by Paul Gilster | Mar 16, 2012 | Sail Concepts |
You wouldn’t think that slowing down a starship would be the subject of a totally engrossing novel, but that’s the plot device in Poul Anderson’s Tau Zero (1970, though based on a 1967 short story called “To Outlive Eternity”). Anderson’s ramscoop starship, the Leonora Christine, can’t slow down because of damage suffered in mid-cruise. Edging ever closer to the speed of light, the crew experiences all sorts of time dilation wonders as they wrestle to regain control, and the ending, while scientifically dubious, is also in every way unforgettable. Anderson could be guilty of over-writing but few writers are gifted with his sheer imaginative sweep.
I’m thinking that coupling a ramscoop with a problem in deceleration is just the ticket for getting into the whole issue of starship arrivals. We can start with Robert Bussard’s 1960 paper “Galactic Matter and Interstellar Spaceflight,” which unwittingly paved the way for the whole magsail concept. Bussard came up with what for a time appeared to be the ultimate in fast transportation, a ramjet that collected interstellar hydrogen in an electromagnetic scoop thousands of kilometers in diameter as it traveled. The collected hydrogen would be used as fuel for the same kind of proton/proton fusion that powers up the Sun. Moreover, this would be an engine that would become more efficient the faster the ship went.
The Ramscoop and the Details
No wonder writers like Anderson and Larry Niven loved the idea, which fed their plots of humanity expanding into the galaxy — even Carl Sagan would point to the Bussard ramjet as a propulsion system that could get us up to a substantial percentage of the speed of light. But in the case of the ramjet, at least one of the devils in the details turned out to be bremsstrahlung radiation, which is produced when charged particles decelerate. Thomas Heppenheimer went to work on this in 1978 and found the Bussard design unworkable because the power that could be produced was dwarfed by the losses from the bremsstrahlung process.
Image: The Bussard ramjet, a concept which may turn out to have more applicability in braking than acceleration. Credit: Adrian Mann.
This wasn’t the end of the ramjet concept because Daniel Whitmire was able to figure out a different way to power up the engine (and in the future we’ll have to talk about Whitmire and his study of the CNO cycle, which makes for a much more powerful and efficient fusion engine), but the most troublesome critique emerged in 1985 through the work of Dana Andrews and Robert Zubrin. Bussard assumed an electromagnetic scoop of vast proportions, but Andrews and Zubrin came to realize that such a scoop produced more drag than it did thrust. In fact, their work showed that when leaving a star system, a ramscoop could serve as an electromagnetic sail. Thus the magsail entered into the lexicon and we began pondering its uses.
If we can’t use Bussard ramjet techniques in cruise, why not use them upon arrival? Switch on the magsail as the vehicle approaches its destination solar system and let it use the star’s stellar wind to brake against. The magsail produces efficient deceleration at high velocities, but an incoming spacecraft could also deploy a conventional solar sail upon arrival for final braking and movement within the planetary system. Magsails could also be used to provide the mission’s initial acceleration, pushed by a particle beam or by a stream of incoming pellets turned into plasma — Gerald Nordley has explored this concept and others germane to our purposes here.
Hybrid Starship Designs
Now we’re talking hybrid approaches to interstellar propulsion. A spacecraft might achieve its initial acceleration, for example, through other forms of fusion, or perhaps through beamed microwave or laser sail technologies, while deploying the magsail for arrival. Get into the details and hybrid systems begin to make sense, because there is nothing that says you have to use the same technologies for interstellar braking as you do for the rest of the journey. But the great problem of deceleration looms over the entire topic of interstellar travel, and it behooves us to think of ways to take advantage of external braking possibilities wherever possible, unless we want to devote most of the bulk of our spacecraft to an onboard deceleration system and its fuel.
I was interested to see that John Mathews considered the deceleration question in his recent paper on self-replicating spacecraft (see Robotic Networks Among the Stars and the subsequent three entries here). Mathews is well acquainted with magsail concepts and advocates braking against the stellar wind, noting that solar sails are efficient only relatively close to the star. Where he moves us a step forward is in his idea of using electrodynamic tether technologies to generate huge amounts of energy from the spacecraft’s movement through the stellar wind, powering the magsail itself and offering options for driving other devices.
The comparison of solar to magnetic sail in terms of decelerating a spacecraft is one we have to get into at more depth, so we’ll continue the deceleration discussion on Monday and most of next week, for it turns out that magsail and solar sail braking are only two of the options we might consider. I want to go through all of these and offer some references for an area of the interstellar conundrum that doesn’t often get the attention it deserves. Project Icarus has been pondering deceleration options too, and I’ll use some of our synergy with their work to consider what might be done.
The Bussard paper mentioned above is “Galactic Matter and Interstellar Spaceflight,” Astronautica Acta 6 (1960), pp. 179-194. Andrews and Zubrin’s key paper on the Bussard ramjet and drag is “Magnetic Sails and Interstellar Travel,” International Astronautical Federation Paper IAF-88-5533 (Bangalore, India, October 1988). Or you can read Zubrin’s well written exposition of all this in Entering Space: Creating a Spacefaring Civilization (New York: Tarcher/Putnam, 1999). This one should be on your shelf in any case.
by Paul Gilster | Mar 15, 2012 | Deep Sky Astronomy & Telescopes |
As promised, we now have the infrared sky at a new level of detail thanks to the labors of the Wide-Field Infrared Survey Explorer (WISE) mission, which has now mapped (with a few slight glitches) more than half a billion objects, from galaxies to stars to asteroids and comets. We can now expect a new wave of papers from the more than 2.7 million images WISE has delivered at four infrared wavelengths and can explore the WISE atlas of some 18,000 images ourselves.
The Big Picture
But first, I want to step back and look at astronomical discovery in context, a thought spurred by Larry Klaes, who sent me a note originally posted on the HASTRO-L mailing list (by Rich Sanderson, of the Springfield Science Museum in Massachusetts). Every now and then I read something that wraps back into the past and yet implies future things, generating a sense of connection with what the enterprise is all about. Such is the case in this passage Sanderson quotes from an 1875 book by Richard Proctor that looks at 19th Century transits of Venus. Remember, these are rare phenomena, occurring in pairs spaced eight years apart which are then separated by gaps of 121.5 years and 105.5 years. Listen to Proctor:
We cannot doubt that when the transits of 2004 and 2012 are approaching, astronomers will look back with interest on the operations conducted during the present “transit season;” and although in those times in all probability the determination of the sun’s distance by other methods…. will far surpass in accuracy those now obtained by such methods, yet we may reasonably believe that great weight will even then be attached to the determinations obtained during the approaching transits. I think the astronomers of the first years of the twenty-first century, looking back over the long transitless period which will then have passed, will understand the anxiety of astronomers in our own time to utilise to the full whatever opportunities the coming transits may afford; and I venture to hope that should there then be found, among old volumes in their book-stalls, the essays and charts by which I have endeavored to aid in securing that end (perhaps even this little book in which I record the history of the matter), they will not be disposed to judge over-harshly what some in our own day may have regarded as an excess of zeal.
Thus the past regards us, and in his own comment, Sanderson goes on to speculate about what’s ahead:
As Proctor had hoped, a copy of his little book did appear on a “book-stall” I visited in Ithaca, New York, from which it made the journey to Massachusetts to take up residence in my library. I wonder whose fingers will be caressing its pages in 2117.
For we do have a transit coming up on June 6, but after that, it will be December of 2117 before the next, and we can only wonder not only how astronomers of that day will observe it, but also about the techniques they will then be using to study planets around other stars. We can also wonder at the kind of nearby objects we will be considering as fair game for future space probes, given the results of missions like WISE. We’re learning that ‘rogue’ planets may be out there in huge numbers, and that brown dwarfs are interesting targets in their own right. Perhaps in the new WISE data we’ll find a few objects like these to put on our exploratory wish list, even as we imagine future astronomers looking back and marveling at our primitive equipment.
Analysis and Papers Ahead
But as we begin to dig into what WISE has produced, we’ve already learned that the mission has now identified, according to NEOWISE principal investigator Amy Mainzer, some 93 percent of the near-Earth asteroids larger than 1 kilometer, thus satisfying the congressional mandate for the SpaceGuard project.
NEOWISE is the asteroid-hunting portion of the WISE mission. Its efforts have also found fewer mid-size objects among near-Earth asteroids than used to be thought were there. The recent discovery of 2010 TK7, the first known Earth Trojan asteroid, underscores the capabilities of NEOWISE. Trojans are asteroids that share an orbit with a planet, circling the Sun in front of or behind the planet — they circle around the stable gravity wells called Lagrange points. 2010 TK7’s orbit is well known over the next 10,000 years, showing that at no time during that period will it approach any closer than 20 million kilometers to the Earth.
WISE is, of course, equally attuned to the study of distant objects, as in the image below, which shows the ‘light echo’ of the supernova event associated with Cassiopeia A, one of the most powerful radio sources in the sky. The light from the explosion reached the Earth around 1667 AD but seems to have gone unnoticed, probably because dust between the event and the Earth would have dimmed the explosion so as to make it all but invisible to the naked eye.
Image: The light echo of the explosion that produced Cassiopeia A. The central bright cloud of dust is the blast wave moving through interstellar space heating up dust as it goes. The blast wave travels fast – at an average speed of about 18,000 kilometers per second (11,000 miles per second) – but that is still only about 6% of the speed of light. The blast has expanded out to about a distance of 21 light-years from the original explosion. The flash of light from the explosion traveled faster – at the speed of light – covering over 300 light-years at the time that WISE took this picture. The orange-colored echoes further out from the central remnant are from dust heated as the supernova flash reached the dust centuries after the original explosion. Credit: NASA/JPL-Caltech/WISE Team.
Among the many discoveries of WISE are the Y-class brown dwarfs that are the coolest known class of stars. We now wait as the astronomical community sifts through the 15 trillion bytes of returned data in search of brown dwarfs and other interesting IR signatures in nearby space. The WISE all-sky archive with catalog and image data is available online along with instructions.
by Paul Gilster | Mar 14, 2012 | Antimatter |
Normally when we talk about interstellar sail concepts, we’re looking at some kind of microwave or laser beaming technologies of the kind Robert Forward wrote about, in which the sail is driven by a beam produced by an installation in the Solar System. Greg and Jim Benford have carried out sail experiments in the laboratory showing that microwave beaming could indeed drive such a sail. But Steven Howe’s concept, developed in reports for NASA’s Institute for Advanced Concepts, involved antimatter released from within the spacecraft. The latter would encounter a sail enriched with uranium-235 to reach velocities of well over 100 kilometers per second.
That’s fast enough to make missions to the nearby interstellar medium feasible, and it points the way to longer journeys once the technology has proven itself. But everything depends upon storing antihydrogen, which is an antimatter atom — an antiproton orbited by a positron. Howe thinks the antihydrogen could be stored in the form of frozen pellets, these to be kept in micro-traps built on integrated circuit chips that would contain the antihydrogen in wells spaced at periodic intervals, allowing pellets to be discharged to the sail on demand. The storage method alone makes for fascinating reading, and you can find it among the NIAC reports online.
Of course, we have to create the antihydrogen first, a feat achieved back in 2002 at CERN through the mixing of cold clouds of positrons and antiprotons. And it goes without saying that before we get to the propulsion aspect of antihydrogen, we have to go to work on the differences between hydrogen and antihydrogen, while investigating the various kinds of long-term storage options that might be used for antimatter. Does antihydrogen have the same basic properties as hydrogen? CERN is moving on to study the matter, with new work showing the amount of energy needed to change the spin of antihydrogen’s positrons.
The report comes from CERN’s Antihydrogen Laser Physics Apparatus (ALPHA) experiment, the same team that trapped antihydrogen for over 1000 seconds last year. Successful trapping now allows the analysis of the antihydrogen itself, applying microwave pulses to affect the magnetic moment of the anti-atoms. This BBC story quotes ALPHA scientist Jeffrey Hangst:
“When that happens, it goes from being trapped like a marble in a bowl to being repelled, like a marble on top of a hill,” Dr Hangst explained.
“It wants to ‘roll away’, and when it does that, it encounters some matter and annihilates, and we detect the fact that it disappears.”
Image: The ALPHA experiment facility at CERN. Credit: Jeffrey Hangst/CERN.
The work is part of a much larger program that will probe antihydrogen with laser light, the goal being to explore the energy levels within antihydrogen. What the work may eventually uncover, perhaps in addition to tuning up our methods of antihydrogen storage along the way, is whether there are clues in the makeup of antihydrogen that explain why the universe is filled with matter and not its opposite, given that both matter and antimatter existed in equal amounts in the earliest moments of the universe. The light emitted as an excited electron returns to its resting orbit is well studied in hydrogen and assumed to be identical in its antihydrogen counterpart.
These are early results that promise much, but the important thing is that the ALPHA team has demonstrated that their apparatus has the capability of making these measurements on antihydrogen. Uncovering the antihydrogen spectrum will take further work but could prove immensely useful in our understanding of the simplest anti-atom. We’re a long way from the antimatter sail concept, but Howe’s Phase II report at NIAC covered his own experiments with antiprotons and uranium-laden foils, critical work for fleshing out the architecture for a mission that may one day fly once we’ve mastered antihydrogen storage and learned to produce the needed milligrams of antimatter (current global production is measured in nanograms per year).
Antimatter’s promise has always been bright, given that 10 milligrams of the stuff used in an antiproton engine (not Howe’s sail) heating hydrogen through antimatter annihilation would produce the equivalent of 120 tons of hydrogen/liquid oxygen chemical fuel. But as soon as you start talking about the energy involved, the difficulty in producing and storing antimatter puts a damper on the entire conversation. That’s one reason why, at a time when antimatter costs in the neighborhood of $100 trillion per gram, finding natural antimatter sources in space is such an interesting possibility. It was just last year that we learned about the inner Van Allen belts’ roll in trapping natural antimatter, and James Bickford (Draper Laboratory, Cambridge MA) has been examining more abundant sources farther out in the Solar System.
The CERN work is reported in Amole et al., “Resonant quantum transitions in trapped antihydrogen atoms,” published online in Nature 9 January 2012 (abstract). For more on antimatter sources in nearby space, see Adriani et al., “The discovery of geomagnetically trapped cosmic ray antiprotons,” Astrophysical Journal Letters Vol. 37, No. 2, L29 (abstract / preprint). I discuss the recent results from the Pamela satellite (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) and provide sources for Bickford’s continuing work on naturally occurring antimatter in Antimatter Source Near the Earth.
by Paul Gilster | Mar 13, 2012 | Astrobiology and SETI, Exoplanetary Science |
I’ve held off a bit on the latest Kepler data release because I wanted some time to ponder what we’re looking at. The list of candidate planets here is based on data from the first sixteen months of the mission, and at first blush it seems encouraging in terms of our search for Earth-class planets. But dig deeper and you realize how much we still have to learn. Not all the trends point to the near ubiquity of rocky worlds in the habitable zone that some have hoped for. You might remember, for example, Carl Sagan famously saying (on ‘Cosmos’) that one out of every four stars may have planets, with two in each such system likely to be in the habitable zone.
Kepler’s Candidates and Some Qualifications
I remember being suitably agog at that statement, but we’ve learned more since. John Rehling, writing an essay for SpaceDaily, didn’t miss the Sagan quote and uses it to contrast with his own analysis of the new Kepler material showing that Earth-like planets may be considerably harder to find. Let’s talk about what’s going on here. A Kepler news release from February 28 breaks down the highlights. We find that the total count of Kepler planet candidates has reached 2321, with 1091 emerging in the new data analysis. Here we are dealing with 1790 host stars, and what caught everyone’s attention was this:
A clear trend toward smaller planets at longer orbital periods is evident with each new catalog release. This suggests that Earth-size planets in the habitable zone are forthcoming if, indeed, such planets are abundant.
Indeed, the Kepler catalog now holds over 200 Earth-size planet candidates and over 900 that are smaller than twice the Earth’s size, which makes for a 197 percent increase in this type of planet candidate (with planets larger than 2 Earth radii increasing at about 52 percent). 10 planets in the habitable zone (out of a total of 46 planet candidates there) are near Earth in size. We also learn that the fraction of host stars with multiple candidates has grown from 17 to 20 percent, and that improvements in the Kepler data analysis software are helping us identify smaller and longer period candidates at a faster than expected clip. So far, so good.
What John Rehling did was to go to work on two biases that affect the Kepler data set: 1) The Kepler data is more complete in regions close to the host star, which is reflected in the fact that over 90 percent of the observed candidates have shorter periods than Mercury; and 2) Because of the transit methodology used, larger planets are more readily observed than small ones. And here we note (see diagram) that most observed candidates are considerably larger than Earth.
Rehling uses the two forms of bias to calculate a numerical de-bias factor, having put the observed candidates into bins based on radius and orbital period. From his essay:
Where the positive observations are significant in number, we can calculate the universal abundance of such planets. Where there have been few or no observations, we can use the de-bias factor to infer probabilistically a ceiling on the number of such worlds.
A similar approach by Wesley Traub used the data from the earlier four-month data release to calculate absolute frequencies and furthermore to extrapolate trends in planet radius and orbital period to project that about 34% of stars host an earth-sized planet in the habitable zone, a happy speculation for the future goal of finding truly earthlike planets as possible abodes for life.
A happy speculation indeed, but as adjusted for the new data release (Traub was working with bins with nothing longer than 50-day orbital periods), we can begin to tune up the accuracy. Even so, we should note that 16 months of observation isn’t enough to flag an Earth-like planet (remember, we need three transits, so to detect a true Earth analogue, we need 24 months of observation or more). We’re extrapolating, then, based on trends, and Rehling finds two trends at work in the new data, the first being that we see more Earth-size planets that are close to their stars, the second being that we see more giant planets located farther away from their stars.
The upshot: These trends are not favorable, because only the larger planets continue to increase in frequency as we move into the longer dataset, while the ‘super-Earth’ and Neptune-class candidates peak in frequency “at orbital periods roughly corresponding to the upper end of the four-month release’s window.” From the essay (italics mine):
Overall, we see that our solar system is qualitatively typical in placing larger planets farther out than smaller planets. However, it is quantitatively atypical: While Kepler shows us the happy result that there are almost certainly several planets for every star, it shows us that our solar system is distributed freakishly outwards, in comparison to more typical planetary systems.
In Rehling’s estimate (and you should read the entire essay, where he backs up his analysis with useful graphics), the frequency of Earth-like worlds is not Traub’s robust 34 percent but something closer to 0.7 percent. We can raise that a bit by extending the parameters (including bins surrounding Earth’s bin) and by including somewhat smaller planets, and what we then emerge with may get as high as 9 percent. And at the lower end, if Earth analogues are less abundant than 3 percent, then it’s possible we may find not a single one with Kepler.
What to make of this? The most obvious point is that the Kepler mission is ongoing, and that we need to see what the next data release brings. We’re still extrapolating as we gradually move the zone of detection outwards, gradually filling up the relevant bins. The second point is that given the vast number of stars in the galaxy, even with the much lower assessments of Rehling’s analysis, we may still be looking at hundreds of millions of habitable terrestrial planets.
Ramifications of ‘Rarer Earths’
But Rehling’s case is highly interesting in two directions. First, the kind of spectroscopic follow-ups we need to make on planet candidates are rendered more difficult by the distance of the Kepler stars from us. As we look toward future missions to characterize the atmospheres of terrestrial worlds, we’re going to need planets that are relatively close, but rarer ‘Earths’ means that such planets are farther apart than we’d like them to be. That has obvious implications as well for our favorite Centauri Dreams subject, future probes sent to nearby solar systems.
So perhaps we have to stay creative when it comes to habitable zones and astrobiology. We already know that M-class stars are the most common in the Milky Way by a huge margin (as many as 80 percent of all stars may fit this class). Here we’re not talking about an Earth analogue, but planets at the right distance from M-dwarfs may be habitable despite the problems of tidal lock and solar radiation. Then too, we can consider that if most solar systems really are compressed toward the star, there may be many gas giants in the habitable zone of stars like our Sun and into the K-class. Here we have the possibility of habitable conditions on moons.
G-class stars like our Sun are not themselves all that common — I believe that about 3.5 percent of all stars fit the bill. But K-class stars like Centauri B are also in the picture (8 percent) along with the above-mentioned red dwarfs, and we are steadily finding out more about the variety of planetary system configurations around such stars. Rehling notes, too, that as more Kepler data become available, the frequency of planets as a function of orbital period may show a second peak. No one is saying that we are finished with Kepler, not by a long shot. What we are trying to do is to draw the maximum amount of information out of what we do have. What will the terrestrial planet outlook be after Kepler’s next release?
by Paul Gilster | Mar 12, 2012 | Culture and Society |
It’s shaping up to be an interesting week. I want to get to the recent Kepler data release, and also to the antimatter news from CERN, and I also want to talk about everything from decelerating an interstellar craft to models of expansion into the galaxy a la Frank Tipler. [And thanks to Centauri Dreams reader Eric Goldstein for reminding me of the upcoming WISE data release on the 14th!]. For today, though, let’s look at two upcoming conferences, especially since I’m running behind in getting to the first of them, the CONTACT 2012 gathering, which is coming up right away.
The full title of this one is CONTACT: Cultures of the Imagination, and it’s a meeting with a rich history. Back in 1979, Jim Funaro was teaching a course in anthropology at Cabrillo College (Aptos, CA) that used science fiction as a vector into the scientific issues his course raised. The course allowed students to go to work creating cultures and, in a game-like simulation, to explore how the fictional societies interacted with each other. By 1983, Funaro was able to use this ‘laboratory experiment’ in anthropology as the main event of the first CONTACT meeting, set up to be a national academic conference bringing scientists, artists and writers together.
Interdisciplinary Insights into ETI
When Funaro founded CONTACT, his goal was to encourage interdisciplinary thinking, which must have been much in the air back in 1983, considering that this was also the year of the storied Interstellar Migration and the Human Experience conference held at Los Alamos. The latter ranged from astrophysics to sociology, psychology and history and probed how emerging technologies would affect future human expansion into the cosmos. Meanwhile, CONTACT had been energized by Funaro’s interactions with science fiction writer Frank Herbert, whose classic novel Dune was one of the books used in his class as an example of a credible created culture.
How Funaro lured other writers and scientists into CONTACT is told on the conference’s website. In any case, writers like Michael Bishop, Larry Niven, John Brunner and C.J. Cherryh soon became involved, and Funaro worked with artist Joel Hagen to launch the first world-building project. Although the first CONTACT conference ran in April of 1983 (in Santa Cruz), the culture-building simulations of what Funaro called the ‘Bateson Project’ (after anthropologist Gregory Bateson) were a success, and anthropology as simulation/performance art was established, while the original simulation idea was renamed “Cultures of the Imagination.”
Funaro calls CONTACT III “the first time it worked,” noting that this was the conference where lessons learned from the first two conferences were first implemented. The cross-disciplinary nature of the proceedings is easily seen in his account of building the pre-conference package:
Poul Anderson gave us a planet, Ophelia, with its primary and solar system… We then sent the planetary specifications to C. J. Cherryh, who suggested the Mossback [the resident alien of the planet] and provided us with its basic design. Next, Larry Niven elaborated on this alien, contributed other species for the ecology and explained the conditions that the human team would face on this world. Finally, Joel Hagen produced some sketches of the critters. This “homework” was then distributed to all the guests several weeks before the conference.
Specialized teams at the conference then went to work to develop the world and its culture, and sequential workshops developed the key issues. Role-playing developed and became a major tool. Funaro acknowledges that such simulations are artificial and limited:
But, like the real intercultural contacts that anthropologists have been participating in for more than a century here on our home planet, the interaction was unrehearsed, proceeded carefully from known behavioral and ethnographic methodologies towards consistent and ethical choices of action, and provided at least a possible model for developing a protocol for an extraterrestrial encounter. And the value of spontaneous role-playing in enhancing the effectiveness of the simulation was convincingly (however unexpectedly) demonstrated. It has been an essential part of COTI forever after.
Frank Drake will be the keynote speaker at CONTACT 2012 at the Domain Hotel in Sunnyvale (CA), with conference sessions running from March 30 to April 1. You can see the full schedule along with abstracts of the talks here. Among the offerings I note in particular Kathryn Denning on our expectations in interstellar contact (“Unboxing Pandora”), Albert Harrison on Russian cosmism, a philosophical movement that emerged around 1900 and influenced our modern views of space exploration, and Seth Shostak’s sure to be controversial “Broadcasting into Space: Recipe for Catastrophe?” If that last one doesn’t raise the temperature in the room, nothing will.
Searching for Life Signatures
The call for papers for the Fourth IAA Symposium on Searching for Life Signatures is available online. The conference, to be held at the Kursaal Congress Centre in San Marino (Italy) runs from September 25-28 of this year, ranging over traditional SETI and so-called Active SETI (Messaging to ETI), along with studies of biosignatures and exoplanet discovery. For those intending to be at the 63rd International Astronautical Congress (IAC), note that Searching for Life Signatures will take place in the week just prior to the IAC, which runs from October 1-5.
Image: Northern Cross radio telescope at Medicina (Bologna, Italy), 564 by 640 m, 30000 square meter multi-element, centered at 408 MHz. Credit: Simona Righini/INAF.
The SETI Permanent Committee of the International Academy of Astronautics (IAA) invites abstracts to be submitted to the Symposium. The deadline for abstract submission is Sunday June 24. Information about travel possibilities is available at the site — I notice that Rimini and San Marino airport is closest to the venue (about 25 kilometers), but Bologna is the more likely option for those coming in from overseas (132 kilometers from San Marino), while Milan is a good 300 kilometers out, though with hourly train connections to Rimini and thence by bus to San Marino.
I’ll have more details about the San Marino conference as abstracts become available.
