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A Closer Look at Proxima b

by Paul Gilster | Aug 31, 2016 | Exoplanetary Science | 78 Comments

I have much more to say about the Breakthrough Starshot meetings, but last evening I decided to slow the pace a bit. I mentioned in my first report that the discovery of a planet around Proxima Centauri had woven through our San Francisco meetings, creating a bright thread of discussion that continued through all three days. We are also getting papers on Proxima’s planet that inform us more about its potential habitability. In the next couple of days, then, I want to go through some of these before returning soon to the broader issues of Starshot. I also have to admit that I am still transcribing some of my handwritten notes from San Francisco to get everything in synch with my laptop, a process that is taking longer than I intended, thanks to my murky handwriting... In any case, whether Proxima b is habitable or not would surely play a large role in any decisions about using it as Starshot’s initial target. So let’s remember what Guillem Anglada-Escudé and the Pale Red Dot team had...

Breakthrough Starshot Report 2: Drilling Down to the Basics

by Paul Gilster | Aug 30, 2016 | Missions | 36 Comments

A lot of things can go wrong when you're working on a thirty-year project. Consider the charter of the systems subcommittee of Breakthrough Starshot, whose mission is to "...ensure that Starshot engineering activities can and will result in a 0.2c mission to Alpha Centauri." In the hands of the capable Kevin Parkin, the subcommittee has oversight over a systems team that will conduct system engineering, modeling and integration activities. I call Parkin 'capable' but, like so many of the people I dealt with at the recent meetings in San Francisco, he strikes me as flat-out brilliant. He's also a strategic thinker who knows how to communicate. Parkin's presentation on how to structure a project as complex as Starshot included classic failure modes of past projects, such as team members working with differing assumptions, a focus on details and not on the whole, and a focus on the whole and not on the details. Any one of these can trip you up. Walk a fine line, in other words, and try...

At the Breakthrough Starshot Meetings

by Paul Gilster | Aug 29, 2016 | Missions | 52 Comments

An interesting typo -- I had started to write 'On the plane back from Proxima b,' still a bit groggy from lack of morning coffee. Let's correct that to 'On the plane back from San Francisco.' I was coming back from the Breakthrough Starshot meetings, most of which took place at Moffett Field, a former naval air station that NASA owns through its adjacent Ames Research Center. Presume no NASA involvement, though -- Moffett Field is used by many and includes three university branch campuses as well as the building leased by Breakthrough Starshot. My plan had been to settle in on the plane with my notes as I worked out what to say about the trip. Instead, I succumbed to sleep for a good part of the journey. I had slept well each night, but the meetings were intense and the note-taking non-stop. I arrived two hours after the first of them began in a small boardroom, wedged myself into a chair in the corner after nodding hello to a number of familiar faces, and began taking notes by hand,...

An Interesting SETI Candidate in Hercules

by Paul Gilster | Aug 27, 2016 | Astrobiology and SETI | 563 Comments

A candidate signal for SETI is a welcome sign that our efforts in that direction may one day pay off. An international team of researchers has announced the detection of "a strong signal in the direction of HD164595" in a document now being circulated through contact person Alexander Panov. The detection was made with the RATAN-600 radio telescope in Zelenchukskaya, in the Karachay-Cherkess Republic of Russia, not far from the border with Georgia in the Caucasus. The signal was received on May 15, 2015, 18:01:15.65 (sidereal time), at a wavelength of 2.7 cm. The estimated amplitude of the signal is 750 mJy. No one is claiming that this is the work of an extraterrestrial civilization, but it is certainly worth further study. Working out the strength of the signal, the researchers say that if it came from an isotropic beacon, it would be of a power possible only for a Kardashev Type II civilization. If it were a narrow beam signal focused on our Solar System, it would be of a power...

Proxima Centauri Planet

by Paul Gilster | Aug 24, 2016 | Exoplanetary Science | 216 Comments

A planet in the habitable zone around Proxima Centauri? The prospect dazzles the imagination, but then, I’ve been thinking about just that kind of planet for most of my life. Proxima Centauri is, after all, the closest star to our own, about 15000 AU from the primary Alpha Centauri stars (though thought to be moving with that system). A dim red dwarf, Proxima wasn’t discovered until 1915, but it quickly seized the imagination of science fiction writers who pondered what might exist around such a star. Murray Leinster’s story “Proxima Centauri” (1935) is a clanking, thudding tale but it still evokes a bit of the magic of one of the earliest fictional interstellar voyages. Image: This wide-field image shows the Milky Way stretching across the southern sky. The beautiful Carina Nebula (NGC 3372) is seen at the right of the image glowing in red. It is within this spiral arm of our Milky Way that the bright star cluster NGC 3603 resides. At the centre of the image is the constellation of...

Breakthrough Starshot Meetings

by Paul Gilster | Aug 23, 2016 | Administrative | 30 Comments

I'm at the Breakthrough Starshot meetings in San Francisco, with a full schedule indeed. As I did last time in Palo Alto, I won't try to post daily because there just won't be time, and in any case, I will need to go over my notes and consolidate my impressions. Even so, I plan to slip something interesting in here in the near future (keep an eye on Wednesday afternoon EDT), and will try to keep comment moderation active, though probably on a more infrequent basis than usual. Next week I'll report in on what happened at the committee level at Breakthrough Starshot.

The Blue Spectres of Abyssal Europa

by Paul Gilster | Aug 19, 2016 | Astrobiology and SETI | 68 Comments

Claudio Flores Martinez has just finished an MSc at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany and is now enroute to a PhD in theoretical biology. He currently serves as a research assistant at the Developmental Biology Unit of EMBL and the University of Heidelberg's Centre for Organismal Studies. With three papers in Acta Astronautica under his belt, Claudio is already deep into theoretical evolutionary biology, and in particular the contingency vs. convergence debate. In the paper below, he discusses how these issues couple with the possible emergence and development of life on Europa and the potential biosignatures by which we might find it, a journey that takes us deep into the nature of living systems. Just what might we encounter under that Europan ice? by Claudio Flores Martinez “Science is an endless search for truth. Any representation of reality we develop can be only partial. There is no finality, sometimes no single best representation. There...

Getting Ready for OSIRIS-REx

by Paul Gilster | Aug 18, 2016 | Asteroid and Comet Deflection | 9 Comments

Back in the 1930s, the German astronomer Karl Reinmuth discovered a near-Earth asteroid now called 1862 Apollo, which gave its name to the Apollo asteroids, all of them Earth-crossing and of high interest to those looking to plan asteroid missions. The number of known Apollo asteroids totals close to 7000. The one that gains our attention today is 101955 Bennu, for this is the target of the upcoming OSIRIS-REx mission, scheduled for launch on September 8. Standing for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, OSIRIS-REx is a sample return mission that will, if all goes well, reach Bennu in 2018, surveying the asteroid from nearby space for 505 days in search of optimum sampling sites. The plan is for no actual landing but a very close approach in which the spacecraft's extended robotic arm will attempt to gather the sample. The robotic arm (known as TAGSAM, for Touch-And-Go Sample Acquisition Mechanism) will collect between 60 and 2,000...

A Near-Term Commercial Asteroid Mining Mission

by Paul Gilster | Aug 17, 2016 | Asteroid and Comet Deflection | 33 Comments

Most readers will recall the Spacecoach, developed by Brian McConnell and Alex Tolley and widely discussed in these pages. A workhorse spacecraft designed to shuttle crew and cargo between Earth and nearby planets, the Spacecoach was presented as a way to open up regular commercial use of the Solar System, on the pattern of the stagecoaches that connected towns in the American Old West. One of the many beauties of the Spacecoach was the idea of using reclaimed water and waste gases as a propellant in its electric engines. With water as a propellant, the mass of the system can be sharply reduced, with an associated reduction in mission costs. Benefits like that don't stay hidden for long, and I see that Deep Space Industries is likewise attracted to water in the design of its new engine. The Prospector-1 spacecraft, slated for launch by the end of the decade, uses a system DSI calls 'Comet.' It expels superheated water to create thrust, a useful idea given the company's intentions....

Brown Dwarf Analysis Offers Exoplanet Implications

by Paul Gilster | Aug 16, 2016 | Deep Sky Astronomy & Telescopes | 13 Comments

Brown dwarfs offer exciting prospects for exoplanet work. Not only are we learning that they can have planets of their own, but brown dwarfs themselves are a useful bridge between planets and stars. We also know that there are a lot of them out there. According to data from the WISE (Wide-field Infrared Survey Explorer) mission, there is about one brown dwarf for every six main sequence stars. That’s plenty of brown dwarfs, but it actually represents a reduction in estimates, which once went as high as a brown dwarf for every star. Moreover, WISE could identify about 200 brown dwarfs relatively near the Sun, with 33 within 26 light years. 211 stars are found in that same volume, incidentally. If we extrapolate this out to the galaxy at large, we should have about 33 billion brown dwarfs, assuming a galactic total of 200 billion stars. These numbers have a certain flexibility in them, especially given how hard it can be to track the coolest Y-dwarfs. Added to this is the fact that...

Niku: A ‘Rebellious’ Trans-Neptunian Object

by Paul Gilster | Aug 15, 2016 | Outer Solar System | 14 Comments

We’ve all come to terms with the fact that beyond the orbit of Neptune there exists a large number of objects. These trans-Neptunian objects (TNOs) substantially altered the almost sedate view of the Solar System that prevailed in the first half of the 20th Century, showing us that far from being a tame and orderly place of planets, asteroids and comets, we were in a system filled with material left over the the system’s formation. Tame and orderly became ragged and unkempt, and it was clear that the outer system was a place ripe for discovery. Pluto was the first TNO to be discovered, all the way back in 1930, but the modern era of trans-Neptunian objects began in 1992 with the discovery of (15760) 1992 QB, and we can now count over 1750 TNOs, as listed by the Minor Planet Center. Bear in mind that we can divide the entire space occupied by TNOs into several prominent divisions: the Kuiper Belt, the Oort Cloud, and the scattered disk, with a few outliers like Sedna causing...

Evening Landscape with Exomoons

by Paul Gilster | Aug 12, 2016 | Exoplanetary Science | 20 Comments

I often work out my thoughts on the topics we discuss here while taking long walks. I try to get in five miles a day but more often it’s about three. In any case, these long, reflective walks identify me as the neighborhood eccentric, an identity that is confirmed by the things I write about. What’s interesting about that is that so many people have a genuine interest in the stars and how we might get there. Some of the best questions I’ve ever had have been from people whose interest is casual but persistent, and one good question usually leads to another. Hence I wasn’t surprised on yesterday's walk to find myself talking with a neighbor about exomoons and why we study them. After all, we have a Solar System in which moons are commonplace. Isn’t it perfectly obvious that different solar systems would have planets with moons? The answer is yes, but it also follows that things that seem perfectly obvious still have to be confirmed. But let’s unpack it a bit more than that. We’re...

Liquid Methane in Titan’s Canyons

by Paul Gilster | Aug 11, 2016 | Outer Solar System | 9 Comments

It was in 2012 that Cassini data showed us the presence of the river system now called Vid Flumina, which empties into Titan's Ligeia Mare after a journey of more than 400 kilometers. Given surface temperatures on this largest of Saturn's moons, researchers assumed liquid methane would be the key player here. The question was whether the river -- and the eight canyons that branched off from it along its course -- were still filled with liquid or long dry. Now we have the answer, thanks to new work from Valerio Poggiali (La Sapienza University, Rome) and colleagues. Using radar signals bounced off Titan's surface in May of 2013, the researchers probed the deep gorges near Titan's north pole and were able to distinguish rocky material from smooth liquid. We're clearly looking at a surface that is actively eroding, one with striking comparisons to the landscapes of Utah and Arizona as well as the Nile River gorge. Key to the work here is the use of Cassini's radar as an altimeter,...

Stromatolites: Astrobiological Implications

by Paul Gilster | Aug 10, 2016 | Astrobiology and SETI | 18 Comments

Oil companies involved in astrobiology? It doesn't seem likely, but in a roundabout way, it's true. A consortium including Chevron, Repsol, BP and Shell have a natural interest in developing better models for subsurface reservoirs and source rocks in microbe-rich carbonate environments. At the same time, NASA's Astrobiology Program is intrigued with how we could find bacterial structures on other worlds, and their role in planetary habitability. The result: Both Big Oil and NASA are supporting research into stromatolites, the calcium-carbonate rock structures built up by lime-secreting bacteria (technically, cyanobacteria, that draw their energy from photosynthesis). We can probe ancient life on Earth by studying these accreted structures, some of which go back more than 3.5 billion years. Erica Suosaari works for Bush Heritage Australia, an organization involved in conservation and land management. The Hamelin Station Reserve in Western Australia borders a nature reserve with vast...

Atmospheric Collapse on Io

by Paul Gilster | Aug 9, 2016 | Outer Solar System | 9 Comments

I suspect most scientists would like to have a moment like the one Stanton Peale, Patrick Cassen and Ray Reynolds experienced when Voyager flew past Io in 1979. How many of us get to see a major idea vindicated in such short order? It was on March 5 that Voyager 1 passed within 22,000 kilometers of Io. A scant three days before, Peale, Cassen and Reynolds had published their prediction that tidal forces should keep the moon's interior roiling, resulting in volcanic activity. Linda Morabito, on the Voyager navigation team, analyzed Voyager imagery shortly thereafter to discover that volcanoes were indeed active on the surface. What a triumph for the power of thorough analysis and prediction. Voyager, in fact, found nine plumes on Io, while demonstrating that its surface was dominated by sulfur and sulfur dioxide frost, with extensive lava fields extending for hundred of kilometers. The moon was also observed to have a thin atmosphere consisting primarily of sulfur dioxide. That thin...

SETI, Astrobiology and Red Dwarfs

by Paul Gilster | Aug 8, 2016 | Astrobiology and SETI | 69 Comments

If you’ve been following the KIC 8462852 story, you’ll want to be aware of Paul Carr’s Dream of the Open Channel blog, as well as his Wow! Signal Podcast, both of which make for absorbing conversation. In his latest blog post, Carr offers sensible advice about how to look at anomalies in our astronomical data. Dysonian SETI tries to spot such anomalies in hopes of uncovering the activities of an extraterrestrial civilization, but as Carr makes clear, this is an enterprise that needs to be slowly and patiently done, without jumping to any unwarranted assumptions. Let me quote Carr on this important point: ...we will have to be patient, since we will be almost certainly be wrong at first, or perhaps just unlucky in our search. We don't need to nail it exactly, but we will need to develop rough models of ET activity that distinguishes it from nature. These models would more or less fit the data that we think anomalous, would make testable predictions, and would show how to rule out at...

KIC 8462852: Fading in the Kepler Data

by Paul Gilster | Aug 5, 2016 | Deep Sky Astronomy & Telescopes | 127 Comments

Those of you who have been following the controversy over the dimming of KIC 8462852 (Tabby's Star) may remember an interesting note at the end of Bradley Schaefer's last post on Centauri Dreams. Schaefer (Louisiana State University) had gone through his reasoning for finding a long-term dimming of the star in the DASCH (Digital Access to a Sky Century@Harvard) database. His third point about the star had to do with the work of Ben Montet (Caltech) and Joshua Simon (Carnegie Observatories). Montet and Simon's work relied on an interesting premise. Tabby's Star had been discovered because it was in the Kepler field, and thus we had high-quality data on its behavior, the unusual light curves that the Planet Hunters team brought to the attention of Tabetha Boyajian. As the researchers note in a new paper, Kepler found ten significant dips in the light curve over the timespan of the Kepler mission, dips that were not only aperiodic but irregular in shape, and that varied enormously, from...

Antimatter Acquisition: Harvesting in Space

by Paul Gilster | Aug 3, 2016 | Antimatter | 32 Comments

Talking about antimatter, as we've done in the past two posts, leads to the question of why the stuff is so hard to find. When we make it on Earth, we do so by smashing protons into targets inside particle accelerators of the kind found at the Fermi National Accelerator Laboratory in Batavia, IL and CERN (the European Organization for Nuclear Research). It's not exactly an efficient process from the antimatter production standpoint, as it produces a zoo of particles, anti-particles, x-rays and gamma rays, but it does give us enough antimatter to study. But there is another way to find antimatter, for it occurs naturally in the outer Solar System and even closer to home. James Bickford (Draper Laboratory, Cambridge MA) has looked at how we might trap antimatter that occurs in the Earth's radiation belts. In a report for NIAC back in 2006 (available here), Bickford laid out a strategy for using high temperature superconductors to form two pairs of RF coils with a radius of 100 meters,...

The Evolution of Antimatter Propulsion

by Paul Gilster | Aug 2, 2016 | Advanced Rocketry | 14 Comments

Thinking about Eugen Sänger's photon rocket concept inevitably calls to mind his Silbervogel design. The 'Silverbird' had nothing to do with antimatter but was a demonstration of the immense imaginative power of this man, who envisioned a bomber that would be launched by a rocket-powered sled into a sub-orbital trajectory. There it would skip off the upper atmosphere enroute to its target. The Silbervogel project was cancelled by the German government in 1942, but if you want to see a vividly realized alternate world where it flew, have a look at Allen Steele's 2014 novel V-S Day, a page-turner if there ever was one. I almost said that it was a shame we don't have a fictionalized version of the photon rocket, but as we saw yesterday, there were powerful reasons why the design wouldn't work, even if we could somehow ramp up antimatter production to fantastic levels (by today's standards) and store and manipulate it efficiently. Energetic gamma rays could not be directed into an...

Antimatter Propulsion: Birth of a Concept

by Paul Gilster | Aug 1, 2016 | Antimatter | 31 Comments

I spent this past weekend poking into antimatter propulsion concepts and in particular looking back at how the idea developed. Two scientists -- Les Shepherd and Eugen Sänger -- immediately came to mind. I don't know when Sänger, an Austrian rocket designer who did most of his work in Germany, conceived the idea he would refer to as a 'photon rocket,' but he was writing about it by the early 1950s, just as Shepherd was discussing interstellar flight in the pages of the Journal of the British Interplanetary Society. A few thoughts: Sänger talked about antimatter propulsion at the 4th International Astronautical Congress, which took place in Zurich in 1953. I don't have a copy of this presentation, though I know it's available in a book called Space-Flight Problems (1953), which was published by the Swiss Astronautical Society and bills itself as a complete collection of all the lectures delivered that year in Zurich. If you like to track ideas as much as I do, you'll possibly be...

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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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