We know about an extremely interesting planet around Proxima Centauri, and there are even plans afoot (Breakthrough Starshot) to get probes into the Alpha Centauri system later in this century. But last April, when Breakthrough Initiatives held a conference at Stanford to talk about this and numerous other matters, the question of what we could see came up. For in Alpha Centauri, we’re dealing with three stars that are closer to us than any other. If there are planets around Centauri A and/or Centauri B, are there ways we could image them?
This gets interesting in the context of Project Blue, a consortium of space organizations looking into exoplanetary imaging technologies. This morning Project Blue drew on the work of some of those present at Stanford, launching a campaign to fund a telescope that could obtain the first image of an Earth-like planet outside our Solar System, perhaps by as early as the end of the decade. The idea here is to ignite a Kickstarter effort aimed at raising $1 million to support needed telescope design studies. A $4 million ‘stretch goal’ would allow testing of the coronagraph, completion of telescope design and the beginning of manufacturing.
Project Blue thinks it can bring this mission home — i.e., launch the telescope and carry out its mission — at a final cost of $50 million (the original ACEsat was a $175 million design). The figure is modest enough when you consider that Kepler, which has transformed our view of exoplanets, cost $600 million, while the James Webb Space Telescope weighs in at $8 billion. About a quarter of the total cost, according to the project, goes into getting the telescope into orbit, which will involve partnering with various providers to lower costs.
But Project Blue also hopes to build a public community around the mission to support design and research activities. Jon Morse is mission executive for the project:
“We’re at an incredible moment in history, where for the first time, we have the technology to actually find another Earth,” said Morse. “Just as exciting — thanks to the power of crowdfunding — we can open this mission to everyone. With the Project Blue consortium, we are bringing together the technical experts who can build and launch this telescope. Now we want to bring along everyone else as well. This is a new kind of space initiative — to achieve cutting-edge science for low cost in just a few years, and it empowers us all to participate in this moment of human discovery.”
I go back to last April because it was at Stanford that I saw Eduardo Bendek’s model of a small space telescope called ACEsat, which was conceived at NASA Ames by Ruslan Belikov and Eduardo Bendek and submitted (unsuccessfully) for NASA Small Explorer funding. Belikov had gone on to present the work at the American Astronomical Society meeting in 2015 (see “How to Directly Image a Habitable Planet Around Alpha Centauri with a ~30-45cm Space Telescope,” available here). You’ll recall that Ashley Baldwin wrote up the concept in superb detail on this site in December of that year as ACEsat: Alpha Centauri and Direct Imaging.
Now we have Project Blue, which has connections to the BoldlyGo Institute, its offshoot Mission Centaur, the SETI Institute and the University of Massachusetts Lowell. The aim is to launch a space telescope with a 45-50 centimeter aperture, looking for potentially habitable planets from 0.5 to 1.5 AU within the habitable zones of both Centauri A and B. The ultimate hope, then, is to ‘see blue’ — meaning oceans and atmosphere, a world on which life could emerge. This is Sagan’s ‘pale blue dot,’ only now it’s not our own planet but an Earth 2.0.
The Project Blue space telescope would spend two years in low Earth orbit accumulating image after image — hundreds, thousands, tens of thousands — as a way of teasing out its faint targets. When it comes to ‘another Earth,’ Centauri A and B up the ante on Proxima Centauri. The Proxima planet may well be habitable, but a true Earth analog is not going to be tidally locked to its star, as Proxima b probably is, and it’s not going to orbit a red dwarf.
Neither Belikov or deputy principal investigator Eduardo Bendek are formally connected to Project Blue, but their work in the form of papers and conference presentations feeds directly into the concept driving the project. The original mission now cedes the floor to the private sector, whose job it will be to raise enough cash to support the development of the needed coronagraph to filter out the light of two very close stars, along with other key flight hardware elements. The next step, though, long before building flight hardware, is to finalize the telescope design.
The new Kickstarter campaign will pay for analysis, design, and simulations, but Project Blue has an eye on other partnerships as well as wealthy donors and foundations. Usefully, the project should be able to test coronagraph technologies similar to those being considered on much larger space instruments currently under study by the major space agencies, thus providing a useful testbed for such designs. To make this work, everything must fall into place — the coronagraph for starlight suppression, a deformable mirror to feed the coronagraph and rock-solid stability. No aspect can be allowed to fail if the mission is to achieve its goal.
If the Project Blue planners are correct, we can solve the attendant problems and get this mission into space is as little as 4 to 6 years. The goal is hugely ambitious but it also opens the door to citizen-science, with private donors contributing to an instrument that will not be the result of a government program or a for-profit commercial space effort. The initial Kickstarter campaign is designed to bolster the technical groundwork needed for the telescope, but stretch goals could see publicly funded flight component manufacturing.
Looking for Earth-like planets around other stars is like looking for bioluminescent algae next to a lighthouse. But I keep coming back to that Breakthrough Discuss meeting in Stanford, because I remember Ruslan Belikov telling his audience that the key advantage of Alpha Centauri is how large the habitable zones around its component stars appear in terms of angular size. We would need a significantly larger instrument to attempt something similar around other nearby stars. The Alpha Centauri stars are nature’s gift, and it’s one we would do well to exploit. Check the Kickstarter page for more on this low cost, high impact idea.
For more on the technical background of the ACEsat concept, see Belikov et al., “How to Directly Image a Habitable Planet Around Alpha Centauri with a ~30-45cm Space Telescope” (preprint) and Bendek et al., “Space telescope design to directly image the habitable zone of Alpha Centauri” (preprint).
It was inevitable that KIC 8462852 would spawn a nickname, given the public attention given to this mystifying star, whose unusual lightcurves continue to challenge us. ‘Tabby’s Star’ is the moniker I’ve seen most frequently, but we now seem to be settling in on ‘Boyajian’s Star.’ It was Tabetha Boyajian (Louisiana State) whose work with the Planet Hunters citizen science project brought the story to light, and in keeping with astronomical naming conventions (Kapteyn’s Star, Barnard’s Star, etc.), I think the use of the surname is appropriate.
Planet Hunters works with Kepler data, looking for any dimming of the 150,000 monitored stars that may have gone undetected by the automated routines that hunt for repeating patterns. Boyajian’s Star cried out for analysis, dimming in odd ways that flagged not the kind of planetary transit across the face of a stellar disk that researchers expected but something else, something that would make the star dim by as much as 22 percent, and at irregular intervals. That led to a variety of hypotheses, the best known of which is a large group of comets, but we also have evidence that the star has been dimming at a steady rate.
Image: Tabetha Boyajian, looking up, presumably at Boyajian’s Star (caption swiped from Jason Wright’s page at Penn State).
With the story this unsettled, this morning’s energizing news is that Boyajian’s Star is now being examined by Breakthrough Listen. Working with Jason Wright, now a visiting astronomer at UC Berkeley, as well as Boyajian herself, the SETI project intends to devote hours of listening time on the Green Bank radio telescope in West Virginia to the star. You’ll recall that Breakthrough Listen is the $100 million SETI effort funded by the Breakthrough Prize Foundation and its founder, investor Yuri Milner. The Breakthrough Starshot project described often in these pages is also a Breakthrough Prize Foundation initiative.
As Andrew Siemion (director of the Berkeley SETI Research Center and co-director of Breakthrough Listen) explains in the video above, the project has access to the most powerful SETI equipment available, meaning its scientists can study Boyajian’s Star at the highest levels of sensitivity across a wide range of possible signal types. But the Green Bank effort will hardly be the first, for Boyajian’s Star has already excited a great deal of interest, as Siemion explains:
“Everyone, every SETI program telescope, I mean every astronomer that has any kind of telescope in any wavelength that can see Tabby’s star has looked at it. It’s been looked at with Hubble, it’s been looked at with Keck, it’s been looked at in the infrared and radio and high energy, and every possible thing you can imagine, including a whole range of SETI experiments. Nothing has been found.”
In Green Bank, Breakthrough Listen has access to the largest fully steerable radio telescope on the planet. Observations are scheduled for eight hours per night for three nights in the next two months, the first having taken place on October 26. The plan is to gather as much as 1 petabyte of data over hundreds of millions of individual radio channels. Siemion describes a new SETI instrument that can examine “…many gigahertz of bandwidth simultaneously and many, many billions of different radio channels all at the same time so we can explore the radio spectrum very, very quickly.”
Breakthrough Listen will be observing using four different radio receivers on the Green Bank instrument in a frequency range from 1 to 12 GHz, a range beginning, Siemion says, at about where cell phones operate up through the frequencies used for satellite TV signals.
Image: The Green Bank Radio Telescope (GBT) focuses 2.3 acres of radio light. It is 148 meters tall, nearly as tall as the nearby mountains and much taller than pine trees in the national forest. The telescope is in a valley of the Allegheny mountains to shield the observations from radio interference. Credit: NRAO/AUI.
Yesterday’s live video chat from Green Bank with Tabetha Boyajian, Jason Wright and Andrew Siemion is now available online, with the trio answering questions about the ongoing study. Boyajian was asked as the session opened how many comets it would take to reproduce the effects being observed around KIC 8462852. The answer: Hundreds to thousands of “very giant comets” just to reproduce the last 30 days of the data.
The numbers give no particular credence to the idea that we may be looking at some kind of artificial construction project around Boyajian’s Star, but they do underline how mysterious are the processes, assuming they are natural, that are driving this phenomenon. Boyajian called the comet hypothesis ‘pretty outrageous,’ but went on to say that of all the explanations, it is the one she most favors, as all other explanations are likewise outrageous.
On that score, I want to mention Jason Wright’s paper, written with Steinn Sigurðsson at Penn State, looking at other possible solutions to the Boyajian’s Star puzzle. It’s particularly useful early on in a section devoted to the follow-up work that has occurred, including the SETI studies with the VERITAS gamma-ray observatory, the Allen Telescope Array and the Boquete Optical SETI Observatory, but also reprising the interesting controversy over the dimming of the star. If you need to catch up with Boyajian’s Star, this is the place.
Wright and Sigurðsson conclude that long-term dimming would not fit well with the comet hypothesis, leaving us still searching for an answer. What does work its way up the chain of plausibility? An unusually dense region of the interstellar medium or a chance alignment with a localized molecular cloud occurring between us and the star is in the mix. The latter might be a so-called ‘Bok globule,’ an isolated and dark nebula dense with dust and gas.
The comet hypothesis is still in play, but a number of other explanations are problematic:
Less compelling, but difficult to rule out, are intrinsic variations due to spots, a “return to normal” from a temporary brightening (due to, perhaps, a stellar merger) and a cloud of material in the outer solar system. We find instrumental effects, other intrinsic variation in Boyajian’s Star, and obscuration by a disk around an orbital companion to Boyajian’s Star very unlikely to be responsible.
Read the paper for the entire list, which includes, with plausibility listed as unclear, the idea of artificial structures (“Would find support if all natural hypotheses are ruled out, we detect signals, or if star suffers significant achromatic extinction.”) The paper is Wright and Sigurðsson, “Families of Plausible Solutions to the Puzzle of Boyajian’s Star,” accepted at the Astrophysical Journal (preprint). But see also Jason Wright’s 10-part popular summary on Boyajian’s Star, which goes through all the options.
As we move into the outer Solar System and beyond, the possibility exists that we may encounter an extraterrestrial species engaged in similar exploration. How we approach first contact has been a theme of science fiction for many years (Murray Leinster’s 1945 story ‘First Contact’ is a classic treatment). In the essay below, Ken Wisian looks at how we can develop contact protocols to handle such a situation. A Major General in the US Air Force (now retired) with combat experience in Iraq, Afghanistan and the Balkans, Ken brings a perspective seasoned by command and a deep knowledge of military history to issues of confrontation and outcomes, building on our current rules of engagement to ask how we will manage an encounter with another civilization, one whose consequences would be momentous for our species.
By Ken Wisian Ph.D
Galactic Ventures LLC, Austin, Texas
Abstract
How do two ships approach each other in a first contact setting? When it happens it will be a pivotal moment for human history. The slightest mistake or misperceived intention could cascade into violence. Therefore even future deep space robotic probes, let alone a true interstellar ship whether crewed by humans or AI, should incorporate courses of action for this possibility,
The development of first contact protocols is obviously rife with unknowns since we only have a one-planet historical data set build on; nevertheless we must proceed. The bulk of the thinking on first contact so far has focused on a remote contact via electromagnetic signal exchange (SETI) or finding non-sentient microbiota (aka Apollo post-mission quarantine), but what if we stumble upon another intelligence in space? Admittedly, this may not be the most likely course of action, but as we start to move deeper into space it is an increasing possibility. Through centuries of trial and error, protocols have been developed for military ship and aircraft encounters on Earth. These earth protocols provide as good a basis as we have for building extraterrestrial first contact protocols.
This paper will review human rules of encounter currently used and build a set of simple rules for a ship-to-ship encounter in space based on the assumption that there is no effective communication prior to or during the encounter.
1. Introduction
How do you approach a totally unknown entity in such a way as to not provoke a hostile reaction? This is not as easy a question as it might first appear. We are loaded with human-cultural preconceptions that are frequently subconscious. An example; smiling in humans is universally regarded as a friendly gesture, but in some primates and most species on earth (with a face that is) showing your teeth is a dominance/aggressive/threat gesture. And this difference here on earth exists between closely related species – who is to say how divergent the interpretation of gestures might be between species that evolved in different star systems? Another example is the white flag. Most industrialized states recognize it as a sign of surrender, some also would recognize its use to request parley, but it is far from universal in time or across cultures even today on earth. Thus nothing can be taken for granted and substantial on-the-spot sound judgement will be required.
Why worry about the vanishingly small chance of an unanticipated first contact? Risk management both in the military and civilian world considers not just the probability of an event, it also considers the potential consequences. In the case of a first contact, the odds of such an event are nearly vanishingly small, but they are cancelled out (and then some) by the off-the-chart potential impact of an encounter unintentionally entering an instantaneous, violent escalation spiral. Thus it is critically important that humans think through first contact in space before it happens.
Science fiction (SF) deals frequently with first contact scenarios. The volume of material is immense – far too much to even briefly review here. SF has explored, often quite well and with great “outside the box” thinking probably every conceivable scenario. So while there are no specific SF references here, the body of SF work informs all aspects of this paper.
We have a limited knowledge base from which to start and extrapolate general rules for first encounters, namely one technological species – homo-sapiens. This situation presents a danger that we must guard against as best we can; anthropomorphic bias. Given that potential bias, we will none the less start by looking at what humans do in the closest analog we currently have for first encounters; the meeting of unknown, neutral or potentially hostile ships and or aircraft. Through trial and (often fatal) error there are now well-defined rules of conduct for these situations (up to the level of international law).
The human-human contact experience is perhaps our best foundation upon which to build a set principles and protocols for a potential encounter in space. The envisioned scenario; two ships meeting in space rest on several assumptions.
Assumptions:
1. No effective telecommunication. There may be attempts to communicate via electromagnetic or other means, but understanding has not been achieved, thus we are without effective communication – “comm-out”.
2. Neither side is overtly hostile, but both are guardedly cautious.
3. At least one of the ships involved has “reasonable” maneuvering capability.
a. This will most likely be an “endpoint” encounter, in a solar system. An encounter in transit in deep interstellar space would likely mean neither ship has the ability to stop and/or maneuver in order to match vectors and effect a rendezvous.
Not a scenario assumption, but an important point is that these protocols apply just as well to Artificial Intelligence (AI) crewed ships as they do to human crewed ships. Also, ships is taken to include space stations or other similar outposts. Even probes without true AI can incorporate complex, branched Courses Of Action (COAs) for dealing with encounters. For instance, detection of radiation anywhere in a wide range of EM frequencies that does not correlate with known astronomical sources would be a target to slew all sensors to and report on. At that point, depending on level of sophistication, you enter COAs for determining artificiality etc.
Image: Confronting the unknown. A still from Steven Spielberg’s Close Encounters of the Third Kind. Credit: EMI Films / Columbia Pictures.
2. Current human protocols
There are internationally accepted protocols for encounters between ships and correspondingly between aircraft. Some are based on international law and custom (Law of the Seas), some are rules by governing bodies (International Civil Aviation Organization). Similar laws and rules exist also within the boundaries of individual countries. Regardless of origin, they follow broadly similar, mostly common sense (at least to us nowadays) paths based on centuries of experience. Underlying much of this is an unwritten intent to minimize potential misunderstanding that could lead to violence. This point is critical for our purposes. It is difficult enough to minimize misunderstanding and escalation within our own species, it could be significantly more difficult to do the same when civilizations from different stars meet.
Much of the law and customs for ships at sea pertain to piracy or the right of a country to inspect a ship to ensure that it is conducting legal business (particularly in territorial waters). Even here though reasonable cause is required for more than a cursory inspection. The rules governing intercept of aircraft are more slanted towards the need to immediately protect a country from devastating attack that can result from a craft moving at or above supersonic speed and thus can lead much more quickly to lethal action.
In all air and sea cases there is a hierarchy of communication means used to establish meaningful dialog between ships from straightforward radio communication to flag and light signals up to and including weapons fire – the shot across the bow, so yes, even gunfire can be a form of communication. With aircraft there are no flags, but brief maneuvers (such as rocking wings) can be used for communication.
For ships at sea, there are rules for avoiding collision such as pass to the right (starboard). There is also a rule that the most maneuverable ship has primary responsibility to avoid collision. For example a functional ship at sea that comes upon a ship adrift, unable to maneuver, besides having a responsibility to help, is responsible to maneuver so to avoid collision. Correspondingly, the less maneuverable ship is obligated to maintain constant speed and heading or come to a stop. For aircraft meeting aircraft there is a similar most maneuverable has primary responsibility to avoid collision rule, so for instance a powered aircraft has responsibility to avoid a hot air balloon.
For military aircraft or ships meeting other military ships or aircraft there are additional guidelines that are critical for avoiding escalation. First is to avoid collision courses or aggressive maneuvers such as those designed to put one in a (better) shooting position. Right along with that are restrictions on pointing guns or (and this gets tricky) putting support systems such as radars into modes such as target track that are standard preparatories to firing weapons. Radar modes have become particularly problematic as technology has advanced; many weapon system no longer require a distinctive target tracking mode in order to shoot. Furthermore electromagnetic jamming during an intercept is a potentially hostile act. These rules unfortunately are not universally followed and not following them has resulted in very serious international incidents to the present day.
3. Excursion into past human civilizational first contacts
The past record of human civilization first contacts is a well-trodden area of history and will only briefly be covered as it pertains to extraterrestrial scenarios – the longer term consequences such as disease transfer and cultural domination will not be addressed. Less commonly studied though are the details and consequences of the actual first contact. The bottom line is that first encounters have often, though not always turned violent and in such cases the side with a major technological advantage usually wins. Commonly Western Europeans with well advanced gunpowder technology encountering stone or bronze/iron age technologies have won most violent encounters, but have sometimes been overcome bu numbers. The question of why encounters have turned violent and the cause is much more ambiguous – some encounters have been peaceful, but in many cases territoriality and xenophobia have been prompt causes for violence. Who can say for sure that any species encountered may not have these traits (even more markedly than humans)? Perhaps more disturbing, there are human cultures that consider war/killing a necessary prerequisite to full citizen status. Fortunately none of these cultures are dominant on earth today, but what if such a culture achieved an interstellar civilization?
4. Towards a protocol
The above review of human encounter situations and history gives us a good starting point for thinking about alien ship to ship encounters. First a few general principles to go with the assumptions already laid down at the beginning. These principles are distilled from the human contact procedures above which in turn are built upon millennia of experience.
Contact principles
1. Be predictable
2. Avoid any appearance of hostile intent
3. Attempt communication
These seem straightforward, but #2 has many subtleties and #3 is a very complex subject which is beyond the scope or this paper or the expertise of the author.
The principles are in priority order; communicating is far less important than the closely related ideas of being predictable and not showing hostile intent. These principles are broadly applicable in human experience. For example besides applying at the level of international affairs, these are also appropriate at the level of individuals for an encounter with law enforcement around the world, driving a car, or encountering strangers on the street.
What has not been stated before is the underlying motivation for these principles and that is to avoid putting the other party into a position where they have to make a snap judgement about your intent. In human interactions between two wary parties ambiguity of intent is almost always interpreted in the most hostile way (unless the parties have a considerable experience base, which in a first contact they will not, that allows them to presume accidental ambiguity versus hostility). It is also important to note that for the foreseeable future, considering that we have only just become a spacefaring species, we are most likely to be the less technologically advanced of the two encountering civilizations and thus it becomes particularly important that we not precipitate any escalation that we are very likely to lose.
Image: David Bowman (Keir Dullea) and a famous monolith, from Stanley Kubrick’s 2001: A Space Odyssey. Credit: Metro-Goldwyn-Mayer.
First, be predictable. Being predictable is taken to mean with respect to maneuvering primarily. If it is possible to determine that one ship has a decided maneuver advantage on the other, then rendezvous can be attempted with the ships adopting the convention of the most maneuverable ship takes primary responsibility for a safe rendezvous. In these cases gradual, deliberately slow maneuvers would be employed even if there is capability to rapidly affect course changes. With regards to maneuvers there are multiple COAs available. The simplest is to make no changes to what you are doing; if “coasting” – continue, if drive engines are engaged, continue at current setting. Alternatively, you might want to stop engines (this is not the same as stopping in space, which is probably not a practical thing to do (for that matter what frame of reference would you use to determine “stop”)). Regardless unless there is an overriding need (discussed shortly), maintain heading (in three dimensional terms – maintain vector).
What if one ship is approaching an orbital situation – remember that an encounter will most likely be at the endpoint of an interstellar journey. In such a case, in order to avoid catastrophe it might be necessary to start or continue maneuvers to achieve a safe, stable orbit, but this brings with it a slightly elevated risk misunderstanding. In this situation we would be forced to rely on the other parties’ ability to perceive the obvious need to conduct maneuvers. Note the potential for unintended consequences; for a ship that would need to “flip” end-to-end in order to reverse its engines and thrust, you would not want to “sweep” your thrust vector across the other ship and therefore place them in a position of having to decide if you are about to use you most destructive weapon (main drive) on them.
Secondly, avoid any appearance of hostile intent. This is a much more problematic issue than being predictable. The main problem with avoiding appearance of hostile intent is the perception problem. In any encounter between entities that do not share a common culture, there can be serious misinterpretations of intent and meaning, as exemplified by the smile and white flag examples earlier.
If a ship is equipped with weapons you would obviously not want to point them at the other ship. If practical stowing or deactivating them is good, but this then poses another question: would you want to have weapons that require time to activate completely deactivated, thus costing valuable time to spin up if things go bad?
Besides weapons, other non-destructive systems are used by the military; jammers and expendable decoys for example. These would obviously not want to be triggered (but what might be the difference between jamming and a high-powered attempt at communication?).
“But we are peaceful and will not be going armed into space” you say. Any conceivable ship will have technology/systems that are dual-use. The main drive of any self-powered interstellar ship will obviously be extremely high energy and could be used as a weapon of great range and destructive power, thus even a peaceful braking maneuver (with the drive off) that sweeps the business end of the drive towards the other ship, could prompt a swift reaction. Other systems that must be accounted for include communication systems; radios or lasers strong enough to communicate across interstellar distances could be very destructive at short range. So what is one to think when you see a high power laser move to point at you? Perhaps part of a communication protocol would be to only use low-power omnidirectional radio until good understanding is established. Shielding to protect ship and crew from radiation and or collisions has obvious military application – do you reduce its power, turn it off, or leave it in normal on mode? Can you? What if there is an active collision prevention system that destroys or pushes objects out of the way – that has major weapon potential. Is it safe to turn it off?
Tertiary considerations. Avoid looking like you are hiding (aircraft that turn off transponders are usually considered to have hostile or at least illegal intent). Turn on lights and anything else that makes you easily visible (but will this in turn blind any of the other ships sensors?). In your turn you will obviously use every sensor available to learn about the other ship, but passive sensors are probably best until goodwill is firmly established – an active radar scan may look like targeting to another party (just as targeting and search modes of radars are often indistinguishable in modern aircraft). A decoy, a probe, or a vessel containing materials to allow for communication and understanding, might be indistinguishable from a bomb, when launched from a ship.
Lastly, at what range do these actions need to start? As early as practical, probably at detection of the other ship. Your need to be predictable starts when they can see you and that is probably at least at the point when you can see them, if not much earlier.
5. Conclusion
What can be determined from the above discussion is that there are vast unknowns in any potential extraterrestrial encounter in space where effective communication is not established in advance. In these circumstances there are good principles to follow – be predictable, display no hostile intent, and attempt to establish communication, but the specific actions involve many gray areas where judgement, assumptions, or just plain hope, will be the guide. For any ship making an interstellar journey the scenarios must be “gamed” extensively in advance, but any COAs or checklist for an encounter should only be a guide/starting point. Flexibility, sound judgement and quick learning will be very important in these circumstances. The number one goal is to not put the other party in the position of having to make an instantaneous judgement about your intent.
I don’t envy the track chairs at any conference, particularly conferences that are all about getting large numbers of scientists into the right place at the right time. Herding cats? But the track model makes inherent sense when you’re dealing with widely disparate disciplines. Earlier in the week I mentioned how widely the tracks at the 100 Year Starship Symposium in Houston ranged, and I think that track chairs within each discipline — already connected to many of the speakers — are the best way to move the discussion forward after each paper.
Still, what a job. My friend Eric Davis, shown at right, somehow stays relaxed each year as he handles the Propulsion & Energy track at this conference, though how he manages it escapes me, given problems like three already accepted presentations being withdrawn as the deadline approached, and one simple no-show at the conference itself. Unfortunately, there were no-shows in other tracks as well, though the wild weather the night before the first day’s meetings may have had something to do with it.
Processes will need to be put in place before future symposia to keep this kind of thing from happening. Fortunately, Eric is quick on his feet and managed to keep Propulsion & Energy on course, and I assume other track chairs had their own workarounds. A high point of the conference was the chance to have dinner and a good bottle of Argentinian Malbec with Eric and Jeff Lee (Baylor University), who joined my son Miles and myself in the hotel restaurant.
The Antimatter Conundrum
I found two papers on antimatter within Eric’s track particularly interesting given the challenge of producing antimatter in sufficient quantity to make it viable in a future propulsion system. We’d love to master antimatter because of the numbers. A fusion reaction uses maybe one percent of the total energy locked up inside matter. But if you can annihilate a kilogram of antimatter, you can produce ten billion times the energy of a kilogram of TNT. In nuclear energy terms, the antimatter yields a thousand times more energy than nuclear fission, and 100 times more energy than fusion, a compelling thought for interstellar mission needs.
Sumontro Lal Sinha described the requirements for a small, modular antimatter harvesting satellite that could be launched into the Van Allen radiation belt about 15,000 kilometers up. I was invariably reminded of James Bickford’s ideas on creating an antimatter trap in an equatorial orbit around the Earth that could harvest naturally occurring antiparticles — Bickford has always maintained that space harvesting of antimatter using his ‘magnetic scoop’ is five orders of magnitude more cost effective than producing antimatter on Earth. In any case, antimatter resources here and elsewhere in the Solar System offer useful options.
Remember that the upper atmosphere of the planets is under bombardment from high-energy galactic cosmic rays (GCR), which results in ‘pair production’ as the kinetic energy of the GCR is converted into mass after collision with another particle. Out of this we get an elementary particle and its antiparticle. Planets with strong magnetic fields become antimatter sources because particles interact with both the magnetic field and the atmosphere. Sinha’s harvester would be an attempt at pair-production that he describes as lightweight and modular. I haven’t seen a paper on this one so I can’t go into useful detail. I’ll hope to do that later.
Storing macroscopic amounts of antimatter for propulsion purposes is the other side of the antimatter conundrum, an issue tackled by Marc Weber (Washington State), who described long antimatter traps in the form of stacks of wafers that essentially form an array of tubes. Storage is an extreme issue because like charges repel, so that large numbers of positrons, for example, generate repulsive forces that magnetic bottles cannot fully contain. Weber’s long traps are in proof-of-principle testing as he tries to push storage times up.
Image: One of Marc Weber’s slides, illustrating principles behind a new kind of magnetic storage trap for antimatter.
Thermonuclear Propulsion and the Gravitational Lens
It’s always a pleasure to see old friends at these events, and I was happy to have the chance to share breakfast with Claudio Maccone, whose long-standing quest to see the FOCAL mission built and flown has come to define his career. But in addition to speaking about the gravitational lens at 550 AU and beyond, Claudio was in Houston to discuss the Karhunen-Loève Transform (KLT), developed in the 1940s to improve sensitivity to artificial signals by a large factor, another idea he has long championed. The idea here is that the KLT has SETI applications, helping researchers in the challenging task of sifting through signals that may be spread through a wide range of frequencies.
Consider our own civilization’s use of code division multiplexing. Mason Peck was also talking about this at the conference — the reason you can use your cellphone in a conversation is that multiple access methods (code division multiple access, or CDMA) allows several transmitters to send information simultaneously though using the same communications channel. Spread-spectrum methods are at work — the signal is sent over not one but a range of frequencies — and you’re actually dealing with a combination of many bits that acts like a code. If we’re using these methods, perhaps a signal we receive from an extraterrestrial civilization may be as well, and perhaps the best way to unlock it is to use the KLT.
I missed Claudio’s session on the KLT but was able to be there for his talk on using the gravitational lens as a communications tool. Beyond the propulsion question, one of the biggest problems with putting a probe around another star is data return. How do we get a workable signal back to Earth? Fortunately, the gravitational lens can offer huge gains by employing the focusing power of the Sun on electromagnetic radiation from an object on the other side of it. Using conventional radio communications would require huge antennae and substantial (and massive) resources aboard the probe itself. These would not be necessary if we fly the needed precursor mission to the distances needed to use the gravitational lens.
Thus we send a relay spacecraft not toward Alpha Centauri but in exactly the opposite direction. Ordinary radio links can be easily maintained. If we tried conventional methods using a typical Deep Space Network antenna and a 12-meter antenna aboard the spacecraft (assuming a link frequency in the Ka band, or 32 GHz, a bit rate of 32 kbps, and 40 watts of transmitting power), we still get a 50 percent probability of errors. A relay probe at the gravitational lens, however, shows no bit error rate increase out to fully nine light years.
I’m moving quickly here and I can’t go through each presentation, but I do want to mention as well Friedwardt Winterberg’s talk on thermonuclear propulsion options. Dr. Winterberg has a long history in researching nuclear rocketry, dating back to the days of Ted Taylor, Freeman Dyson, and the era of Project Orion (which he could not join because he was not yet a US citizen). The Atmospheric Test Ban Treaty of 1963 was one of the factors that put Orion to rest, but Fred has been championing nuclear micro-bombs with non-fission triggers, an idea he first broached at a fusion workshop all the way back in 1956. His most recent paper reminds us of von Braun’s ideas about assembling a huge fleet in orbit for the exploration of Mars:
A thermonuclear space lift can follow the same line as it was suggested for Orion-type operation space lift, but without the radioactive fallout in the earth atmosphere. With a hydrogen plasma jet velocity of 30 km/s, it is possible to reach the orbital speed of 8 km/s in just one fusion rocket stage, instead of several hundred multi-stage chemical rockets, to assemble in space one Mars rocket, for example. .. The launching of very large payloads in one piece into a low earth orbit has the distinct advantage that a large part of the work can be done on the earth, rather than in space.
Exactly how to ignite a thermonuclear micro-explosion by a convergent shockwave produced without a fission trigger is the subject of the new paper, and I’m looking for someone more conversant with fusion than I am to give it a critical reading to be reported here. The basic Orion concept remains in Winterberg’s work with fission bombs replaced by deuterium-tritium fusion bombs being set off behind a large magnetic mirror rather than Orion’s pusher plate.
All Too Little Time
So many papers occurred in different tracks at conflicting times, exacerbated by the need to attend advisory board meetings, so I missed out on a number of good things. I wish I could have attended Kathleen Toerpe’s entire Interstellar Education track, and there were sessions in Becoming an Interstellar Civilization and Life Sciences in Interstellar that looked very promising. I hope in the future the conference organizers will set up video recording capabilities in each track, so that attendees and others can catch up on what they missed.
Several upcoming articles will deal with subjects touched on at 100YSS. Al Jackson is writing up his SETI ideas using extreme astronomical objects, and I’ll be talking about Ken Wisian’s paper on military planning for interstellar flight — Ken and his lovely wife joined Heath Rezabek, Al Jackson, Miles and myself for dinner. The conversation was far-ranging but unfortunately the Friday night restaurant scene was noisy enough that I missed some of it. Miles and I stopped down the street the next night at the Guadalajara, a good Mexican place with a quiet upstairs bar. Great margaritas, and a fine way to close out the conference. Expect an upcoming article from Miles, shown below, on his recent interstellar presentation in a seriously unconventional venue. I’m giving nothing away, but I think you’ll find it an encouraging story.
Can we overcome our preconceptions about extraterrestrial life? Kathleen Toerpe thinks the answer is yes, for we’re moving from the era of ill-informed jokes about ‘little green men’ to a widening appreciation of our place in the cosmos. Dr. Toerpe is the Deputy CEO for Programs and Special Projects at the Astrosociology Research Institute and editor of The Journal of Astrosociology. She also serves as a NASA/JPL Solar System Ambassador, one whose educational efforts on behalf of space exploration have revealed that the younger generation is familiar with and inspired by the subject, a fact that gives this essay its welcome patina of optimism. The recent hearings on SETI in the U.S. House of Representatives show that, for some at least, old attitudes die hard, but ongoing research into astrobiology and SETI is likely to make the ‘giggle factor’ seem positively prehistoric within our lifetimes.
by Kathleen D. Toerpe, PhD
Flip through any newsfeed these days, and it seems that humanity is experiencing an extraterrestrial renaissance. No, I’m not talking about the reboot of the Star Wars franchise, though that reawakening has been long overdue. Rather, I’m referring to the deservedly serious discourse in both the popular and scientific press over the search for extraterrestrial life (henceforth, shortened to “ET” – with both apologies and credit to Mr. Spielberg).
Two prominent examples here make my point.
On May 22, 2014, NASA released a free downloadable eBook edited by SETI social scientist, Douglas A. Vakoch, titled Archaeology, Anthropology, and Interstellar Communication. This fascinating book (which consumed much of my attention the recent Memorial Day weekend) examines the multilayered and interdisciplinary approaches that social scientists employ to anticipate how we might communicate with intelligent beings from another planet. Hearkening to analogs in Mayan hieroglyphs, music theory, Neanderthal research, and decoding extinct Earth languages (among several other fascinating analogs), this compilation of conference presentations teases out the seemingly intractable challenges of decoding and interpreting a message sent from ET and the possibilities of composing our own message in response.
A day earlier, on May 21, 2014, Seth Shostak and Dan Werthimer, two of SETI’s most eminent radio astronomers, testified before the House Committee on Science, Space, and Technology about “Astrobiology and the Search for Life in the Universe.” The hearings focused on the progress made by radio and optical astronomy in detecting extraterrestrial life in the universe, and followed a similar hearing in December of 2013 that focused on the search for alien microbial life. Both Shostak’s and Werthimer’s prepared remarks thoroughly updated the House Committee on the rationales for the search, the search modalities, and the successes, challenges, and future direction of SETI investigations: atmospheric investigations into exoplanetary biochemical signatures, optical SETI recording intermittent pulses of light, panchromatic searches canvassing even broader swaths of the electromagnetic spectrum, even eavesdropping on our exoplanet neighbors for inadvertent signal leaks.
Serious science all around. But a final question, posed by the hearing’s Charter, asked the scientists to speak to the “public interest in the topic.” While Werthimer’s written testimony offered examples of SETI-inspired poetry and citizen science projects (the latter not surprising since the solidly popular and successful SETI@home project is headed out of Werthimer’s UC-Berkeley office), Shostak revealed the five-hundred-pound gorilla lurking in the background. This particular gorilla is commonly known as the “Giggle Factor.”
It is the immediate response many people have when the subject of ET and aliens arise. That under-the-breath chortle, that second look as if to say, “You’re really serious about this?” Psychologist and astrosociologist Albert Harrison analyzed it in his 2005 paper, “Overcoming the Image of Little Green Men: Astrosociology and SETI” and warned especially early-career SETI researchers to “be prepared . . . to risk ridicule . . . and public censure.” It was this same attitude that unfortunately earned SETI research that infamous 1979 “Golden Fleece Award” from former Wisconsin Senator William Proxmire. (Proxmire later recanted, but the damage to SETI’s reputation was done.) I suspect that every serious SETI researcher from the earliest pioneers to today’s practitioners has faced their peers’ and even their audience’s giggles. But I’m going to echo Shostak’s optimistic prediction to the House committee on the imminent discovery of ET life, and likewise guess that the Giggle Factor “is going to change within everyone’s lifetime in this room.”
What gives me the confidence to predict the demise of the Giggle Factor?
One simple word. Children.
One of the many “hats” I wear is as a volunteer NASA/JPL Solar System Ambassador. That is an auspicious-sounding way of saying that I present programs on space research and exploration to anyone in my community who wants to listen to me. Schools, scout troops and packs, senior centers, college classes, library programs, astronomy groups, radio interviews, church luncheons are all some of the places where I and my fellow Ambassadors carry the message of outer space to the public. And I’ve heard my share of giggles when I discuss Kepler exoplanetary discoveries, the Mars Curiosity Rover, and astrobiology research. But here’s the thing: the little kids aren’t laughing. Not a giggle. They wiggle and squirm, they want to play with the beach ball-like planets I bring with me, and they always want to know how much longer until snack time—but they don’t giggle. Not a chortle. Not a guffaw. Instead, there are a lot of wide eyes and dropping jaws when I describe the enormity of space and the possibilities of extraterrestrial life.
In a program I created called “Hello Out There!” we cover the science on Kepler and Curiosity and the Voyager probes, then the kids do their favorite part: composing their own messages on a cardboard “Golden Record” that they take home to share with their families. If Doug Vakoch would like to know what the scientists of tomorrow are most interested in telling ET about, it is . . . drum roll . . . their pets! In my informal review of the times I’ve presented this program (and I’m doing it with another 200 or so children this summer!) children want to tell ET about their pets, their siblings, their parents, and their favorite foods. Perhaps not quite the esoteric mathematical or chemical equations many active-SETI or messaging groups discuss sending, but it hearkens back to the more intimate and simply human messaging of the real-life Voyager recordings.
In his analysis on applying the techniques of archaeology to SETI, archaeologist and NASA e-book contributor Paul Watson concluded that we might be trapping ourselves in an “intellectual context” – our inability to overcome our preconceptions about alien life. Perhaps this is where an analysis of the Giggle Factor best finds its final resting place—as a cultural preconception. Even some of the House committee members couldn’t resist the urge to cast SETI in what Shostak earlier in the hearing had referred to as a “punchline.” House members’ questions about Ancient Aliens, Project Blue Book and UFO visitations, and whether or not ET likes the Beatles songs we’ve been sending out in space all seemed sadly discordant with the official formalities of a Congressional committee hearing. The Giggle Factor dies hard for us adults.
Committee Chairman Lamar Smith’s (Texas) comment that “finding other sentient life in the universe would be the most significant discovery in human history” is no melodramatic hyperbole. The sheer discovery of even microbial life will be far-reaching, especially if it provides confirmatory evidence of an independent DNA structure. It is even more difficult to exaggerate the human impact of the discovery of intelligent extraterrestrial life, though as astrosociologists, I and my colleagues try hard to imagine and anticipate it. It would, in Shostak’s words, “calibrate our place in the intellectual universe.” Even finding nothing will be worth the search, since it would reaffirm, according to Werthimer, that “life on this planet . . . is very precious.” Indeed it is, whether or not we ever hear from ET!
Image: Meeting of the House Committee on Science, Space, and Technology about “Astrobiology and the Search for Life in the Universe.” Credit: Library of Congress.
There is serious work to be done to prepare for the likely detection of extraterrestrial life—by both scientists and social scientists alike. Computing power needs to be enhanced to deal with the massive volume of data being acquired; more sensitive land and sky-based instruments are needed to listen and peek in on the cosmos; media protocols to govern public disclosure of a putative signal detection need to be reviewed, revised and updated; public policy regarding ownership of and access to extraterrestrial microbial samples needs to be negotiated; and — my personal research field — more analysis is needed into the readiness of Earth societies and institutions to assimilate the likely knowledge that we are not alone. And this just scratches the surface of our SETI to-do list!
Once exiled to the fringes of legitimate scientific inquiry by the Giggle Factor, the search for extraterrestrial life has gained new momentum, focus, and funding as the search broadens to encompass the search for microbial, in addition to intelligent, life. In the end, it may be the children who lead the way into a new future for SETI. In his opening statement, Committee Chair Smith reminded the high school students in attendance at the hearing that day that one of the hearing’s purposes is “to inspire students today to be the scientists of tomorrow.” And the noticeable lack of giggling in the room was magic to my ears.
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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