Centauri Dreams regular James Jason Wentworth wrote recently with some musings about Bracewell probes, proposed by Ronald Bracewell in a 1960 paper. Bracewell conceived the idea of autonomous craft that could monitor developments in a distant solar system, perhaps communicating with any local species that developed technology. Pondering how such a craft might manage station-keeping over the aeons, Jason hit on the idea of using a natural effect that would draw little attention to itself, one he explains below. An amateur astronomer and interstellar travel enthusiast who worked at the Miami Space Transit Planetarium and volunteered at the Weintraub Observatory atop the adjacent Miami Museum of Science, Jason now makes his home in Fairbanks (AK). He was the historian for the Poker Flat Research Range sounding rocket launch facility near Fairbanks. His space history and advocacy articles have appeared in Quest: The History of Spaceflight magazine and Space News. by James Jason Wentworth...

Lunar Mission One is an interesting private attempt to put a payload on the lunar surface, a crowdsourced project aimed at doing good science and deepening public participation in spaceflight. Remembering the Apollo days, I'm always interested in seeing what can be done to renew interest in space, and having the chance to make a contribution toward such a self-starting space mission is undeniably attractive. As witness Lunar Mission One's pitch on Kickstarter, which has aimed for an ambitious £600,000 and has already raised £520,341. That figure is as of this morning, with five days to go in the attempt, and it's clear enough that £600,000 won't buy a lunar mission of considerable complexity, as this one is. But it's enough to take an effort that has been seven years in the building to the next level, which means establishment of working management teams and the beginning of procurement planning and risk assessment. That turns what has been a part-time volunteer project into a...

Some final thoughts on hybrid propulsion will wrap up this series on solar sails, which grew out of ideas I encountered in the new edition of the Matloff, Johnson and Vulpetti book Solar Sails: A Novel Approach to Interplanetary Travel (Copernicus, 2014). The chance to preview the book (publication is slated for later this month) took me in directions I hadn't anticipated. Solar Sails offers a broad popular treatment of all the sail categories and their history, as you'd expect, but this time through I focused on its four technical chapters on sail theory that helped me review the details. And because I kept running into the idea of multiple modes of propulsion, my thoughts on avoiding doctrinaire solutions continue to grow. In fact, I'd venture to say that probing into the possibilities of multimodal propulsion may offer a serious opportunity for insights. Centauri Dreams regular Alex Tolley came up with one of these yesterday, asking whether a sail mission to Jupiter space might...

What can we do to make telescopes better both on Earth and in space? Ashley Baldwin has some thoughts on the matter, with reference to a new paper that explores interferometry and advocates an approach that can drastically improve its uses at optical wavelengths. Baldwin, a regular Centauri Dreams commenter, is a consultant psychiatrist at the 5 Boroughs Partnership NHS Trust in Warrington, UK and a former lecturer at Liverpool and Manchester Universities. He is also a seriously equipped amateur astronomer -- one who lives a tempting 30 minutes from the Jodrell Bank radio telescope -- with a keen interest in astrophysics and astronomical imaging. His extensive reading takes in the latest papers describing optical breakthroughs, making him a key information source on these matters. His latest find could have major ramifications for exoplanet detection and characterization. by Ashley Baldwin An innocuous looking article by Michael J. Ireland (Australian National University, Canberra)...

I've mentioned before the irony that we may discover signs of robust extraterrestrial life sooner around a distant exoplanet than right here in our own Solar System. The scenario isn't terribly implausible: Perhaps we come up empty on Mars, or find ourselves bogged down with ambiguous results. As our rovers dig, we still have Europa, Enceladus and other outer system possibilities, but probably face a wait of decades before we could build and fly the missions needed to identify life. Meanwhile, the exoplanet hunt continues. While we've had many a setback -- the Space Interferometry Mission will always stand out in this regard, not to mention the inability to follow through with Terrestrial Planet Finder, Darwin and other high-end concepts -- it's just possible that within the next few decades, a space-based observatory will detect a solid biosignature from an exoplanet's atmosphere. Even the James Webb Space Telescope should be able to detect the transmission spectrum of an...

Adam Crowl first appeared in Centauri Dreams not long after I opened the site to comments about nine years ago. His insights immediately caught my eye and challenged my thinking. I have always admired auto-didacts, and Adam is an outstanding example: "I don't work in this field nor did I especially train in it," he writes. "I did physics/maths/engineering study but my astrophysics, astrodynamics, planetology and interstellar propulsion knowledge is self-taught." The list of books in the various disciplines -- as well as science fiction -- by which he did this will, I hope, become a future Centauri Dreams article. Adam writes the Crowlspace blog, is active in Project Icarus, the re-design of the 1970's Project Daedalus fusion starship now in progress at Icarus Interstellar, and is a frequent participant on this site, often pointing me to papers I would otherwise have missed. The one he discusses today is, typically for Adam, a true mind-bender. by Adam Crowl The long-term fate of Life...

We have another 'habitable zone' planet to talk about today, one not much bigger than the Earth, but it's probably also time to renew the caveat that using the word 'habitable' carries with it no guarantees. The working definition of habitable zone right now is that orbital distance within which liquid water might exist on the surface of a planet. Whether it actually does is just one of the questions. A second is whether or not we're in fact dealing with a rocky terrestrial world. So Centauri Dreams approaches the announcement of Kepler-186f with guarded enthusiasm for an exoplanet that looks interesting indeed. Five planets circle this star, an M-dwarf a great deal smaller and cooler than the Sun. Discovered by the Kepler space observatory, the planet presents us with transit information telling us that it is about 1.1 Earth radii, although we don't yet know what the mass of this world is, and hence can't make a definitive call on whether or not it is rocky. But Stephen Kane (San...

Reading Charles Adler's Wizards, Aliens and Starships over the weekend, I've been thinking about starflight and cost. Subtitled 'Physics and Math in Fantasy and Science Fiction,' Adler's book uses the genres as a way into sound science, and his chapters contain numerous references to writers like Poul Anderson, Larry Niven and Robert Heinlein. On the matter of speculative propulsion systems, he lingers over fusion and describes the work of Project Daedalus back in the 1970s, when an ad hoc team of volunteer scientists and engineers put together a serious starship study. Like the vessels written about in the science fiction of that era and before, Daedalus was simply a mammoth craft -- 53 million kilograms! -- but that corresponded with what SF had been telling us all along. We would travel to the stars aboard vessels not so different from ocean liners, perhaps big enough to be livable on a daily basis, or at least big enough to pack thousands of humans into cryogenic containers for a...

Most Centauri Dreams readers are hardly going to be surprised by the idea that a large number of objects exist well outside the orbit of Pluto and, indeed, outside the Kuiper Belt itself. The search for unknown planets or even a brown dwarf that might perturb cometary orbits in the Oort Cloud has occupied us for some time, with the latest analysis of WISE findings showing that nothing larger than Jupiter exists out to a distance of 26,000 AU. Objects of Saturn size or larger are ruled out within 10,000 AU, according to the work of Kevin Luhman (Penn State) and team, whose study probed deeply into the Wide-field Infrared Survey Explorer's results. For more on all this, see WISE: New Stars and Brown Dwarfs. But the evidence for objects big enough to perturb the local neighborhood does persist, even if we have to scale down our expectations as to its size. A new paper in Nature reports the discovery of 2012 VP113, a dwarf planet that joins Sedna in orbiting entirely beyond the Kuiper...

Yesterday I wrote about what Michael Michaud calls 'the new cosmic humanism,' looking back at an essay the writer and diplomat wrote for Interdisciplinary Science Reviews in 1979. Intelligence, Michaud believes, creates the opportunity to reverse entropy at least on the local scale, and to impose choice on a universe whose purpose we do not otherwise understand. Continuing growth into space, expansion and discovery are the kind of long-term goals humans can share, highlighting the extension of knowledge and the rediversification of our species. What Michaud is talking about is nothing less than a mission statement for extraterrestrial man, one that trades off a key uncertainty: In the face of an indifferent universe, intelligence itself may prove to be an evolutionary quirk that is of little consequence. Whether or not this is the case could depend on the decisions and purposeful choices of intelligent beings, assuming they choose to expand into the cosmos. Let me quote Michaud on...

An assistant professor of astronomy and astrophysics at Penn State, Jason Wright is well known to the Centauri Dreams community because of his continuing work on the search for extraterrestrial intelligence through detection of its waste heat rather than directed communication. The discipline widely known as Dysonian SETI is receiving more and more attention, and given Dr. Wright’s prominence in the field, I was delighted to receive the essay below, which offers background on the subject at large and an overview of his current project. Dr. Wright is a member of the Center for Exoplanets and Habitable Worlds and the Penn State Astrobiology Research Center (part of the NASA Astrobiology Institute), as well as being a member of the California Planet Survey consortium. His AstroWright blog is essential reading for anyone interested in SETI and the process of science at work. He also maintains the Exoplanet Orbit Database and Exoplanet Data Explorer at exoplanets.org. by Jason T. Wright...

Search for one thing and you may run into something just as interesting in another direction. That has been true in the study of exoplanets for some time now, where surprises are the order of the day. Today David Kipping (Harvard-Smithsonian Center for Astrophysics) addressed the 223rd meeting of the American Astronomical Society in Washington to reveal a planetary discovery made during the course of a hunt for exomoons, satellites of planets around other stars. Kipping's team has uncovered the first Earth-mass planet that transits its host star. Just how that happened is a tale in itself. Kipping heads up the Hunt for Exomoons with Kepler project, which mines the Kepler data looking for tiny but characteristic signatures. Transit timing variations are the key here, for a planet with a large moon may show telltale changes in its transits that point to the presence of the orbiting body. In the case of the red dwarf KOI-314, it became clear Kepler was seeing two planets repeatedly...

When technologies converge from rapidly fermenting disciplines like biology, information science and nanotech, the results become hard to predict. Singularities can emerge that create outcomes we cannot always anticipate. Rachel Armstrong explores this phenomenon in today's essay, a look at emerging meta-technologies that are themselves life-like in their workings. The prospects for new forms of design in our living spaces, including future spacecraft environments, are profound, as ongoing work in various venues shows. Dr. Armstrong, a regular Centauri Dreams contributor, explores these issues through her work at AVATAR (Advanced Virtual and Technological Architectural Research) at the University of Greenwich, London. by Rachel Armstrong Three lumps of muck hit the breathing membrane. A scattering of fragments blew back at the boys as they shattered like crumbs. 'You're right! They disappeared!' crowed the smallest of the trio. 'That building literally - ate dirt!' Despite its lumpy...

by Stephen Ashworth Being a jazz buff (the 1950s and early 1960s are my era of choice) I naturally note that frequent Centauri Dreams commenter and contributor Stephen Ashworth is a tenor sax man who regularly plays in venues near and around Oxford in the UK. Stephen is also, of course, an insightful writer on matters touching our future in space, not only through his work in the Journal of the British Interplanetary Society but also in his Astronautical Evolution site, which bills itself as studying “The social and political basis for the optimistic, progressive, astronautical society of the present and future.” In this essay, Stephen looks at ways of viewing extraterrestrial intelligence that pose different models for the emergence and spread of life in the universe. NOTE: If you'd like to comment, be aware that today is a travel day for me, so comment moderation will be sporadic, but I'll catch things up tonight. Speculations about the existence of extraterrestrial civilisations...

As we saw last week, touching down on Europa is going to be a tricky maneuver, at least based on the surface mapping we have so far, where boulders show up all the way down to the limits of resolution. That's why we need better imagery from the moon, a major motivation for the proposed Europa Clipper. Titan poses far fewer problems. Its thick atmosphere allowed the Huygens probe to land softly after a long, slow descent by parachute. Proposals for Titan missions have included boats to explore its lakes (Titan Mare Explorer) and airborne laboratories to soar through its skies (AVIATR: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance). The SETI Institute, working with NASA, has been testing the lake option at Laguna Negra, a lake in the Chilean Andes, in a project called Planetary Lake Lander (PLL). The idea is to develop the kind of autonomous hardware we'll need to explore Titan from the surface. But PLL is a dual-purpose mission that also studies the watershed of Chile's...

What kind of assumptions do we bring to SETI, and how are those assumptions changing? Tau Zero's Larry Klaes has some thoughts on that, along with suggestions about what a new book on the subject may want to include in its second edition. By Larry Klaes SETI, the Search for Extraterrestrial Intelligence, has traditionally operated on the premise that there may be beings in the Milky Way galaxy and beyond who are smart, aware, and interested enough to deliberately attempt to contact other similarly advanced societies in the Universe. The primary purpose for such an effort would be to alert any potential celestial neighbors to their presence for the exchange of information and ideas about themselves, their home world, and their take on existence. Their methods of transmission would include certain forms of electromagnetic radiation which the various parties should have in common, such as radio and light waves. This Messaging to Extraterrestrial Intelligences, or METI, is considered to...

Red dwarfs or brown? The question relates to finding targets as the James Webb Space Telescope gets closer to launch. We're going to want to have a well defined target list so that the JWST can be put to work right away, and part of that effort means finding candidate planets the telescope can probe. Yesterday's white paper on a proposed search for brown dwarfs using the Spitzer Space Telescope lined up a number of reasons why these objects are good choices: * for a given planetary equilibrium temperature, the orbit gets shorter with decreasing primary mass, increasing the probability of transit and providing 50+ occultations per year (and 50+ transits); * the planet to brown dwarf size ratio means transiting rocky planets produce deep transits and permit the detection of planets down to Mars' size in a single transit event when using Spitzer; * the reliability of the detection is helped by the absence of known false astrophysical positives: brown dwarfs have very peculiar colors,...

At the top of my list of people I'd someday like to have a long conversation with is Nick Bostrom, a philosopher and director of Oxford's Future of Humanity Institute. As Centauri Dreams readers will likely know, Bostrom has been thinking about the issue of human extinction for a long time, his ideas playing interestingly against questions not only about our own past but about our future possibilities if we can leave the Solar System. And as Ross Andersen demonstrates in Omens, a superb feature on Bostrom's ideas in Aeon Magazine, this is one philosopher whose notions may make even the most optimistic futurist think twice. I suppose there is such a thing as a 'philosophical mind.' How else to explain someone who, at the age of 16, runs across an anthology of 19th Century German philosophy and finds himself utterly at home in the world of Schopenhauer and Nietzsche? Not one but three undergraduate degrees at the University of Gothenburg in Sweden followed. Now Bostrom applies his...

Michael Michaud wrote the essay that follows back in 1978 for a now-defunct magazine that never published it. In recent correspondence about Daedalus designer Alan Bond, Michael referred to the essay and I asked him to forward a copy, which had also passed through the hands of Freeman Dyson and Bob Forward not long after he wrote it. Although it is dated, Starships of the Mind does a wonderful job presenting the major interstellar propulsion ideas, leavened with Michael's innate optimism, which has inspired me for many years. It's a bit of starship history that deserves to be in circulation, and Michael was kind enough to agree. Many thanks are owed as well to my friend David Warlick, who scanned the original and, through the wonders of optical character recognition, rendered it into digital form. Centauri Dreams readers will know Michael Michaud as the author of Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials (Springer, 2007), an essential...