Paul Gilster's Blog, page 242

Small Town Among the Stars

As we’ve had increasing reason to speculate, travel to the stars may not involve biological life forms but robotics and artificial intelligence. David Brin’s new novel Existence (Tor, 2012) cartwheels through many an interstellar travel scenario — including a biological option involving building the colonists upon arrival out of preserved genetic materials — but the real fascination is in a post-biological solution. I don’t want to give anything away in this superb novel because you’re going to want to read it yourself, but suffice it to say that uploading a consciousness to an extremely small spacecraft is one very viable possibility.

So imagine a crystalline ovoid just a few feet long in which an intelligence can survive, uploaded from the original and, as far as it perceives, a continuation of that original consciousness. One of the ingenious things about this kind of spacecraft in Brin’s novel is that its occupants can make themselves large enough to observe and interact with the outside universe through the walls of their vessel, or small enough for quantum effects to take place, lending the enterprise an air of magic as they ‘conjure’ up habitats of choice and create scientific instruments on the fly. You may recall that Robert Freitas envisioned uploaded consciousness as a solution to the propulsion problem, with a large crew embedded in something the size of a sewing needle.

Brin’s interstellar solutions, of which there are many in this book, all involve a strict adherence to the strictures of Einstein, and anyone who has plumbed the possibilities of lightsails, fusion engines and antimatter will find much to enjoy here, with nary a warp-drive in sight. The big Fermi question looms over everything as we’re forced to consider how it might be answered, with first one and then many solutions being discarded as extraterrestrials are finally contacted, their presence evidently constant through much of the history of the Solar System. Brin’s between-chapter discussions will remind Centauri Dreams readers of many of the conversations we’ve had here on SETI and the repercussions of contact.

Into the Crystal

At the same time that I was finishing up Existence, I happened to be paging through the proceedings of NASA’s 1997 Breakthrough Propulsion Physics Workshop, which was held in Cleveland. I had read Frank Tipler’s paper “Ultrarelativistic Rockets and the Ultimate Fate of the Universe” so long ago that I had forgotten a key premise that relates directly to Brin’s book. Tipler makes the case that interstellar flight will take place with payloads weighing less than a single kilogram because only ‘virtual’ humans will ever be sent on such a journey.

Thinking of Brin’s ideas, I read the paper again with interest:

Recall that nanotechnology allows us to code one bit per atom in the 100 gram payload, so the memory of the payload would [be] sufficient to hold the simulations of as many as 104 individual human equivalent personalities at 1020 bits per personality. This is the population of a fair sized town, as large as the population of ‘space arks’ that have been proposed in the past for interstellar colonization. Sending simulations — virtual human equivalent personalities — rather than real world people has another advantage besides reducing the mass ratio of the spacecraft: one can obtain the effect of relativistic time dilation without the necessity of high γ by simply slowing down the rate at which the spacecraft computer runs the simulation of the 104 human equivalent personalities on board.

Carl Sagan explored the possibilities of time dilation through relativistic ramjets, noting that fast enough flight allowed a human crew to survive a journey all the way to the galactic core within a single lifetime (with tens of thousands of years passing on the Earth left behind). Tipler’s uploaded beings simply slow the clock speed at will to adjust their perceived time, making arbitrarily long journeys possible with the same ‘crew.’ The same applies to problems like acceleration, where experienced acceleration could be adjusted to simulate 1 gravity or less, even if the spacecraft were accelerating in a way that would pulverize a biological crew.

Tipler is insistent about the virtues of this kind of travel:

Since there is no difference between an emulation and the machine emulated, I predict that no real human will ever traverse interstellar space. Humans will eventually go to the stars, but they will go as emulations; they will go as virtual machines, not as real machines.

Multiplicity and Enigma

Brin’s universe is a good deal less doctrinaire. He’s reluctant to assume a single outcome to questions like these, and indeed the beauty of Existence is the fact that the novel explores many different solutions to interstellar flight, including the dreaded ‘berserker’ concept in which intelligent machines roam widely, seeking to destroy biological life-forms wherever found. We tend to think in terms of a single ‘contact’ with extraterrestrial civilization, probably through a SETI signal of some kind, but Brin dishes up a cluster of scenarios, each of which raises as many questions as the last and demands a wildly creative human response.

Thus Brin’s character Tor Povlov, a journalist terribly wounded by fire who creates a new life for herself online. Here she’s pondering what had once been known as the ‘Great Silence’:

Like some kind of billion-year plant, it seems that each living world develops a flower — a civilization that makes seeds to spew across the universe, before the flower dies. The seeds might be called ‘self-replicating space probes that use local resources to make more copies of themselves’ — though not as John Von Neumann pictured such things. Not even close.

In those crystal space-viruses, Von Neumann’s logic has been twisted by nature. We dwell in a universe that’s both filled with ‘messages’ and a deathly stillness.

Or so it seemed.

Only then, on a desperate mission to the asteroids, we found evidence that the truth is… complicated.

Complicated indeed. Read the book to find out more. Along the way you’ll encounter our old friend Claudio Maccone and his notions of exploiting the Sun’s gravitational lens, as well as Christopher Rose and Gregory Wright, who made the case for sending not messages but artifacts (‘messages in a bottle’) to make contact with other civilizations. It’s hard to think of a SETI or Fermi concept that’s not fodder for Brin’s novel, which in my view is a tour de force, the best of his many books. As for me, the notion of an infinitely adjustable existence aboard a tiny starship, one in which intelligence creates its own habitats on the fly and surmounts time and distance by adjusting the simulation, continues to haunt my thoughts.

Summer Evenings Aboard the Starship

For some reason Ray Bradbury keeps coming back to me. Imagine traveling to the stars while living in Green Town, Illinois, the site of Bradbury’s Dandelion Wine. If Clarke was right that a sufficiently advanced technology would be perceived as magic, then this is surely an example, as one of Brin’s characters muses while confronting a different kind of futuristic virtual reality:

Wizards in the past were charlatans. All of them. We spent centuries fighting superstition, applying science, democracy, and reason, coming to terms with objective reality… and subjectivity gets to win after all! Mystics and fantasy fans only had their arrow of time turned around. Now is the era when charms and mojo-incantations work, wielding servant devices hidden in the walls…

As if responding to Ika’s shouted spell, the hallway seemed to dim around Gerald. The gentle curve of the gravity wheel transformed into a hilly slope, as smooth metal assumed the textures of rough-hewn stone. Plastiform doorways seemed more like recessed hollows in the trunks of giant trees.

Splendid stuff, with a vivid cast of characters and an unexpected twist of humor. Are technological civilizations invariably doomed? If we make contact with extraterrestrial intelligence, how will we know if its emissaries are telling the truth? And why would they not? Is the human race evolutionarily changing into something that can survive? My copy of Existence (I read it on a Kindle) is full of underlinings and bookmarks, and my suspicion is that we’ll be returning to many of its ideas here in the near future.

Tau Zero: The Steps Ahead

by Marc Millis

Recently I asked you, our readership, what you want from an interstellar organization, given the emergence of Kelvin Long’s Interstellar Institute and the pending symposium of the 100 Year Starship Organization. How to sort out which organization does what? I suspect that the 100YSS will start inviting memberships (fee-based) at their Sept 13-16 symposium. Unfortunately, we will not be able to launch our new Tau Zero website until after that, in October, at which time we will finally be able to take on members (yes, it has been a long arduous process). Then you can see exactly what we have accomplished beyond our continuing Centauri Dreams news forum. I have no idea if Icarus Interstellar or the others will invite memberships around that time too. All of us have been open for donations for some time.

To put the available support into context, I did a little hunting to estimate the total funds that have been contributed to all of our uniquely interstellar organizations (does not include the British Interplanetary Society, Planetary Society, etc.). To date, and if my hunting is reliable, the combined contributions to all our organizations total less than $100k. This, of course, does not include the $500k from DARPA to Mae Jemison’s 100 Year Starship organization. Thus, short of having a substantial increase in funding, there is not much to go around for one organization, let alone a handfull of them.

WHAT YOU TOLD US: COMPILED ANSWERS

I compiled and edited your answers about what you want from an interstellar organization, plus some subsequent discussions for your contemplation and feedback. I did include the answers posted from other organizations, where they listed the services they are offering. I did not include ‘motherhood’ statements which are more about subjective consequences (e.g. “bold & inspiring”) than actionable work.

(1) Promotion and Fund Raising. The distinctions between “promotional” and “enabling,” functions, and “a driver for interstellar flight,” were raised, with the further suggestion that different organizations take on different functions. The suggestion included a recommendation that Tau Zero pursue only the “enabling” functions.

(2) Information: A common theme from the majority of answers, was to have easy access to the most relevant and reliable information. This includes:

– Free (or at least low-cost) journal of interstellar issues and progress (peer-reviewed), the one, go–to, source of emerging information. This includes more than just spacecraft ideas. It should also cover societal implications and the effects of ancillary developments (such as extended human life spans, hibernation, artificial intelligence, and trans-humanism, energy prowess, extinction hazard probabilities, etc.).

– Anthologies that compile the best papers of the past (again covering the full span of relevant topics).

– Detailed books on the key technology options, at a level of detail where the assertions from various studies can be checked against reliable information.

(3) Guiding Scenarios: To provide some context for “how do we get from today to the era of star flight?,” create hypothetical scenarios of the events (technical and societal) that would eventually lead to interstellar missions. There is more than one scenario to create:

– Extrapolating the present rate of progress (technical and societal) till the first mission. Note: Three different studies estimate 2-centuries in this scenario.

– Responding to an impending threat to humanity’s survival.

– Possible technological progress if money and societal support were not limits.

– Implications from the discovery of propulsion physics breakthroughs.

(4) Making Progress: When it comes to making progress (given the information, above, is available), the following statements were made:

– Staged progress where approaches at different levels of technical maturity are treated differently. Where technological progress is nearing implementation, conduct detailed system-level analyses that could lead to implementation plans. For items needing laboratory verification, perform experiments. Items whose feasibility is still uncertain should be treated as basic research, but where it is desired to present some sort of estimate of their viability.

– Want to see “concrete achievements,” not just plans.

– Want “well led projects,” not just visionaries (I’m not sure exactly what is meant here, since I can interpret the statement in more than one way).

– Educational opportunities (many variations on this possible).

– Conducting Mission-Vehicle Studies [The prime activity of Icarus Interstellar]

– Funding individual proposals with clear selection criteria.

(5) Institutes: Both Mae Jemison, of the 100 Year Starship organization, and Kelvin Long each want their own interstellar Institutes. How will they determine who to involve, and how will they get those people to relocate to their central institute? How many people would this involve? How much will it cost? Would its higher costs pull resources away from all the other activities to become the only activity? What services will these institutions offer for the rest of us (those who are not in the institute)?

(6) Symposia and Workshops: Although this was not mentioned in the comments, it has been discussed before. What I would like to hear from our readership is: How frequently do you want them? What do you want to get out of such events? Do you want presentations to be pre-filtered to ensure quality, or do you want full openness? Is it worth having symposia if no potential sponsors are in the audience? How much of a registration fee are you willing to pay?

(7) Inclusivity and Participation: The notion of letting a broad audience participate is a recurring theme. The challenge includes finding worthy tasks for the various skill levels of our audience, and then gleaning the progress made.

ESTIMATED RESOURCES REQUIRED

The following estimates are based on my experiences at NASA and on lessons learned in the course of creating the Tau Zero Foundation. Your mileage might vary. I’m providing these estimates to give you and idea of the relative difficulty of these tasks, and so you will know how much funding any organization will need before being able to offer such services.

(1) Promotion and Fund Raising. For nonprofit organization, a common advice is to allocate 20% of your total funds to fundraising. In other words, if the organization needs $80k to perform its duties, you need $20k just to raise $100k of funding. I have only started to learn about nonprofit fundraising since 2010, and still have a lot to learn. Prior to that, my NASA affiliation made it illegal for me to raise funds actively for Tau Zero.

(2) Information: With our network of practitioners, this is the primary function that Tau Zero has been doing, so our estimates here are fairly accurate:

– Centauri Dreams news forum: This is virtually a full-time job for one person [Paul Gilster], plus it relies on several knowledgeable volunteers to scout for meaningful source material. On this I must share that I am impressed with how much information Paul can process and how frequently he can write. I’m not sure what it would take to provide this service if starting over from scratch.

– Social Network Presence: Here are some of the social networks that Tau Zero has been able to keep up, due to the continuing volunteer services of Larry Klaes. This does not require a full-time position, but it is definitely a serious commitment. My thanks to Larry for helping spread our news via these other organizations:

Interstellar Travel (Tau Zero Fan Page)

Icarus Interstellar

Project Hyperion (an Icarus Interstellar project)

Passionate Universe

Space-Time Travel

Paul Gilster also maintains a Twitter presence as @centauri_dreams.

– Interstellar Journal (free or at least low-cost) (peer-reviewed): Right now, we’ve been relying mostly on the Journal of the British Interplanetary Society since it already exists and has the staff to perform the required functions. If you have access to a university library which carries this journal, you can visit and read articles without having to pay the annual subscription.

To create a new journal would require at least one full-time editor/manager, a staff of part-time help to process submissions through review, revisions, and properly formatted and copyright manuscripts (and maintain the website), and a network of willing & able reviewers who do not have conflicts of interest about what they are reviewing. A rough dollar estimate to provide such a ‘free’ and quality journal would be about $200k annually.

In my personal experience, the hardest part about doing this (even with ample volunteers) is to find qualified reviewers without conflicts of interest. The interstellar community is still relatively small, and although there are many enthusiasts, most of those are not fully qualified. The number of qualified reviewers is small enough that most already know each others’ works and often have conflicts of interest. between them. A double-blind review might solve the conflict of interest problem, but again, since the community is small, it is pretty easy to guess whose paper you are reviewing. Other qualified reviewers could be drawn in from related fields, but we would probably have to offer a small honoraria to get them to review papers that are not within their fields of interest.

– Anthologies that compile the best papers of the past (again covering the full span of relevant topics). As much as I like this idea and would like to see it happen, the challenge again is finding the people who are qualified and impartial that will, indeed, pick the “best” papers, not just their favorite papers. Right now, this is happening only when individuals in our community have enough passion, time, and material to work from. I applaud those who have done, or are attempting such work.

– Detailed books on the key technology options: To assemble a book at this level is a 2-3 year endeavor requiring at least ½ time lead editor, plus a team of authors who can write the detailed chapters spanning the topic. Since this function can fall within the scope of a researcher’s day job, there is a possibility of getting such books written with only minor funding.

The difficulty we have found is to find enough willing experts to write impartial and instructive material amidst the more common advocacy papers. Also, I am encountering difficulty when discussing books with publishers since many seem to be waiting for the electronic rights issues to be resolved first… or so that is what I’m hearing.

– Library of open technical problems that need to be solved: I like this idea so much that we’ve already been working into on our new Tau Zero website. The challenge here is distilling the key issues from all the literature, and then categorizing them so that it is easy for a newcomer to find what they are looking for. Right now, we have a backlog of notes and references that will still take hours of labor to go through, convert, and post into our list. This is something suitable for volunteers at the skill level of undergraduate students.

– Library of reference missions: I like this idea too, and know that Icarus Interstellar is creating these. What I do not know yet – and this gets back to the journal and review challenges –is the level of fidelity and impartiality of those mission/vehicle reports. Historically, before Icarus, there was a tendency in our community to devise mission and vehicle studies to promote a preconceived solution, rather than conducting a requirements-driven, system-level study that is not biased by a favorite power or propulsion option. Such biases are just human nature and are quite common in many fields — Freeman Dyson calls this the ‘Problem of Premature Choice.’ A mitigating strategy to this “premature choice” phenomenon, absent of a team of unbiased, qualified reviewers, is to (1) take all of these studies with a healthy dose of skepticism, and (2) focus on the weakest link of their system to identify what problems still need to be solved (It is common in prior studies to skimp on the assessment of realistic heat rejection and realistic magnetic nozzles). In other words, convert their weakest links into key, next-step tasks… and make progress on those tasks.

(3) Guiding Scenarios: I really like this idea. I will find a way, when we can, to work this into Tau Zero’s activities. This was not already a part of our plans. Off the cuff, I would imagine needing some discussions amongst of our sci-fi authors to kick around possibilities, and then volunteers to distill those discussions into hypothetical scenarios. Each scenario will likely require the same level of effort as a journal paper, but with less rigor, since it is only a prediction. Another option is to run a contest to invite scenarios from our readership. The challenge in that case would be to assemble the review team, support staff, and lead. Provided we had a lead, I consider this a feasible low-cost, mostly volunteer effort. Again, considering that these scenarios will be attempts to predict the future, they should be taken as possibilities, rather than definitive plans.

(4) Making Progress: This is the other area where I’ve aimed Tau Zero to support. Right now, absent of funding to support research, all the progress being made is from our community, where those individuals take on the work themselves to make progress in their area of specialty. At Tau Zero we have been able to forge collaborations to avoid redundancy and to fill niches so that these individual works will have more impact overall. Considering the number of non-redundant and relevant publications that have been forthcoming (technical, science-fiction, journalistic, and artistic), I think our community is doing well. I would like to think that Tau Zero has boosted this, but there is no way to measure it. For example, I have no idea if David Brin’s new novel, Existence, (science-fiction that touches on many issues raised by Tau Zero), was influenced by Tau Zero. Brin is in our network or practitioners, but I’ve not discussed this with him.

When it comes to progress, the other tactic Tau Zero promotes (in addition to the cited collaboration, above), is to focus on the next-step detailed questions instead of advocating a particular solution. This is where Tau Zero differs from others in the community. Several others want to promote their solution and get that solution funded at levels sufficient to launch missions. This includes solar sails, beamed energy sails, nuclear rockets, and nuclear fusion rockets. It is my personal and professional opinion that (1) There is not yet enough prospective funding to support this strategy (requires at least 10′s of millions for any real implementation progress), and (2) It is premature to down select to ‘the’ solution until after we have a more accurate definition of the problem, requirements, and promising technical options.

Regarding educational opportunities, we are collaborating with the Ohio Aerospace Institute to set up graduate student projects, where the student, university, and Tau Zero collaborate to purse a grant for that student to work on a challenge within Tau Zero’s interest. More on this as it develops. To really pull this off would require $500k annually, but we are first seeing what we can do on crumbs.

If there were enough funding to sponsor targeted research, here is how Tau Zero would handle it. In prior estimates, we concluded that a reasonable annual budget to sponsor a research solicitations would be $6M:

– Convene a team of sponsors and practitioners to devise and agree on selection criteria.

– Invite proposals for short-duration tasks (1-3yrs duration) and rank them per the selection criteria just devised.

– To the limit of available funding, select a suite of divergent options from the top-scoring set. By “divergent” I mean that different approaches are supported (diversified portfolio) rather than having all the research cover the same approach.

– Host a symposium to review the findings when that research is done, and refine the next solicitation based on the lessons learned from the prior findings and symposium.

– Repeat that process until enough viable technology has accrued to make interstellar missions possible within the constraints of society’s available support.

(5) Institutes: It has been my experience from watching the creation and fate of other institutes that institutes do more to serve their founders than to serve the community. Regardless, this function still faces the challenges of being able to recruit and successfully manage a fitting team. Rough cost estimates for this sort of approach – absent of the actual research – is about $1-2M annually. Typically, the ‘faculty’ of such institutes are then required to seek additional grants from other sources for the actual topic progress.

Furthermore, it is my professional opinion that the skill set to answer the challenges of interstellar flight are still too fledgling to merge into one institute. Star flight is more than just the vehicle and propulsion. It includes the societal factors, and consideration of a number of specialties that are still emerging, such as synthetic biology, transhumanism, and the pending ‘singularity’ of artificial intelligence. It is because of this widespread and fledgling nature that Tau Zero is pursuing the graduate project idea that is open to all universities.

(6) Symposia and Workshops: This is a necessary function to regularly inform the community of progress, provide opportunities for face-to-face interactions, and invite new participants. Given how long it takes to create new content, It is my professional opinion that symposia should be spread 2 to 3 years apart. The actual costs of hosting a symposium can vary dramatically based on sponsorships, registration fees, and attendance. As a minimum, it requires the full time labor of 2 people for at least a year to assemble a meaningful event.

Due to the difficulty of finding that labor and the over-abundance of symposia and conferences at which interstellar work can be discussed, Tau Zero has no plans to conduct workshops. Instead, we will participate in others’ events as able.

(7) Inclusivity and Participation: The challenge includes finding worthy tasks for the various skill levels of our audience. The discussion forum in Centauri dreams gives our readership the opportunity to participate in discussions. These discussions are moderated to filter out inappropriate comments. The next level of participation is volunteer help. I already have more offers for volunteer help than I can manage. It requires a lot of work to create, assign, and then utilize volunteer tasks. If any of you are willing to manage our Tau Zero pool of volunteers ( ≈ 4-dozen) and are willing to do this as a volunteer for a while, please let me know. This is a job that requires people skills, not engineering or science.

CLOSING COMMENTS

To refresh your memory, my cohorts and I founded Tau Zero to find and forge collaborations amongst genuine pioneers and then share that progress broadly via Centauri Dreams and other publications. Rather than advocating specific vehicles, technologies, or missions, we want to find and encourage progress over the span of options. We also want to make sure we have a realistic set of requirements and constrains (i.e. understanding the problem) before devising ‘the’ solution. Our progress is largely based on the work of our network of practitioners; scientists, engineers, educators, writers, and artists, who work on these topics on their own, but collaborate via Tau Zero to avoid duplication of effort and to find the needed skill mix. In the near future we will debut our new “Discovery Log” – a repository of facts related to interstellar flight, covering these categories:

- Humanity’s Journey

- Destinations

- Getting there.

The services we offer will be articulated in that new website, along with the opportunity to become “members” whose fees grant members access to exclusive information and discounts on Foundation merchandise.

There have been some overtures between some of the organizations to collaborate, to at least avoid redundancy. To help all of these organizations serve you, please add your comments in the discussions. Are these activities what you really want? Which of these do you want first, and most? Which do you think will result in the most progress considering the limited funding? Offer suggestions for where to get the funds and support to your most desired functions.

Ad Astra Incrementis,

Marc Millis

———–

Customer Feedback from the Discussions

Marc Millis August 10, 2012 at 13:43

“Who do ya call?” Dear readers, Are getting confused as to who is doing what and why there is a proliferation of interstellar flight groups?

- British Interplanetary Society

- Tau Zero Foundation w/ Centauri Dreams

- Peregrinus Interstellar

- Icarus Interstellar

- 100 Year Starship Organization, and now..

- Institute for Interstellar Studies.

Rather than advocate our own, I want to take this opportunity to ask YOU, our readership: What do YOU want an interstellar organization to do? And when answering, keep in mind that none of these groups has “serious” money. The bulk of work is till subsidized by volunteered labors of love.

Tell us, all of us, Where are your preferences? What services do you need?

Bob Steinke August 10, 2012 at 15:14

I think one valuable thing that interstellar organizations could do is build up a library of reference mission designs and open technical problems.

Beyond that, if there is any preliminary experimental work that is within their capabilities like the Planetary Society’s work on solar sails.

Interstellar Bill August 10, 2012 at 20:46

We need advanced, graduate-level textbooks on each propulsion option

1. Laser sail

2. Advanced Ion

3. Nuclear Electricity for Space (every non-fusion method from radio isotopes to full scale fission reactors

4. Fusion

We also need anthologies of already-published, specialized interstellar papers. Both IEEE and BIS could alone do great anthologies.

A textbook with one chapter each on these is far too introductory for the dear readers of this blog.

Greg August 10, 2012 at 23:47

“What do YOU want an interstellar organization to do? And when answering, keep in mind that none of these groups has “serious” money. ”

Excellent question Marc, personally I would like to see a staged approach analysis to possible interstellar propulsion solutions. I think if a site could show a stage 1 analysis of possible technologies as well as theoretical physics giving its likelihood between a 1 and 10, 1 being next to impossible 10 being highly likely. It would simply be a group of researchers giving their best guess or analysis of a technology/theory and if it would be feasible or not.

An example is this article on the Giant Casimir effect,

http://www.technologyreview.com/view/...

using meta-materials to possibly amplify the Casimir effect. Between 1 and 10 what is the likelihood this is a possibility and if this could be worth pursuing as a means for energy production or propulsion for interstellar travel.

Stage 2 could be a more detailed analysis of technologies. With stage 3 possibly moving to testing in a lab.

It would be nice to cut through the impossible stuff and speaking for myself, see what may get through.

Jean-Pierre Le Rouzic August 11, 2012 at 6:22

To contribute with my own answer to Marc’s question: What I wait from an organization is any concrete achievement, even if small. Like Bob Steinke, I found Planetary society’s solar sail design and launch attempts to have lots of merits. If someone wants to search (as Paul proves daily) there are valuable scientific papers, but for every good paper there are tons of s**t papers, often using arcane physics concepts to propose what is basically perpetual movement machines. There are already many students that are interested by interstellar concepts (f.e. see what F. Loup did). What we need is not visionaries, there are already some very impressive people and it’s good to talk about them, but we now need project leaders with common sense and attention to details and engineers. We need people able to understand that to build interstellar probes, we have to demonstrate concepts validity and how it could be useful by some aspect to humanity in short term.

Marc: What you can do without money is set a call for realistic interstellar proposals with positive impact on today’s life, with a team of volunteers to select a few very interested works with clear selection criterion. You don’t need to propose a price to recruit volunteers and contributors, many organisations only propose fame and it works (IEEE/Arthur B. Guise Medal (fire protection engineers)). Some even do not propose fame (scouts).

Astronist August 11, 2012 at 10:10

Marc Millis wrote: “What do YOU want an interstellar organization to do?”

To my mind, possibly the most urgent task is to develop and publicise a scenario in which we actually get to do interstellar travel, starting from the present day. Why urgent? Imagine that we start discussing interstellar travel with a member of the large majority of people who are not, for whatever reason, excited by the prospect. What will be on their minds? Overpopulation: we must reduce the world’s population. Climate change: we must give up an energy-intensive lifestyle (see Tom Murphy’s “Do the Math” blog for a diet of pessimism on this point, thus directly contradicting any chance of a starfaring future, given the enormous energy demands of interstellar travel). World hunger: we must abandon spaceflight and spend the money on feeding the poor instead. Militarism: we must abandon spaceflight because all it’s doing is spreading evil American militarism and greedy anti-human capitalism into space (the position of the Global Network Against Weapons and Nuclear Power in Space, and of its sociologist supporters who came to talk at the BIS a couple of years ago).

In other words, I detect a general mood of antipathy towards the value system of growth and progress, which would basically shut down space technology and economic growth if it could, and impose a competing value system based on values of being contented with what one already has and renouncing the accumulation of more material possessions, as well as halting progress towards such things as artificial intelligence, genetic engineering and nanotech.

Clearly, the market is on our side: people generally place a higher value on their comfort and on having the latest gadget than on ideology, particularly self-effacing ideology, and the market is great at driving forward economic and technological progress. But I still think we would be well advised to put at the heart of our message to the broader world a reasoned explanation of why growth and progress are still good, why their benefits outweigh their risks, why climate change, peak oil and nanotech are not about to destroy us, and why the interstellar enterprise is not merely a juvenile-minded hobby that we happen to want to indulge in at everyone else’s cost, but the logical result of the growth of civilisation in a way which benefits everybody.

Stephen

Oxford, UK

Kelvin F. Long August 11, 2012 at 12:54

Marc Millis wrote:

“…Rather than advocate our own, I want to take this opportunity to ask YOU, our readership: What do YOU want an interstellar organization to do? ”

My top five answers:

1. Demonstrate both theoretical and experimental progress towards the long term vision, utilizing rigorous scientific techniques, across the spectrum of options, producing tangible benefits and real technologies.

2. Demonstrate inspired leadership, good mangement and governance in an open, transparent and responsible way.

3. Initiate bold and exciting projects and programs which inspire the world, swell our numbers, and produce more reliable studies.

4. Work together, co-operatively and co-ordinatively, for common purpose, shared ambitions and increased national and international impact, in a way that rises above politics and human behaviours.

5. Break down barriers to participation, knowledge, and belief in the seemingly impossible, by the creation and facilitation of opportunity through education and outreach, using positive-optimistic motivation.

Kelvin F. Long

Jack Crawford August 11, 2012 at 15:51

At this early juncture I think Tau Zero needs to differentiate between being a promoter, an enabler, and a driver of interstellar flight. Of these three things I think acting as an enabler is the easiest to do on a tight budget because it can be done by volunteers as a labor of love while research and public awareness cost money. As an enabler, Tau Zero’s role is to act as a compiler and distributor of knowledge. By acting as a venue for the exchange of information, such as a a free peer reviewed online journal, the Tau Zero Foundation can be a safe haven for scholarly writing, review papers, and general education.

Currently, the literature for interstellar studies is greatly scattered which makes finding and following the literature trail difficult. This impedes research. Review papers can address this and another problem: the academic pay wall to information. Think of the audacity of having to pay $80 for a 10 page paper on the subject you are interested in only to find the paper doesn’t deliver what the abstract says was in the paper. This is our enemy: inaccessible and poor quality information. Help from academia is not coming any time soon so the burden for progressing interstellar studies is on the citizen scientist and engineer, but someone has to give them the tools to succeed. Tau Zero can do this. Important but obscure information can be compiled and rewritten for public consumption. Code for common numerical calculations can be made freely available. Scholarly articles can be held to a higher standard. Proper education articles aimed at the armchair enthusiast can also be written. All you need are volunteers to write and some editors.

~ Jack Crawford

spaceman August 12, 2012 at 3:08

The aforementioned interstellar organizations will– certainly in a more realistic manner than does the film industry– definitely go along way as it pertains to keeping the grand goal of crossing the light years alive. Assuredly, new ideas will originate from these groups and existing ideas will be further refined as technology advances.

As a lover of puzzles, I would like to see the interstellar dream presented as the ultimate puzzle– a puzzle that combines several branches of science both natural and social. So geniuses put down your NYTimes Saturday crossword, which of you has what it takes to crack this one? What could be more challenging and exciting, more important in terms of ensuring human species survival than solving this intricate conundrum of epic proportions?

But it’s like what a friendly fellow at a recent singles party said to me: “When I was your age I used to think that if I waited around it would all fall into place. The right woman would just enter my life…but that’s unlikely. You have to get out there and do the hard work of finding her.”

How true. I can and do imagine her. I think about the pros and cons of getting involved with her, but at the end of the day I know the imagining will only get me so far. He’s right, I have to get out there more and test the waters. Same is the case with interstellar societies…they are a great resource for thinking about, for example, which candidate propulsion systems might work best as well as other aspects of deep spaceflight. Imaginative interstellar groups are crucially important in terms of developing ideas on how it might be possible to effectively span the immense interstellar gulf, but eventually they—like me, will have to get out there and test/implement the ideas in the real world.

Ric August 13, 2012 at 4:10

Seems to me that the Interstellar Institute already exists: Zero Tau. So why not slightly expand the scope of the Zero Tau website and merge the Intersteller Institute topics into it?

Adam Crowl August 13, 2012 at 7:29

An interstellar organisation with the aim of achieving interstellar flight needs to look at the many propulsion suggestions made over time and the broader pre-conditions needed to make the various scenarios happen. For example, what kind of society can make a large multi-stage fusion-propelled probe happen? What economic pathway will make that feasible? And how will it transform life for the rest of humanity?

Or what would lead to huge multi-terawatt lasers able to push sail-craft to half the speed of light? Would powering such devices lead to abundant solar-power systems for human-kind?

Being able to live in space for decades at a time would have implications for recycling and food-processing in a multitude of ways, surely a vital concern on a crowded Earth. By promoting development of minaturised industry, food-production, medical facilities and scientific equipment – all applicable to humans thriving in other star-systems – then we’d be sparking unimaginable leaps forward for everyday life on Earth.

Kick-starting the economic infrastructure needed to develop the solar-system will be another area for the interstellar organisation. For example, Philip Metzger (and his NASA colleagues) have some interesting proposals for boot-strapping space-industry via the Moon’s resources.

Well worth exploring further the whole idea of teleoperated, semi-self-replicating remote facilities on the Moon.

What we need to do is get away from the vision of the one-shot effort. Interstellar involves everyone and could well transform the world.

A Circumbinary Planetary System

Among the more interesting items coming out of the XXVIII General Assembly of the International Astronomical Union (IAU) in Beijing is news of a circumbinary system containing two planets. We’ve seen circumbinary worlds before — Kepler-16b is a planet orbiting not one but two stars, as are Kepler-34b and Kepler-35b. There was a time that the idea of a planet orbiting two stars, as opposed to orbiting one or the other of two stars in a binary system, seemed unlikely. Now we have a multiple-planet system in exactly this configuration.

It’s an interesting one, too. Some 4900 light years from Earth in the constellation Cygnus, the two stars orbit each other roughly every 7.5 days. One of the stars is fairly similar to the Sun, though about 15 percent less bright, while the other is an M-dwarf about a third of Sol’s size and 175 times fainter. Of the two planets, one — Kepler-47b — is three times the diameter of Earth and eight times its mass, orbiting the twin stars every 49 days. The outer planet — Kepler-47c — catches the eye because it orbits the stars every 303 days, placing it within the twin stars’ habitable zone.

To be sure, this looks to be a gas giant a bit larger than Uranus in size, with about 20 times the Earth’s mass. While not itself a candidate for habitability, its placement allows speculation that an exomoon around it could potentially hold life. The diagram below relates the Kepler-47 system to our own, with the two newly discovered worlds shown for comparison:

Credit: NASA/JPL-Caltech/T. Pyle.

Jerome Orosz (San Diego State University), lead author of the study, notes the tricky nature of the observations that revealed the two worlds:

“In contrast to a single planet orbiting a single star, planets whirling around a binary system transit a moving target. The time intervals between the transits and their duration can vary substantially, from days to hours, and therefore the extremely precise and almost continuous observations with Kepler space telescope were fundamental.”

As this IAU news release notes, the loss of light caused by the eclipse is tiny. While Venus, for example, blocked out about 0.1 percent of the Sun’s surface during its most recent transit in June, Kepler-47b and c blocked out 0.08% and 0.2 percent respectively. Ground-based observations at McDonald Observatory (University of Texas at Austin) backed the Kepler data as the researchers studied the properties of this system. Michael Endl and colleagues studied the binary star with the 9.2-meter as well as the 2.7-meter instruments at McDonald.

“It’s Tatooine, right?” said Endl. “But this was not shown in Star Wars.” The astronomer was referring to the highly variable daylight that would fall upon a planet orbiting two stars. In fact, measurements of the stellar orbits told Endl’s team that daylight on the two planets would vary by a large margin over the 7.4 day period that the stars needed to complete their orbits. A closer look at the McDonald Observatory work can be found in this UT-Austin news release.

Meanwhile, planet hunter Greg Laughlin (UC-Santa Cruz) has this to say:

“The presence of a full-fledged circumbinary planetary system orbiting Kepler-47 is an amazing discovery. These planets are very difficult to form using the currently accepted paradigm, and I believe that theorists, myself included, will be going back to the drawing board to try to improve our understanding of how planets are assembled in dusty circumbinary disks.”

Indeed. We now know that close binaries can host not just single planets but complete planetary systems. The paper is Orosz et al., “Kepler-47: A Transiting Circumbinary Multiplanet System,” published online in Science August 28, 2012 (abstract / preprint).

The Magicians of Confidence

Centauri Dreams regular Al Jackson responded to yesterday’s post about Neil Armstrong with reminiscences of the Apollo program, but because the first of these ran as a comment to the story, I was afraid a lot of readers wouldn’t see it — we have far more subscribers through RSS than any other medium, and many of them do not see the comments. When Al submitted a second comment, I decided to merge them into a single post here. The author of numerous scientific papers and a widely known figure in the interstellar community, Al saw the Apollo program up close as astronaut trainer on the Lunar Module Simulator. Here he talks about Armstrong and Aldrin and the antics of the crew that followed Apollo 11.

by A. A. Jackson

I spent almost 4 years in the presence of Neil Armstrong and Buzz Aldrin. I came to the Manned Spacecraft Center (MSC) in 1966, where I was placed as a crew training instructor. I had degrees in math and physics at that time. Seems engineers were pressed into real engineering work or had been siphoned off into the DOD. Spaceflight attracted a lot of physicists who could be put to work on all kinds of stuff.

It’s funny, I met Buzz first, I think as early as 1966. At MSC in those days I used to be in Bldg. 4 (my office) or Bldg. 5 (the simulation facility) in the evenings. Sometimes we worked a lot of second shift and I was unmarried at the time with a lot time on my hands. Anyway Buzz would come to Bldg. 5 to practice in a ‘part task’ trainer doing manual rendezvous , something he had pioneered. So I kind of got to know Buzz, but I can’t remember much but small talk and later talk about the Abort Guidance System which was my subsystem.

Image: Al Jackson (facing the camera at the main console of the Lunar Module Simulator) performing a checkout of LMS systems with his colleagues. Credit: A. A. Jackson.

When the Lunar Module Simulator (LMS) got into operation I started seeing Neil, but never talked to him much. Of all the Apollo crews Neil and Buzz were the most quiet. I remember the time when we had them in the cockpit from about 8am to nearly noon and they had not said anything for like 3 hours, someone wondered if we ought to go up and check if they were all right! I do remember Neil from the trips to MIT and TRW, to go to briefings on the Primary Guidance and Navigation and the Abort Guidance System.

I had seen Buzz do a little ‘chalk talking’ about technical stuff, but on the TRW trip Neil got up and gave a short seminar about rendezvous in orbit, some math stuff and all. He really knew his stuff. I remember being kind of surprised because I knew about Buzz’s doctorate in astronautics, but did not know Neil knew that much engineering physics. I do remember Neil coming to the LMS the morning after the Lunar Landing Training Vehicle crash, I think the backup crew were there, and them asking him how he felt and he said “O I’m just a little sore.” Actually he had bitten his tongue badly.

The Apollo 11 crew were the backup crew for Apollo 8, except for Fred Haise — that crew too could have been first on the moon. I puzzle these days whether Deke Slayton and higher ups arranged that it would be Neil and Buzz or not. All the astronauts I worked with were very unusual and able men… but Neil and Buzz had more than the Right Stuff, they were kind of magicians of confidence. It would be years before the astronaut corps had anyone quite like them.

You know working Apollo, nearly 24 – 7 for five years, in those days we had our heads down in the trenches, so it is strange to think back, a lot of odd things and lore escaped my attention. I was never a diary keeper, but wish I had been. I do remember how seat-of-the-pants everything was. Everything became much more formalized in the Shuttle Era and I was glad I did not stay in crew training for all but 5 years of my tenure at JSC.

It was the Apollo 12 crew who were the most fun. Pete Conrad was the most free spirited man I ever met. He bubbled with enthusiasm and humor, a thinking man’s Evel Knievel. He was an ace pilot who kept us in stitches all the time. Conrad and Bean spent a lot of time in the LMS (I think Neil and Buzz spent the most) and we instructors really got tired of wearing our headsets , so when crews were in the LMS we would turn on the speakers we had on the console since the crew spent most of their time talking between themselves. When Conrad was in the cockpit we had to turn the speakers off, since we would unexpectedly have visitors come by.

The reason why: Conrad, an old Navy man, could string together some of the most creative blue language you would ever want to hear. The main guidance computer aboard both the Command Module and Lunar Module was called the Primary Guidance, Navigation and Control System (PGNCS), but the crews called it the PINGS. Conrad never called it that. I can’t repeat what he called it, but he never, in the simulator called it that. The instructors remembered the trouble Stafford and Cernan caused on Apollo 10 with their language, and we thought lord! Conrad is gonna make even Walter Cronkite explode in an oily cloud! Yet on Apollo 12 he never slipped once, that’s how bright a man he was.

A month or two before Apollo 11 Conrad and Bean were in the cockpit of the LMS and John Young was taking a turn at being the pilot in the CMS (Command Module Simulator). We were running an integrated sim. Young had learned that the CM would be named Columbia and the LM Eagle. Conrad being his usual individualistic self said that must have pleased Headquarters. (Of course Mission Control needed those names when the two vehicles were apart for com reasons).

So Conrad could not resist. He told Bean and Young right then and there that they were going to name the CM and LM two names that I also can’t repeat. Bean and Young had a ball the rest of the sim giving those call signs, but that only lasted one day. Conrad, as you might suspect, never used the language in an insulting way or even to curse something — he was a very friendly and funny man. But it’s so second nature in the military to use language like that, and those Navy men, well, they never said “pardon my French!” Later the three Navy men (Conrad, Bean and Gordon) gave their spacecraft proper Navy names! Remember them?

On Neil Armstrong

“Neil Armstrong may well be the only human being of our time to be remembered 50,000 years from now.”

— J. G. Ballard, “Back to the Heady Future,” Daily Telegraph, 17 April 1993.

If anything, Neil Armstrong was almost too perfect for the role he played. If I had been asked to script the kind of character I’d like to have seen as the first man on the Moon, Armstrong would have walked into the role effortlessly, a quiet, even diffident man who had the courage to ride rockets. Flyers come in all descriptions, but those I used to hang around with in my own flying days (far tamer than any of Armstrong’s, to be sure!) were generally raconteurs, full of improbable tales that could never be verified, jongleurs seasoned in the arts of extroversion.

Not so Neil Armstrong, and therein lies the reason for my own sense of pride in the man and his accomplishment. July 20, 1969 was, inevitably, a hot day in St. Louis. I had driven to Webster Groves that afternoon to watch the moon landing with my future wife along streets that shimmered with heat. A native of the city, I was used to the humidity and it wasn’t because of it that my hands were sweaty. Like so many around the world, I was jacked up and nervous as a cat. We watched the landing to the sound of distant thunder, not learning until later just how pulse-pounding the actual touchdown became, though hearing about computer alarms during the descent made it clear this was one script that hadn’t proceeded precisely by the book.

Later that night, back at my own house after the first steps had been taken on the Moon, I looked at the LEM on TV and knew I was in the middle of history and that someday I would be explaining how it felt to my grandchildren. I slept little that night, my thoughts — now and then turning into dreams — playing the landing sequence over and over again. The next day, which was a Monday if memory serves, I drove downtown to buy tobacco at my favorite pipe shop and saw a huge banner draped across one of the buildings. Its words were simple: ‘We Made It!’ That sense of collective exaltation is something that’s hard to describe to those who weren’t fortunate enough to experience it. It transcended an Asian war and the era’s violent politics.

Image: A time like no other: Collins, Aldrin, Armstrong amidst an exultant crowd in August of 1969.

The details of Armstrong’s life are all over the media — this Washington Post story is a good summary, especially in its comment by James Hansen, who wrote Neil’s biography First Man (Simon & Schuster, 2005). Hansen’s take is that Neil didn’t want any part of what would surely have become blatant commercialism growing out of Apollo 11’s accomplishments. Thus the withdrawal from public life that grew out of the natural instincts of a loner. The analysis helps to explain a man some saw as mysterious and others as mythic.

He was both those things, of course, but like all human beings, he transcended easy description. Armstrong would become the space program’s Garbo, elevated and magnified by virtue of his very untouchability. I wondered last night what his final thoughts were as the end approached. Would he have played over in his mind the dramatic moments of July 20, 1969? Maybe, and that’s how it would probably be scripted in a movie. But it’s just as likely that what he was perceiving in those last moments was deeply personal, a childhood Christmas, perhaps, or a favorite song during flight training, or the face of a woman he loved.

None of us can know how anyone else approaches death, but we are all creatures of bone, sinew and nerve and we live the truest part of our lives in the kind of deep emotional privacy that Neil Armstrong came to exemplify. This quietly dignified man vaulted into prominence only to remind us that great achievement does not have to walk hand in hand with ego. Indeed, Armstrong’s legacy will couple the Sea of Tranquility with the collected bearing of an individual who never elevated himself over others, whose gift of focused passion offers deep truths in the meaning of courage and character.

Magellanic Clouds a Celestial Rarity

The Magellanic Clouds, visible in the southern hemisphere, are two dwarf galaxies that orbit the Milky Way, a fact that has always captivated me. We see the galaxy from the inside, but I have always wondered what it would be like to see it from the perspective of the Magellanics. The Large Magellanic Cloud (LMC) is, after all, only 160,000 light years out, while the Small Magellanic (SMC), its companion cloud, is about 200,000 light years away. Add in the recently discovered Sagittarius Dwarf Elliptical at 50,000 light years from the galactic core and you have three exotic venues from which to gain a visual perspective on the Milky Way, at least in the imagination.

We’re so used to thinking that our solar and galactic neighborhoods are utterly commonplace that it may come as a surprise to learn that the configuration of spiral galaxy and satellite galaxies that we see in the Milky Way is actually quite unusual. New work on this comes from Aaron Robotham (International Center for Radio Astronomy Research and University of St. Andrews), whose team looked for groups of galaxies in something like our own configuration. The data for this effort is drawn from the Galaxy and Mass Assembly project (GAMA), a spectroscopic survey of ~340,000 galaxies using the AAOmega spectrograph on the Anglo-Australian Telescope that builds on and is augmented by earlier spectroscopic efforts.

Image: This image shows one of the two ‘exact matches’ to the Milky Way system found in the survey. The larger galaxy, denoted GAMA202627, which is similar to the Milky Way clearly has two large companions off to the bottom left of the image. In this image bluer colours indicate hotter, younger, stars like many of those that are found in our galaxy. Image Credit: Dr Aaron Robotham, ICRAR/St Andrews using GAMA data.

The effort is interesting because we have never had a good understanding of how unusual the configuration of the Milky Way and its halo really is. The halo should contain the faintest known satellite galaxies because it is so close, and we should be able to study its characteristics to learn more about the galaxy’s formation history, knowledge which can then be extended to other galaxies. According to the paper on this work, simulations have trouble predicting the full distribution of satellite galaxies around the Milky Way halo, especially for the brightest of these, the Magellanics. Satellites in this configuration have been thought to be a rare occurrence.

The new work, presented at the International Astronomical Union General Assembly in Beijing, bears out this conclusion. Think of the halo as the spherical component surrounding the galaxy, which contrasts with the flat disk of the Milky Way. We’re on the cusp of major strides in our studies of galactic halos, because missions like the soon to be launched GAIA will let us measure the properties of 2 billion stars in the Local Group, including samples from all the member galaxies. For now, the Galaxy and Mass Assembly project has produced redshift data that allow Robotham and his colleagues to search for Milky Way Magellanic Cloud Analogs in the halos of galaxies with close companions much like our own.

The results bear out our simulations. The researchers found that only 3 percent of spiral galaxies like the Milky Way have satellite companions like the Magellanic Clouds. In the GAMA data, 14 galaxy systems were roughly similar to ours, but only two turned out to be a truly close match. Many galaxies have smaller galaxies in orbit around them, but few have satellites as large as the two Magellanic Clouds. About the closest matches, the paper has this to say:

Only two full analogues to the MW [Milky Way]-LMC-SMC system were found in GAMA, suggesting such a combination of late-type, close star-forming galaxies is quite rare: in GAMA only 0.4% (0.3%–1.1%) of MW mass galaxies have such a system (a 2.7σ event). In terms of space density, we find 1.1 × 10−5 Mpc−3 full analogues in GAMA (in a volume of 1.8 × 105 Mpc3). The best example found shares many qualitative characteristics with the MW system. The brightest pair galaxy has spiral features, as does the bigger minor companion. The minor companions are ∼40 kpc in projected separation, so not in a close binary formation like the SMC and LMC.

Adds Robotham: “The galaxy we live in is perfectly typical, but the nearby Magellanic Clouds are a rare, and possibly short-lived, occurrence. We should enjoy them whilst we can, they’ll only be around for a few billion more years.”

The paper is Robotham et al., “Galaxy And Mass Assembly (GAMA): In Search of Milky-Way Magellanic Cloud Analogues,” Monthly Notices of the Royal Astronomical Society, Volume 424, Issue 2 (2012), pp. 1448-1453 (preprint).

A Planet Engulfed by a Red Giant?

Polish astronomer Aleksander Wolszczan (Penn State) is best known as the discoverer of the first confirmed planet outside our Solar System. That was back in the early 1990s, when Wolszczan was working with Dale Frail (NRAO), using observations from the Arecibo dish to demonstrate that the pulsar PSR B1257+12 was orbited by two planets. These are relatively small worlds (3.9 and 4.3 Earth masses respectively), and in an era where new planet candidates number in the thousands, it’s easy to forget how striking Wolszczan’s work appeared at the time, and how it gave impetus to the developing exoplanet hunt.

A pulsar planet looks to be an extremely inhospitable place, but learning how planets are distributed among the stars involves studying every conceivable kind of world. Wolszczan’s latest work targets an equally hostile environment, the former habitable zone of a star that has begun expanding into a red giant. The star, BD+48 740, has 11 times the Sun’s radius and is significantly older. Wolszczan and an international team of astronomers have been studying its chemical composition by way of figuring out events in its recent past. Using data gathered at the Hobby-Eberly Telescope (UT-Austin), they discovered that BD+48 740 contains an unusual amount of lithium, an element created primarily in the early days of the universe.

Finding lithium in such high amounts is a flag to the astronomer:

“Theorists have identified only a few, very specific circumstances, other than the Big Bang, under which lithium can be created in stars,” Wolszczan added. “In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet that spiraled into the star and heated it up while the star was digesting it.”

Image: The first evidence of a planet’s destruction by its aging star indicates that the missing planet was devoured as the star began expanding into a “red giant” — the stellar equivalent of advanced age. “A similar fate may await the inner planets in our solar system, when the Sun becomes a red giant and expands all the way out to Earth’s orbit some five-billion years from now,” said Alexander Wolszczan, Evan Pugh Professor of Astronomy and Astrophysics at Penn State and the discoverer of the first planet ever found outside our solar system. Credit: Marty Harris/McDonald Obs./UT-Austin.

The work on BD+48 740 is part of the Penn State-Toruń Planet Search, which specializes in detecting planetary systems around stars more evolved than the Sun. Some 50 red giants are currently known to host planets or brown dwarf companions, some of them (like HD 102272) in multi-planet systems. Although earlier phase sub-giants are found with ‘hot Jupiters’ orbiting them, the more evolved red giants show few planets in close orbits and few planets whose orbit is eccentric.

That makes the discovery of a long-period planet in a highly eccentric orbit around a red giant an interesting find. BD+48 740 is orbited by a planet of at least 1.6 Jupiter’s mass in such an orbit, one the researchers call the most elliptical planetary orbit yet detected around an evolved star. The culprit should be gravitational interactions between planets, and the suspicion is that the missing planet was the cause, its dive into the star giving the outer planet a gravitational boost.

The elliptical orbit of the newly discovered planet is not in itself enough to imply the engulfment of an inner planet. The paper on this work points out that we have studied planetary systems like HAT P-13 b, c and HD 217107 b, c, both systems around main sequence stars in which there is a close-in planet in a nearly circular orbit and a more distant companion in an eccentric orbit. But the lithium abundance in BD+48 740 suggests a missing planet and a recent planet-planet scattering event, one that would have occurred after the star had left the main sequence.

Says team member Eva Villaver (Universidad Autonoma de Madrid):

“Catching a planet in the act of being devoured by a star is an almost improbable feat to accomplish because of the comparative swiftness of the process, but the occurrence of such a collision can be deduced from the way it affects the stellar chemistry. The highly elongated orbit of the massive planet we discovered around this lithium-polluted red-giant star is exactly the kind of evidence that would point to the star’s recent destruction of its now-missing planet.”

The paper is M. Adamów at al., “BD+48 740 – Li overabundant giant star with a planet. A case of recent engulfment?” Accepted at Astrophysical Journal Letters (preprint). A Penn State news release on this work is also available.

Exotic Detections: Wormholes and Worldships

SETI always makes us ask what human-centered assumptions we are making about extraterrestrial civilizations. When it comes to detecting an actual technology, like the starships we’ve been talking about in the last two posts, we’ve largely been forced to study concepts that fit our understanding of physics. Thus Robert Zubrin talks about how we might detect a magsail, or an antimatter engine, or a fusion-powered spacecraft, but he’s careful to note that the kind of concepts once studied by the Breakthrough Propulsion Physics Project at NASA may be undetectable, since we really don’t know what’s possible and what its signature might be.

I mentioned zero-point energy in a previous post because Zubrin likewise mentions it, an idea that would draw from the energy of the vacuum at the quantum level. Would a craft using such energies — if it’s even possible — leave a detectable signal? I’ve never seen a paper on this, but it’s true that one classic paper has looked at another truly exotic mechanism for interstellar travel, the wormhole. These shortcuts through spacetime make space travel a snap. Because they connect one part of the universe to another, you go in one end and come out the other, emerging into another place and, for all we know, another time.

The fact that we don’t know whether wormholes exist doesn’t mean we can’t think about how to detect one, although the authors of the classic paper on wormhole detection make no assumptions about whether or not any intelligent species would actually be using a wormhole. The paper is “Natural Wormholes as Gravitational Lenses,” and it’s no surprise to find that its authors are not only wormhole specialists like Matt Visser and Michael Morris, but physicists with a science fiction connection like John Cramer, Geoffrey Landis, Gregory Benford and the formidable Robert Forward.

Image: A wormhole presents a shortcut through spacetime. Can one be detected? Credit: Wikimedia Commons.

The analysis assumes that the mouth of a wormhole would accrete mass, which would give the other mouth a net negative mass that would behave in gravitationally unusual ways. Thus the GNACHO (gravitationally negative anomalous compact halo object), which playfully echoes the acronym for massive compact halo objects (MACHOs). Observationally, we can look for a gravitational lensing signature that will enhance background stars by bending light in a fundamentally different way than what a MACHO would do. And because we have MACHO search data available, the authors propose checking them for a GNACHO signature.

In conventional gravitational lensing, when a massive object moves between you and a much more distant object, a greatly magnified and distorted image of the distant object can be seen. Gravitational lensing like this has proven a useful tool for astrophysicists and has also been a means of exoplanet detection. But when a wormhole moves in front of another star, it should de-focus the light and dim it. And as the wormhole continues to move in relation to the background star, it should create a sudden spike of light. The signature, then, is two spikes with a steep lowering of light between them.

The authors think we might find the first solid evidence for the existence of a wormhole in our data by looking for such an event, saying “…the negative gravitational lensing presented here, if observed, would provide distinctive and unambiguous evidence for the existence of a foreground object of negative mass.” And it goes without saying that today’s astronomy, which collects information at a rate far faster than it can be analyzed, might have such evidence tucked away in computer data waiting to be discovered by the right search algorithms.

Would a wormhole be a transportation device? Nobody knows. Assuming we discover a wormhole one day, it would likely be so far away that we wouldn’t be able to get to it to examine its possibilities. But it’s not inconceivable that a sufficiently advanced civilization might be able to create an artificial wormhole, creating a network of spacetime shortcuts for instantaneous travel. Matt Visser has discussed a wormhole whose mouth would be held open by negative energy, ‘…a flat-space wormhole mouth framed by a single continuous loop of exotic cosmic string.’ A primordial wormhole might survive from the early universe. Could one also be created by technology?

Civilizations on the Brink

More conventional means of transport like solar or laser-powered sails present serious problems for detection. In Jerry Pournelle and Larry Niven’s The Mote in God’s Eye, an alien lightsail is detected moving at seven percent of the speed of light, its spectrum the same as the star that it is approaching but blueshifted, which is how analysts have determined it is a sail. The novel’s detection occurs with far more sophisticated observatories than we have in our day, when finding a solar or lightsail in transit would be a tricky thing indeed. A fusion rocket, for example, would emit largely in the X-ray range and could be detectable for several light years, but a lightsail is a highly mutable catch.

I remembered reading something about this in Gregory Matloff’s Deep Space Probes (Springer, 2005) and checked the book to extract this:

If ET prefers non-nuclear travel, he might utilise a laser or maser light sail. If the starship is near enough and the laser/maser is powerful enough, reflections from the sail might be observable as a fast-moving and accelerating monochromatic ‘star.’ However, detection will depend on sail shape and orientation as well as other physical factors.

Therefore, it is not as easy to model the spectral signature of these craft as it is energetic nuclear craft. A starship accelerated using lasers or masers may be easier to detect during deceleration if a magsail is used.

Writing in the comments to yesterday’s post, Centauri Dreams reader James Jason Wentworth recalls Larry Niven’s short story “The Fourth Profession,” which has a lightsail detection something like the one in The Mote in God’s Eye:

“All right. The astronomers were studying a nearby nova, so they caught the intruder a little sooner. It showed a strange spectrum, radically different from a nova and much more constant. It got even stranger. The light was growing brighter at the same time the spectral lines were shifting toward the red.

“It was months before anyone identified the spectrum.

“Then one Jerome Finney finally caught wise. He showed that the spectrum was the light of our own sun, drastically blue-shifted. Some kind of mirror was coming at us, moving at a hell of a clip, but slowing as it came.”

Some sails could be truly gigantic, and we can imagine worldships large enough to require sails the size of a planetary radius, which could be detected when near their home or destination stars, but would be hard to find when in cruise. Matloff goes on to suggest that any search for this kind of ship should look near stars from which an entire civilization might be emigrating. A star like Beta Hydri is a possibility, a nearby (21 light years) solar-type star now expanding from the main sequence. This is the longest shot of all, but finding unusual signatures in visible light near a star leaving the main sequence would at least compel a second look.

The wormhole paper is John Cramer, Robert L. Forward, Gregory Benford et al., “Natural Wormholes as Gravitational Lenses,” Physical Review D (March 15, 1995): pp. 3124–27 (available online). See also Matloff and Pazmino, “Detecting Interstellar Migrations,” in Astronomical and Biochemical Origins and the Search for Life in the Universe, ed. C. B. Cosmovici, S. Bowyer and D. Werthimer, Editrici Compositori, Bologna, Italy (1997), pp. 757-759.

SETI: Starship Radiation Signatures

Yesterday we pondered the possibility of detecting an interstellar craft as a new kind of SETI. If the energies needed to drive such a vessel are as titanic as we think, there could be a detectable signature, as Robert Zubrin pointed out in a 1995 paper. Zubrin’s best case in visible light involved an antimatter engine whose exhaust could be detected from as far as 300 light years from Earth. That would cover a huge number of stars, as 100,000 exist within 200 light years of our planet.

I suppose the classic starship detection occurs in Larry Niven and Jerry Pournelle’s 1975 novel The Mote in God’s Eye, where human starfarers using the ‘Alderson Drive’ — which allows instantaneous jumps between stars — detect an alien, laser-pushed lightsail. The starship is a throwback, an older technology that human interstellar methods have long superseded, one that contains a strange, asymmetric alien being, the first extraterrestrial humans have encountered. It’s no surprise to learn that Niven and Pournelle fine-tuned the laser lightsail idea through conversations with Robert Forward, who studied such concepts intensively in the scientific literature.

And then there’s Gregory Benford’s 2006 novelette about an astronomer who begins to suspect the anomalous object he’s looking at isn’t natural. Whereas Zubrin looked at antimatter, fusion, fission and magsails, Benford’s astronomer thinks he’s found something like a Bussard ramjet:

“What you wrote,” she said wonderingly. “It’s a…star ship?”

“Was. It got into trouble of some kind these last few days. That’s why the wake behind it – “ he tapped the Fantis’ image – “got longer. Then, hours later, it got turbulent, and—it exploded.”

She sipped her coffee. “This is…was…light years away?”

“Yes, and headed somewhere else. It was sending out a regular beamed transmission, one that swept around as the ship rotated, every 47 seconds.”

Her eyes widened. “You’re sure?”

“Let’s say it’s a working hypothesis.”

The story is “Bow Shock,” which ran in Jim Baen’s Universe and is reprinted in Benford’s new collection Anomalies. Benford speculates that synchrotron radiation in the bow shock of a magnetically screened starship would be detectable at microwave and radio frequencies, and perhaps an easier catch than the torch of Zubrin’s antimatter spacecraft from a great distance. Ralph, Benford’s astronomer, had been examining what he thought was a runaway neutron star, ‘a faint finger in maps centered on the plane of the galaxy, just a dim scratch,’ and if we ever do make a starship detection, this could be more or less what we find, a changeable, ambiguous object.

Image: Note the bow shock in the binary star system BZ Cam, created as the system moves through surrounding interstellar gas. In most cataclysmic variables, matter from a normal star accumulates on the surface of the companion white dwarf star, eventually causing a nova-like flare. In BZ Cam, however, light appears to flicker unpredictably, and an unusually large wind of particles is being expelled. BZ Cam lies about 2500 light-years away toward the constellation of Camelopardalis. Credit: R. Casalegno, C. Conselice et al., WIYN, NOAO, MURST, NSF.

Magsail Braking and Detection

A magnetic sail (‘magsail’) that deflects charged particles is also an interesting possibility. In his 1995 paper, Zubrin points out that a sail like this would be of value because it could decelerate a starship without the use of propellant, allowing it to brake against the stellar wind of the destination star. Here again we get a bow shock which will heat the interstellar medium to a degree dependent on the ship’s velocity, creating a plasma that will encounter the magnetic field of the magsail and produce radiation. This is an ingenious analysis — Zubrin, having gone through the equations governing the rate of deceleration of a magsail in the interstellar medium, notes the changes that occur as the velocity of the ship decreases and the bow shock heating begins to fall, causing the cyclotron radiation emitted by the bow shock to fall at the same time.

A large enough starship decelerating as it neared its destination should, according to Zubrin, put out emissions in the X-ray and radio ranges. Thus we get our starship signature: “The decline in bremsstrahlung energies and cyclotron frequencies in time in accord with the form of equation (2) [governing the rate of deceleration of the magsail] would be a dead giveaway that the emitting object was a decelerating magsail.” Governing the radiation emitted is the ship’s velocity and the density of ions in the interstellar medium. Zubrin calculates that at a density of 1 ion per cubic centimeter, a ship decelerating from a cruise velocity of 0.1 c will produce radiation at about 12 kHz.

Would we have a real chance at such a detection? From the paper:

It can be seen that the magsail radiation of a characteristic fusion starship being decelerated from a cruise velocity of 0.1c could be detected by a 6 km orbiting antenna from a distance of 400 light years, while that emitted by a characteristic antimatter photon rocket in its deceleration phase could be seen as far away as 2,000 light-years. There are about 100,000,000 stellar systems to be found within the latter distance. This extended range detection capability combined with magsail radiation’s unique time-dependent frequency spectrum appears to make a search for magsail radiation the most promising option for extraterrestrial starship detection.

You’ll recall that Zubrin estimated the characteristic mass of his ‘standard’ starship as 1,000,000 tons, something he describes as ‘a speculative guess.’ But even if the guess is off the mark, the idea of starship detection remains sound, in his view, because a decrease of ship mass by two orders of magnitude only decreases the detectability distance by one order of magnitude. We’re still looking at detecting a 10,000 ton starship (using a magsail) at 40 light years via a 6 km antenna, while a 30 km antenna could make the detection at a range of 200 light years.

Further thoughts on starship detection tomorrow. But let me add one note before closing: Al Jackson pointed out in the comments to yesterday’s post that Zubrin does not reference an important paper. It’s D. R. J. Viewing, C. Horswell, E. W. Palmer, “Detection of Starships,” JBIS, 30, 99-104 (1977), and it’s not one I’ve seen yet either. Because of that, let me quote Al:

The Viewing , et.al., paper looks at two kinds of starships, Innocuous and Energetic. Almost the same propulsion systems are considered as in Zubrin’s paper. That paper got me interested in what truly relativistic ships would look like in the simple case when a propulsion system does is not 100% efficient, and loses energy by waste heat. Suppose that in its rest frame it radiates isotropically. A simple relativistic kinematic effect will be that the radiation will be beamed relative to another rest frame. Called the ‘head light’ effect in special relativity. See: Correspondence: A. A. Jackson, IV, “Ultra-Relativistic Starships,” JBIS, 32, 240 (1979).

The Zubrin reference is “Detection of Extraterrestrial Civilizations via the Spectral Signature of Advanced Interstellar Spacecraft,” Progress in the Search for Extraterrestrial Life, ASP Conference Series Vol. 74 (1995). Available online.

To Detect a Starship

Several Centauri Dreams readers passed along Seth Shostak’s latest article on SETI in IEEE Spectrum, a piece that invokes the ‘Wow!’ signal at Ohio State and goes on to make the case for continuing the hunt. Shostak thinks both the ongoing search for exoplanets and refinements in our signal detection technology, including optical SETI, should keep us active. “No, we haven’t found any signals so far, but there’s a growing incentive provided by new findings in astronomy and biology, and the instruments are getting better,” he writes. “Thirty-five years from now, we may really find a signal that will make us say ‘Wow!’”

The IEEE Spectrum piece doesn’t break any new ground, but it’s another example of the ‘Wow!’ signal getting broader coverage, and I now find that people routinely bring the Ohio State event up when I talk to audiences about SETI. Meanwhile, let’s think about some truly exotic possibilities when it comes to detecting extraterrestrial life. Would it be possible, for example, to detect signs of an alien civilization not just by a beacon, but by a spacecraft in transit between the stars? I was intrigued to learn that Robert Zubrin, of Mars Society fame, has investigated the question in a 1995 paper.

Modeling an Interstellar Craft

Zubrin has interstellar credentials, of course, most notably in his work with Dana Andrews on the Bussard ramjet and the question of drag, which has fed into studies of magsails and their uses. I also highly recommend his book Entering Space: Creating a Spacefaring Civilization (Tarcher, 1999) for its overview of interstellar concepts, a helpful source for those new to the interstellar field. In the 1995 paper on spacecraft detection, he makes an interesting point. One of the things that muddies the SETI investigation is our lack of knowledge of how aliens think, so that we are left to guess at what a species might do if trying to communicate. By searching for the spectral signal of an interstellar transportation system, we can abandon that concern:

The advantage of our approach is that the characteristic power levels associated with interstellar transportation systems are many orders of magnitude greater than those required for communication, and so the signal strength may be much greater. Furthermore, unlike communication which is governed by a fairly arbitrary selection of technology and mutually agreed upon conventions, transportation systems are governed much more stringently by the laws of physics. No understanding of alien psychology is necessary to detect a starship.

But what kind of starships are we looking for? For the purposes of analysis, Zubrin has to rule out breakthroughs in physics that an extraterrestrial culture may have made but we have not — we have no way to characterize a ship propelled by something exotic like zero-point energy. But antimatter, fusion and fission rockets, as well as magnetic sails, come within his province. If the alien starship works within the limits of physics as we know them, then a speed of about 10 percent of lightspeed seems minimal — Zubrin selects this figure under the assumption of human-like life-spans so that the mission can be completed within a working lifetime. He also assumes that technological creatures are social and need a large crew for a long voyage.

Image: Could we detect an interstellar spacecraft more readily than an accidental signal or even a beacon from an extraterrestrial civilization? Credit: Adrian Mann.

We’re left with an optimum starship of considerable mass, especially when we throw in shielding against cosmic rays and near relativistic interstellar particles. Let’s assume 1,000,000 tons, with an exhaust velocity of 0.1c, with average accelerations on the order of 0.1 m/s2. Zubrin works out a power requirement for his ‘standard’ starship of 1500 TW, which equals 0.9 percent of all the sunlight falling on the Earth, a figure only 11 orders of magnitude less than the total output of the Sun. By comparison, a Saturn V’s S1 stage had a power output of 0.1 TW. 1500 TW sounds extreme (Zubrin cites a collective human use of about 12 TW today) but if you keep power production growing at a rate of 2.6% per year, the rate current when the paper was written, then we hit 1500 TW around the year 2180 and get to 30,000 TW in 2300:

…the maximum size of individual power plants has been growing at a rate of 2 orders of magnitude per century for the past two hundred years. Thus if present trends continue, the apparently astronomical power required of our standard starship should be common in 3 or 4 centuries, a blink of an eye on the cosmic time scale.

Signature of a Starship

Zubrin is interested in the spectral signature of the standard starship, which should be different from an astrophysical object because its position and speed should change over time. The hope would be that future space telescopes or even terrestrial instruments could detect an object like this in many wavebands. The problem becomes one of collecting enough photons on a detector. High-power antimatter drives should emit huge amounts of gamma rays, but at interstellar distances we get a rate of impacts per square meter of collection area that is quite small. The standard starship may evade detection.

Consider: Zubrin calculates that a starship putting out 10,000 TW of 200 MeV gamma radiation at a distance of one light year from Earth would cause just 7.5 photons per year to strike a 1 square meter collection device. Such a spacecraft would be undetectable. The same problem occurs with X-ray emissions produced as bremsstrahlung radiation from a fusion engine (assuming D/He3), and while a detection within one light year is remotely possible, at 10 light years the impact rate falls to two per hour and the signal fades into the background noise. It’s in the realm of visible light that things begin to get more interesting. Visible light radiation from the ship’s exhaust becomes detectable through a telescope for many light years.

Thus our best case: An antimatter photon rocket with a jet power of 120,000 TW using a reflective nozzle to focus emitted light to a half angle of 30 degrees should produce an exhaust stream we can detect:

Such an object at a distance of 1 light year would be seen from Earth as a 17th magnitude light source, and could be detected on film by a first class amateur telescope. The 200 inch telescope on Mount Palomar could image it at 20 light-years, and the Hubble Space Telescope at a distance of about 300 light-years… Since at least for the upper-end telescopes considered, the number of stellar systems within range is significant (100,000 stars are within 200 light-years of Earth) this approach offers some hope for a successful search. The light from the photon rocket could be distinguished from that of a dim star by the lack of hydrogen lines in the rocket’s emissions.

More on this tomorrow, when we’ll look at magsail detection and the possibilities for other kinds of sails as well as worldships. The paper is Zubrin, “Detection of Extraterrestrial Civilizations via the Spectral Signature of Advanced Interstellar Spacecraft,” Progress in the Search for Extraterrestrial Life, ASP Conference Series Vol. 74 (1995). Available online.