
Finding ET in the Data
As we saw yesterday, the Infrared Astronomical Satellite (IRAS) has been the source of data for a number of searches for unusual infrared signatures. The idea is to look for the artifacts of advanced extraterrestrial civilizations, under the assumption that a sufficiently advanced culture will be capable of engineering projects that could be detected from light years away. A Dyson sphere, existing either as a completely enclosed star or as a swarm of artifacts around a star, is but one example of such engineering, but it's a sensible one to look for because it represents a way to maximize energy. It's also theoretically detectable because of waste heat in the infrared. These days, though, we have not just IRAS but the Wide-field Infrared Survey Explorer (WISE) and the Spitzer space telescope providing us with infrared data. Richard Carrigan's pioneering work on interstellar archaeology is now complemented by searches funded by the New Frontiers in Astronomy & Cosmology program, set...
Archaeology on an Interstellar Scale
Dyson spheres -- technology wrapped around an entire star to maximize energy use -- would be unimaginably big. But the idea of maximizing the light from a central star certainly makes sense. Imagine a sphere with a radius at the distance of Earth’s orbit. Now you’ve got a surface area more than 100 million times what’s available on our planet, a sensational venue for science fiction if nothing else. And you’re certainly changing the energy equation -- our total power consumption today is the equivalent of about 0.01 percent of the sunlight falling on Earth, according to a new article in New Scientist. Keep energy demand growing at 1 percent per year and in a single millennium we’ll need more energy than strikes the surface of the planet. Moving power generation into space is certainly something that would motivate a civilization a good deal more advanced than our own, and using abundant asteroid material, it could spread power generation entirely around the star. Stephen Battersby,...
SETI: The Artificial Transit Scenario
Among the many memorable things Freeman Dyson has said in a lifetime of research, one that stands out for me is relatively recent. “Look for what is detectable, not for what is probable.” This was Dyson speaking at a TED conference in Monterey, CA back in 2003, making the point that the universe continually surprises us, and by making too many assumptions about what we are looking for, we may miss unexpected things that can advance our understanding. Dyson has been thinking about this for a long time considering that it was way back in 1960 that he first suggested looking for the excess infrared radiation that might flag a distant Dyson sphere. I would call this an unorthodox approach to SETI in its day except that when he first came up with it, Dyson didn’t have a SETI effort to consider. It was only in the same year that Cornell’s Frank Drake began SETI observations at Green Bank, and a scant year before that that Philip Morrison and Giuseppe Cocconi published the seminal paper...
Interstellar Ice Grains and Life’s Precursors
One of the first science fiction novels I ever read was The Black Cloud, by astrophysicist Fred Hoyle. I remember that one of my classmates had smuggled it into our grade school and soon we were passing it around covertly instead of reading whatever it was we had been assigned. In Hoyle's novel, scientists discover that the cloud, which approaches the Solar System and decelerates, may be a life-form with which they can communicate. My young self was utterly absorbed by this book and I suspect it will hold up well to re-reading. What brings The Black Cloud to mind is recent work using data from the Green Bank Telescope in West Virginia, where scientists have been studying an enormous gas cloud some 25,000 light years from Earth near the center of the Milky Way in the star forming region Sagittarius B2(N). This cloud is not, of course, behaving as entertainingly as Hoyle's, but it's offering up information about how interstellar molecules that are intermediate steps toward the final...
Interstellar Expansion: Colonizing Ice Dwarfs
Are habitable planets the best places to look for life? The question seems odd, because we're assuming life has to have clement conditions to emerge and survive. But step beyond the question of life's formation and the issue can be framed differently. Where beyond its birthplace might life migrate? In SETI terms, where might we look for the signature of a civilization advanced enough to move beyond its home world and expand between the stars? A lot of ideas seem to be converging here. In Huntsville, Ken Roy (whose description at the recent interstellar conference was 'an engineer living and working amidst the relics of the Manhattan Project in Oak Ridge, Tennessee') described potential habitats stretching far out into the Solar System and beyond. Roy has been working for some time with Robert Kennedy and David Fields on colonization scenarios. My own talk covered the kind of places where we might extract resources, ranging from icy dwarfs like Pluto to cometary objects and 'rogue'...