Kepler-78b: Rocky World in Unusual Orbit

When I was first learning about astronomy by reading every book I could find on the subject -- I spent a lot of time at the library in my youth -- I was fascinated to hear stories of a planet closer to the Sun than Mercury. The French scientist Urbain Le Verrier pondered the existence of such a world in the 19th Century, wondering if it wouldn't explain peculiarities in Mercury's orbit. When an amateur astronomer named Edmond Modeste Lescarbault claimed he had observed a transit of such a planet in 1859, Le Verrier's investigation satisfied him that the detection was legitimate. He went on to announce the discovery of the planet he dubbed Vulcan in Paris in 1860. Despite a string of other observing claims later in the century, the existence of Vulcan is now discounted, although the possibility of asteroids in tight solar orbits hasn't been ruled out. As for Mercury, it fell to Einstein to demonstrate that apparent anomalies in its orbit could be explained by his theory of General...

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HD 21997: Challenge to Planet Formation Theories

HD 21997 is a star in the southern constellation Fornax (the Furnace) that is yielding some surprising data about how planetary systems form. About 235 light years from Earth, the star is 1.8 times the mass of the Sun and is thought to be about thirty million years old. Observations by an international team using ESA’s Herschel Space Observatory and the Atacama Large Millimeter/sub-millimeter Array (ALMA) in Chile show a ring of material around the star that contains not only a good deal of gas but also the dust produced by the collision of planetesimals. Image: ALMA images of the disk around HD 21997. The left image shows the emission of cold dust grains, situated in a ring around the central star. The middle image displays the emission from carbon monoxide, and shows that gas can also be found closer to the star than dust. The right image depicts the velocity of the gas. The red-colored parts of the disk move away from us, while the blue-colored parts move towards us, indicating...

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Desert Planets Around Carbon-Rich Stars?

Habitable zones are always controversial. Bring up the classic definition of a zone where liquid water can exist on the surface and you run into queries about places like Europa, far outside the HZ in those terms but perhaps capable of supporting life beneath the ice. For that matter, exotic forms of life cannot be ruled out in settings like Titan, though they would be nothing like what we’re familiar with on Earth. Nonetheless, refining our methods to look for life on planets with liquid water is a rational way to proceed and we’re developing the needed tools. As we wait for those tools to be funded and built -- projects like Terrestrial Planet Finder are on indefinite hold -- we can continue to develop our theoretical models for living planets. On that score, Torrence Johnson (JPL) and colleagues have had interesting things to say lately. Johnson spoke at the American Astronomical Society Division of Planetary Sciences meeting in Denver earlier this month, addressing the question...

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Starship Century Symposium, London

Oxford-based Stephen Ashworth, who attended the recent Starship Century event in London, obviously took copious notes, as reflected in the piece that follows. Ashworth is a Centauri Dreams regular, a writer and musician who, like so many of us on this site, ponders the big questions of our engagement with -- and exploration of -- the universe. Here he reflects on the immense challenge of starflight and lets us know how a number of key players now see it. For more of Stephen's perceptive work, check in regularly at his Astronautical Evolution site. by Stephen Ashworth The new book Starship Century, edited by physicists James and Gregory Benford and with contributions from many active in the interstellar field, takes a broad view of questions of interstellar exploration, the editors told this meeting at the Royal Astronomical Society in London on 21 October 2013. In the first place, why has there been such a surge of interest over the past decade or so, with several new organisations...

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Astrosociology: The Human Dimension of Outer Space

Kathleen Toerpe, PhD, is a social and cultural historian who researches the human dimension of outer space through an emerging field called "astrosociology." She is the Deputy CEO for Public Outreach and Education with the Astrosociology Research Institute, volunteers as a NASA/JPL Solar System Ambassador, is active with the 100 Year Starship initiative to lay the groundwork for future interstellar travel, and provides space outreach consulting through Stellar Outreach, LLC. She also teaches social sciences and courses in critical and creative thinking at Northeast Wisconsin Technical College and has spent her spare time hunting for exoplanets and extraterrestrials as a citizen scientist. She can be found on Twitter at @ktoerpe. by Kathleen Toerpe Study the science of art. Study the art of science. Develop your senses- especially learn how to see. Realize that everything connects to everything else. -- Leonardo da Vinci When da Vinci admonished his students to open their eyes to a...

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Titan’s Northern Lake Country

New views from Cassini are giving us a much better look at Titan's north pole and the seas and lakes that make the region so distinctive. This is particularly interesting because most of the moon's lakes are concentrated at its northern latitudes, a fact that demands an explanation. The new near-infrared images show an area of bright terrain in this northern region that had not been observed before. This news release from the Jet Propulsion Laboratory suggests that the surface thus revealed is unique on Titan. If we can figure out what's going on here, we may have an explanation for the concentration of lakes and seas in these latitudes. Image: The vast hydrocarbon seas and lakes (dark shapes) near the north pole of Saturn's moon Titan sprawl out beneath the watchful eye of NASA's Cassini spacecraft. Scientists are studying images like these for clues about how Titan's hydrocarbon lakes formed. Titan is the only world other than Earth that is known to have stable bodies of liquid on...

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Misaligned Planets and their Implications

The red giant Kepler-56, some 3000 light years from the Sun, is telling us useful things about planetary alignments. The star is somewhat out of synch with the majority of Kepler targets to begin with. Most of these are unevolved stars near the main sequence, which are those most likely to produce systems in which a terrestrial world can be observed. But Kepler-56 has exhausted its hydrogen core and has evolved into a red giant. Two planet candidates have been identified here, orbiting in 10.5 and 21.4 days respectively. In fact, Kepler-56 turns out to be the most evolved star observed by Kepler with more than a single detected planet. I'm drawing this from the work of Daniel Huber (NASA Ames) who, with a large team of collaborators, has been studying an apparent anomaly in the Kepler-56 system: The rotation axis of the star is tilted about 45 degrees to our line of sight. The Kepler-56 result was a surprise, says Huber, "because we already knew about the existence of two planets...

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Laser Technologies for Starflight

How do we go about using photons to accelerate a spacecraft to a substantial percentage of the speed of light? Ten percent of c ought to do -- it gets us to Alpha Centauri with a mission time of 43 years and would allow us to at least send flyby probes into that system, with the promise of larger decelerating probes as new technologies became available. After yesterday's post on Young Bae's photonic thrusters, I went back and read his 2012 paper "Prospective of Photon Propulsion for Interstellar Flight" (reference at the end). 10 percent of lightspeed is indeed the minimum he chooses. It works out to 30,000 kilometers per second. Back in the 1950s, the German scientist Eugen Sänger talked about a 'photon rocket' as a way of reaching the stars, but his design called for annihilating electrons and positrons and using the gamma rays thus produced for thrust. The idea stumbled over the problem of controlling this kind of exhaust stream, for gamma rays penetrate anything we use to contain...

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Laser Travel by Photonic Thruster

A recent article in Popular Mechanics about Young K. Bae's work on laser propulsion is generating some buzz, enough that I went back to look at the 2008 report Bae did for the NASA Institute for Advanced Concepts. Actually there are two reports, a Phase I and a later Phase II (with additional funding) on the topic of "A Contamination-Free Ultrahigh Precision Formation Flight Method Based on Intracavity Photon Thrusters and Tethers." Bae was interested in spacecraft formation flight down to precisions of mere nanometers. The idea relates to missions that would use multiple spacecraft to study astronomical phenomena. In fact, setting up a proper configuration would allow the study of biosignatures in the atmospheres of terrestrial exoplanets, using the technique of interferometry. Here the image produced has a resolution equal to that of a telescope as large as the maximum antenna separation, but the spacecraft involved have to maintain their alignment. Both ESA (with the Darwin...

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The Ethics of Unintended Consequences

Diplomat and author Michael Michaud returns to Centauri Dreams with a look at interstellar probes and how we might use them. Drawn from a presentation originally intended for the 100 Year Starship Symposium in Houston, the essay asks what effect our exploring another stellar system would have on its possible inhabitants. And beyond that, what effect would it have on us, as we weigh ethical issues and ponder the potential -- and dangers -- of highly intelligent artifacts going out into the galaxy? Michaud is the author of the indispensable Contact with Alien Civilizations: Our Hopes and Fears about Encountering Extraterrestrials (Springer, 2007). Among his numerous other works are many on space exploration. He was a U.S. Foreign Service Officer for 32 years, serving as Counselor for Science, Technology and Environment at the U.S. embassies in Paris and Tokyo, and Director of the State Department's Office of Advanced Technology. He has also been chairman of working groups at the...

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White Dwarfs: Evidence for Watery Asteroids

The recent question raised here about conditions on a white dwarf planet provides a segue to the white dwarf GD 61 and the interesting results reported by astronomers at the Universities of Cambridge and Warwick. Relying on data from Hubble as well as Keck I and Keck II and NASA's FUSE telescope, the researchers have analyzed what they believe to be evidence for an asteroid or minor planet that once contained large amounts of water around the star. The water-rich object would have been knocked out of its orbit and subsequently shredded by by the star's gravitational force. Image: Artist impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star GD 61. Similar objects in the Solar System likely delivered the bulk of water on Earth and represent the building blocks of the terrestrial planets. Credit & Copyright: Mark A. Garlick, Space-Art.co.uk/University of Warwick/University of Cambridge. GD 61 is some 150 light years from us, but...

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Origins of Pluto’s Moons

Before getting into the distant regions near Pluto/Charon, let's pause for a moment with a reflection on speed. New Horizons left Earth orbit traveling faster than any other vehicle launched into interplanetary space, although it has since slowed. Now the Juno mission is getting press for its velocity, perhaps impelled by this quote from Bill Knuth (University of Iowa), who is lead investigator for one of the probe's nine scientific instruments. Of Juno's recent close approach to Earth, Knuth says: "Juno will be really smoking as it passes Earth at a speed of about 25 miles per second relative to the Sun. But it will need every bit of this speed to get to Jupiter for its July 4, 2016, capture into polar orbit about Jupiter. The first half of its journey has been simply to set up this gravity assist with Earth." The speed is impressive, about 40 kilometers per second, and far above Voyager 1's 17.1 kilometers per second, as well as New Horizons' expected 14 kilometers per second at...

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Notes & Queries 10/15/13

Starship Century in London A new Starship Century Symposium will be held at the Royal Astronomical Society, Piccadilly, UK on Monday October 21st. If I hadn't exhausted my travel budget by September, I would definitely have this one on my agenda and follow it with a week or so in my favorite city. Here's the information I have on the event from its organizers, James and Gregory Benford: Starship Century addresses the challenges and opportunities for our long-term future in space, with possibilities envisioned by featured speaker Lord Martin Rees, Royal Astronomer, Ian Crawford, Birkbeck College, University of London, writer/scientist Stephen Baxter, James Benford, Microwave Sciences, and Gregory Benford, UC Irvine. Starship Century discusses the implications that these explorations might have upon our development as individuals and as a civilization. Agenda 10 am Starship Century: Toward the Grandest Horizon James & Gregory Benford 10:30 Scientific Benefits of Starships Ian Crawford...

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Arthur C. Clarke: A Life Remembered

Space writer Neil McAleer's long association with Arthur C. Clarke culminated in Visionary: The Odyssey of Arthur C. Clarke (Clarke Project, 2012). A gifted journalist whose work has appeared in numerous magazines and newspapers, McAleer is also the author of The Omni Space Almanac, which won the 1988 Robert S. Ball Award from the Aviation and Space Writers Association. Neil recently reminded me that a new book on Clarke was about to appear, and in the post that follows, he gives us an overview of a title in which Fred Clarke, Arthur's brother, makes an informative contribution, along with a host of writers and other Clarke associates. The photos in Arthur C. Clarke: A Life Remembered are worth the price of admission, and I've reproduced a few of them below with permission. Neil breaks the review down by contributing author and explains what you can expect from each. Ordering information is at the end. by Neil McAleer Arthur C. Clarke: A Life Remembered $22.95 plus shipping. ISBN...

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Black Sky Thinking: The Technology of Nature

A graduate of Cambridge University, Rachel Armstrong completed her clinical training at the John Radcliffe Medical School at the University of Oxford in 1991 and in 2009 embarked on a PhD in chemistry and architecture at University College London. She now serves as co-director of AVATAR (Advanced Virtual and Technological Architectural Research) at the University of Greenwich, London, and as Visiting Research Assistant at the Center for Fundamental Living Technology, Department of Physics and Chemistry, University of Southern Denmark. In this essay, based on a late September presentation at FutureFest in London, Dr. Armstrong recalls the English soothsayer known as 'Mother Shipton' and the petrifying well in Yorkshire that has long been associated with her name. The ensuing thoughts on black sky thinking take us into the realm of 'living architecture' and her engagement with the worldship ambitions of Icarus Interstellar. by Rachel Armstrong "To exist is to change, to change is to...

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Interstellar Wanderers

Because of my fascination with exotic venues for astrobiology, I’ve always enjoyed Karl Schroeder’s novels. The Canadian writer explored brown dwarf planets as future venues for human settlement in Permanence (2002), and in his new book Lockstep (soon to be published by Tor, currently being serialized in Analog), Schroeder looks at ‘rogue’ planets, worlds that move through the galaxy without a central star. Imagine crimson worlds baked by cosmic radiation, their surfaces building up, over the aeons, the rust red complex organic molecules called tholins. Or consider gas giants long ago ejected from the system that gave them birth by close encounters with other worlds. Objects like these and more are surely out there given what we know about gravitational interactions within planetary systems, and they’re probably out there in huge numbers. I’m not going to review how Lockstep uses them just yet -- in any case, I haven’t finished the book -- but we’ll return to its ingenious solution...

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Five Billion Years of Solitude

About a third of the way into his new book Five Billion Years of Solitude: The Search for Life Among the Stars (Current, 2013), Lee Billings describes a time capsule that was sealed in July of 1963 near the Cabrillo Freeway in San Diego, though it has since been moved. Within it was a book that looked a century ahead, with contributions from politicians, astronauts, military figures and others about the world of the future. Copies of the book, titled 2063 A.D. are available, and within them one can find the musings of Nobel-laureate Harold Urey, who worried about our use of energy and noted that largely because of the need for electricity, US fossil fuel consumption had increased eightfold between 1900 and 1955. Was the trend sustainable over the long haul? Urey doubted it, and he was hardly alone, for the need for energy seems to impose sharp limits on what a society can do. Billings notes the work of Tom Murphy (UC San Diego), who works with a long-term 2.3 percent increase in...

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Mars: The Interstellar Connection

Aerospace engineer Gerald W. Driggers embraced the dreams of Dr. Werner von Braun and his team at an early age and was privileged to meet and work with many of them. He was a prominent figure in studies of space colonization and industrialization with Dr. Gerard K. O'Neill in the 1970's and also served as an officer in the US Air Force working on satellite launch vehicles. He has published over 35 technical papers and general interest articles and contributed to three books on technical subjects, but is now turning his attention to science fiction, authoring a series of books called The Earth-Mars Chronicles. Gerald and his wife became the first U.S. sponsors of the Mars One Project, whose objective is to place a team on Mars in 2023. A portion of the proceeds from sales of "The Earth-Mars Chronicles" goes to the Mars One Project. For 17 years, Gerald has lived on a series of boats because, in his words, "It was the closest thing I could get to a space ship." He currently resides in...

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Deep Time, Big History, and Existential Risk

Nick Nielsen thinks big, as his previous work in these pages and elsewhere has shown. His presentation on "The Large Scale Structure of Spacefaring Civilization" at the 2012 100YSS conference examined humanity's growth as defined and enabled by the structure of spacetime itself. His continuing work with Heath Rezabek weighs the factors that threaten a technological civilization, while considering what we can do in response. An author and contributing analyst with strategic consulting firm Wikistrat, Nielsen here looks at our concepts of time and the emergence of 'Big History,' which might be called 'history in a cosmic context.' We are now developing the tools that, used properly, can address and resolve issues of existential risk. by J. N. Nielsen James Hutton is often credited with the origins of the modern conception of geological time, which is sometimes called "deep time." Looking upon the Bass Rock in the outer part of the Firth of Forth James Hutton is said to have remarked,...

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Visualizing Vessel

In his first article for Centauri Dreams, Heath Rezabek described an installation design called Vessel that we might develop to mitigate near and long term risk. The essay explained why we should pursue practical strategies to avoid the permanent stagnation of society in case of catastrophe, and described the need for enduring educational facilities to forestall a flawed realization of our potential over time. The Vessel proposal involves the deliberate engineering of resilient and flexible facilities dedicated to the retention of humanity's legacy as an ongoing hedge against what he calls Xrisk. In this second article, Heath makes a case for the importance of visualization in the early stages of any long term project -- whether terrestrial or beyond -- as a strategy and tool for focusing enthusiasm on the long work of system design. by Heath Rezabek Cory Doctorow, author and open source advocate, has said that if we want to change the future, we need to change the stories people...

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Charter

In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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