Centauri Dreams: Creative Constraints and Starflight
I discovered Karl Schroeder’s work when I was researching brown dwarfs some years ago. Who knew that somebody was writing novels about civilizations around these dim objects? Permanence (Tor, 2003) was a real eye-opener, as were the deep-space cultures it described. Schroeder hooked me again with his latest book — he’s dealing with a preoccupation of mine, a human presence in the deep space regions between ourselves and the nearest stars, where resources are abundant and dark worlds move far from any sun. How to maintain such a society and allow it to grow into something like an empire? Karl explains the mechanism below. Science fiction fans, of which there are many on Centauri Dreams, will know Karl as the author of many other novels, including Ventus (2000), Lady of Mazes (2005) and Sun of Suns (2006).
by Karl Schroeder
My newest science fiction novel, Lockstep, has just finished its serialization in Analogmagazine, and Tor Books will have it on the bookshelves March 24. Reactions have been pretty favourable—except that I’ve managed to offend a small but vocal group of my readers. It seems that some people are outraged that I’ve written an SF story in which faster than light travel is impossible.
I did write Lockstep because I understood that it’s not actual starflight that interests most people—it’s the romance of a Star Trek or Star Wars-type interstellar civilization they want. Not the reality, but the fantasy. Even so, I misjudged the, well, the fervor with which some people cling to the belief that the lightspeed limit will just somehow, magically and handwavingly, get engineered around.
This is ironic, because the whole point of Lockstep was to find a way to have that Star Wars-like interstellar civilization in reality and not just fantasy. As an artist, I’m familiar with the power of creative constraint to generate ideas, and for Lockstep I put two constraints on myself: 1) No FTL or unknown science would be allowed in the novel. 2) The novel would contain a full-blown interstellar civilization exactly like those you find in books with FTL.
Creativity under constraint is the best kind of creativity; it’s the kind that really may take us to the stars someday. In this case, by placing such mutually contradictory — even impossible — restrictions on myself, I was forced into a solution that, in hindsight, is obvious. It is simply this: everyone I know of who has thought about interstellar civilization has thought that the big problem to be solved is the problem of speed. The issue, though (as opposed to the problem), is how to travel to an interstellar destination, spend some time there, and return to the same home you left. Near-c travel solves this problem for you, but not for those you left at home. FTL solves the problem for both you and home, but with the caveat that it’s impossible. (Okay, okay, for the outraged among you: as far as we know. To put it more exactly, we can’t prove that FTL is impossible any more than we can prove that Santa Claus doesn’t exist. I’ll concede that.)
Read the rest here…
Of Orphan Worlds and Interstellar Island Hopping
From Centauri Dreams:
Because of my fascination with exotic venues for astrobiology, I’ve always enjoyed Karl Schroeder’s novels. The Canadian writer explored brown dwarf planets as future venues for human settlement in Permanence (2002), and in his new book Lockstep (soon to be published by Tor, currently being serialized in Analog), Schroeder looks at ‘rogue’ planets, worlds that move through the galaxy without a central star. Imagine crimson worlds baked by cosmic radiation, their surfaces building up, over the aeons, the rust red complex organic molecules called tholins. Or consider gas giants long ago ejected from the system that gave them birth by close encounters with other worlds.
Objects like these and more are surely out there given what we know about gravitational interactions within planetary systems, and they’re probably out there in huge numbers. I’m not going to review how Lockstep uses them just yet — in any case, I haven’t finished the book — but we’ll return to its ingenious solution to time and distance problems in a future post. Right now I just want to mention that one of Schroeder’s characters muses upon ‘a hundred thousand nomad planets for every star in the galaxy.’ Now that’s some serious real estate.
If the number sounds like a novelistic exaggeration, it’s nonetheless drawn from recent work. Schroeder is invoking the work of Louis Strigari (Stanford University), who has studied the possibilities not only of planets ejected from their own systems but those that may form directly from a molecular cloud. The figure of 105 free-floating planetary objects for every main sequence star is from a 2012 paper in Monthly Notices of the Royal Astronomical Society (you can read more about Strigari’s ideas in ‘Island-Hopping’ to the Stars).
Rogue planets would be tricky to find but gravitational microlensing should help us set constraints on their actual numbers, and as we’ll see below, direct imaging has its uses. If rogue worlds are available in such quantities, we can imagine a starfaring culture capable of exploiting their resources. We can even speculate that a thick atmosphere that can trap infrared heat coupled with tectonic or radioactive heat sources from within could sustain elemental forms of life even in the absence of a star. Tens of thousands of objects in nearby interstellar space would obviously be a spur for exploration.
A Newly Found Orphan World
Eighty light years from Earth floats a solitary planet that has been discovered through its heat signature in data collected by the Pan-STARRS 1 wide-field survey telescope on Maui. In mass, color, and energy output, the world is similar to directly imaged planets. As you might expect, PSO J318.5-22, a gas giant about six times the mass of Jupiter, turned up during a search for brown dwarfs, delving into the datasets of a survey that has already produced about 4000 terabytes of information. The discovery was then followed up through multiple observations by equipment on nearby Mauna Kea, with spectra from the NASA Infrared Telescope Facility and the Gemini North Telescope indicating the young, low-mass object was not a brown dwarf.
Image: Multicolor image from the Pan-STARRS1 telescope of the free-floating planet PSO J318.5-22, in the constellation of Capricornus. The planet is extremely cold and faint, about 100 billion times fainter in optical light than the planet Venus. Most of its energy is emitted at infrared wavelengths. The image is 125 arcseconds on a side. Credit: N. Metcalfe & Pan-STARRS 1 Science Consortium.
“We have never before seen an object free-floating in space that that looks like this. It has all the characteristics of young planets found around other stars, but it is drifting out there all alone,” explained team leader Dr. Michael Liu of the Institute for Astronomy at the University of Hawaii at Manoa. “I had often wondered if such solitary objects exist, and now we know they do.”
The find is interesting on a number of levels, not least of which is that observations of gas giant planets around young stars have shown that their spectra differ from those of L- and T-class brown dwarfs. Young planets like these, according to the paper on this work, show redder colors in the near-infrared, fainter absolute magnitudes at the same wavelength and other spectral peculiarities that suggest the line of development between brown dwarfs and gas giant planets may not be as clear cut as once assumed. The paper makes clear how complex the issue is:
PSO J318.5−22 shares a strong physical similarity to the young dusty planets HR 8799bcd and 2MASS J1207−39b, as seen in its colors, absolute magnitudes, spectrum, luminosity, and mass. Most notably, it is the first field L dwarf with near-IR absolute magnitudes as faint as the HR 8799 and 2MASS J1207−39 planets, demonstrating that the very red, faint region of the near-IR color-magnitude diagram is not exclusive to young exoplanets. Its probable membership in the β Pic moving group makes it a new substellar benchmark at young ages and planetary masses.
A landmark indeed, and here the Beta Pictoris moving group, a collection of young stars formed about twelve million years ago, is worth noting. Beta Pictoris itself is known to have a young gas giant planet in orbit around it. The newly detected PSO J318.5−22 is lower still in mass than the Beta Pictoris planet and it is thought to have formed in a different way. The paper goes on:
We find very red, low-gravity L dwarfs have ≈400 K cooler temperatures relative to field objects of comparable spectral type, yet have similar luminosities. Comparing very red L dwarf spectra to each other and to directly imaged planets highlights the challenges of diagnosing physical properties from near-IR spectra.
The beauty of objects like these from an astronomical point of view is that we don’t have to worry about filtering out the overwhelming light of a parent star as we study them. Co-author Niall Deacon (Max Planck Institute for Astronomy) thinks PSO J318.5−22 will “provide a wonderful view into the inner workings of gas-giant planets like Jupiter shortly after their birth.” The discovery also gives us much to think about in terms of future explorations as we contemplate a cosmos in which perhaps vast numbers of planets move in solitary trajectories through the galaxy.
I like the idea of targeting “rogue” planets as potential interstellar missions within the next 100 years. The probes can be smaller and the fuel problem won’t be as bad.
Karl Schroeder isn’t the only author who has used rogue planets as interstellar destinations. The old Space: 1999 television series addressed it as well as Peter Watts Blindsight. Good stuff.
Skylab II
From Space.com:
NASA’s first manned outpost in deep space may be a repurposed rocket part, just like the agency’s first-ever astronaut abode in Earth orbit.
With a little tinkering, the upper-stage hydrogen propellant tank of NASA’s huge Space Launch System rocket would make a nice and relatively cheap deep-space habitat, some researchers say. They call the proposed craft “Skylab II,” an homage to the 1970s Skylab space station that was a modified third stage of a Saturn V moon rocket.
“This idea is not challenging technology
,” said Brand Griffin, an engineer with Gray Research, Inc., who works with the Advanced Concepts Office at NASA’s Marshall Space Flight Center in Huntsville, Ala.
“It’s just trying to say, ‘Is this the time to be able to look at existing assets, planned assets and incorporate those into what we have as a destination of getting humans beyond LEO [low-Earth orbit]?'” Griffin said Wednesday (March 27) during a presentation with NASA’s Future In-Space Operations working group.
A roomy home in deep space
NASA is developing the Space Launch System (SLS) to launch astronauts toward distant destinations such as near-Earth asteroids and Mars. The rocket’s first test flight is slated for 2017, and NASA wants it to start lofting crews by 2021.
The SLS will stand 384 feet tall (117 meters) in its biggest (“evolved”) incarnation, which will be capable of blasting 130 metric tons of payload
The tank’s dimensions yield an internal volume of 17,481 cubic feet (495 cubic m) — roughly equivalent to a two-story house. That’s much roomier than a potential deep-space habitat derived from modules of the International Space Station (ISS), which are just 14.8 feet (4.5 m) wide, Griffin said.
The tank-based Skylab II could accommodate a crew of four comfortably and carry enough gear and food to last for several years at a time without requiring a resupply, he added. Further, it would launch aboard the SLS in a single piece, whereas ISS-derived habitats would need to link up multiple components in space.
Because of this, Skylab II would require relatively few launches to establish and maintain, Griffin said. That and the use of existing SLS-manufacturing infrastructure would translate into big cost savings — a key selling point in today’s tough fiscal climate.
“We will have the facilities in place, the tooling, the personnel, all the supply chain and everything else,” Griffin said.
He compared the overall concept with the original Skylab space station, which was built in a time of declining NASA budgets after the boom years of the Apollo program.
Skylab “was a project embedded under the Apollo program,” Griffin said. “In many ways, this could follow that same pattern. It could be a project embedded under SLS and be able to, ideally, not incur some of the costs of program startup.”
There has been much caterwauling in the space advocacy community about the Space Launch System ( ne, “The Senate Launch System” ) concerning its cost and lack of purpose and/or destinations.
Of course, the thing was designed by Congress in order to fund a jobs program in the NASA Centers for the good voters of those districts. But it’s a seriously underfunded program, with just enough money to keep the civil servants of NASA employed, with just enough contractor support to keep them happy.
In the meantime, ideas like Skylab II, the Spacehab at EML-2 and the asteroid capture scheme rear their ugly heads and claim they’re economical in these austeric times.
My money is still on Elon Musk, Bob Bigelow, Dennis Tito and company.
Advanced Oort Cloud Civilisations?
From Centauri Dreams:
Jules Verne once had the notion of a comet grazing the Earth and carrying off a number of astounded people, whose adventures comprise the plot of the 1877 novel Off on a Comet. It’s a great yarn that was chosen by Hugo Gernsback to be reprinted as a serial in the first issues of his new magazine Amazing Stories back in 1926, but with a diameter of 2300 kilometers, Verne’s comet was much larger than anything we’ve actually observed. Comets tend to be small but they make up for it in volume, with an estimated 100 billion to several trillion thought to exist in the Oort Cloud. All that adds up to a total mass of several times the Earth’s.
Of course, coming up with mass estimates is, as with so much else about the Oort Cloud, a tricky business. Paul R. Weissman noted a probable error of about one order of magnitude when he produced the above estimate in 1983. What we are safe in saying is something that has caught Freeman Dyson’s attention: While most of the mass and volume in the galaxy is comprised of stars and planets, most of the area actually belongs to asteroids and comets. There’s a lot of real estate out there, and we’ll want to take advantage of it as we move into the outer Solar System and beyond.
Comets and Resources
Embedded with rock, dust and organic molecules, comets are composed of water ice as well as frozen gases like methane, carbon dioxide, carbon monoxide, ammonia and an assortment of compounds containing nitrogen, oxygen and sulfur. Porous and undifferentiated, these bodies are malleable enough to make them interesting from the standpoint of resource extraction. Richard P. Terra wrote about the possibilities in a 1991 article published in Analog:
This light fragile structure means that the resources present in the comet nuclei will be readily accessible to any human settlers. The porous mixture of dust and ice would offer little mechanical resistance, and the two components could easily be separated by the application of heat. Volatiles could be further refined through fractional distillation while the dust, which has a high content of iron and other ferrous metals, could easily be manipulated with magnetic fields.
Put a human infrastructure out in the realm of the comets, in other words, and resource extraction should be a workable proposition. Terra talks about colonies operating in the Oort Cloud but we can also consider it, as he does, a proving ground for even deeper space technologies aimed at crossing the gulf between the stars. Either way, as permanent settlements or as way stations offering resources on millennial journeys, comets should be plentiful given that the Oort Cloud may extend half the distance to Alpha Centauri. Terra goes on:
Little additional crushing or other mechanical processing of the dust would be necessary, and its fine, loose-grained structure would make it ideal for subsequent chemical processing and refining. Comet nuclei thus represent a vast reservoir of easily accessible materials: water, carbon dioxide, ammonia, methane, and a variety of metals and complex organics.
Energy by Starlight
Given that comets probably formed on the outer edges of the solar nebula, their early orbits would have been more or less in the same plane as the rest of the young system, but gravitational interactions with passing stars would have randomized their orbital inclinations, eventually producing a sphere of the kind Jan Oort first postulated back in 1950. Much of this is speculative, because we have little observational evidence to go on, but the major part of the cometary shell probably extends from 40,000 to 60,000 AU, while a projected inner Oort population extending from just beyond the Kuiper Belt out to 10,000 AU may have cometary orbits more or less in the plane of the ecliptic. Out past 10,000 AU the separation between comets is wide, perhaps about 20 AU, meaning that any communities that form out here will be incredibly isolated.
Image: An artist’s rendering of the Kuiper Belt and Oort Cloud. Credit: NASA/Donald K. Yeomans.
Whether humans can exploit cometary resources this far from home will depend on whether or not they can find sources of energy. In a paper called “Fastships and Nomads,” presented at the Conference on Interstellar Migration held at Los Alamos in 1983, Eric Jones and Ben Finney give a nod to non-renewable energy sources like deuterium, given that heavy elements like uranium will be hard to come by. Indeed, a typical comet, in Richard Terra’s figures, holds between 50,000 and 100,000 metric tons of deuterium, enough to power early settlement and mining.
But over the long haul, Jones and Finney are interested in keeping colonies alive through renewable resources, and that means starlight. The researchers talk about building vast mirrors using aluminum from comets, with each 1 MW mirror about the size of the continental United States. Now here’s a science fiction setting with punch, as the two describe it:
Although the mirrors would be tended by autonomous maintenance robots, the nomads would have to live nearby in case something went wrong… Although we could imagine that the several hundred people who could be supported by the resources of a single comet might live in a single habitat, the mirrors supporting that community would be spread across about 150,000 km. Trouble with a mirror or robot on the periphery of the mirror array would mean a long trip, several hours at least. It would make more sense if the community were dispersed in smaller groups so that trouble could be reached in a shorter time. There are also social reasons for expecting the nomad communities to be divided into smaller co-living groups.
Jones and Finney go on to point out that humans tend to work best in groups of about a dozen adults, whether in the form of hunter/gatherer bands, army platoons, bridge clubs or political cells. This observation of behavior leads them to speculate that bands of about 25 men, women and children would live together in a large habitat — think again of an O’Neill cylinder — built out of cometary materials, from which they would tend a mirror farm with the help of robots and computers. Each small group would tend a mirror farm perhaps 30,000 kilometers across.
The picture widens beyond this to include the need for larger communities that would occasionally come together, helping to avoid the genetic dangers of inbreeding and providing a larger social environment. Thus we might have about 500 individuals in clusters of 20 cometary bands which would stay in contact and periodically meet. Jones and Finney consider the band-tribe structure to be the smallest grouping that seems practical for any human community. Who would such a community attract — outcasts, dissidents, adventurers? And how would Oort Cloud settlers react to the possibility of going further still, to another star?
While by no means is this is a new theory, ( note the Jules Verne story ), it presents the scenario of the very slow spreading of intelligent biological life through-out the Galaxy ( see Slow Galactic Colonization, Zoo Hypothesis and the Fermi Paradox ).
Now here’s a thought; could a potential alien Oort Cloud civilization be the basis of the Ancient Astronaut Theory and the legends of the Sumerian Gods, the Anunnaki?
There’s no hard evidence of that of course, but there are Pluto-sized and larger objects in the Kuiper Belt glowing in the infrared, a sign that was said to represent a Dyson Sphere type civilisation.
Either these are natural objects such as Brown Dwarf stars, or potential alien civilisations whom don’t care whether they are detected in the infrared or not.
And that’s disturbing.
Did Voyager 1 Leave The Solar System?
From nytimes.com:
For about three hours on Wednesday, Voyager 1 had left the solar system — before a rewritten news release headline pulled it back in. Voyager 1, one of two spacecraft NASA launched in 1977 on a grand tour of the outer planets, is now nearly 11.5 billion miles from the Sun, speeding away at 38,000 miles per hour. In a paper accepted by the journal Geophysical Review Letters, William R. Webber of New Mexico State University and Frank B. McDonald of the University of Maryland reported that on Aug. 25 last year, the spacecraft observed a sudden change in the mix of cosmic rays hitting it.
Cosmic rays are high-speed charged particles, mostly protons. Voyager 1’s instruments recorded nearly a doubling of cosmic rays from outside the solar system, while the intensity of cosmic rays that had been trapped in the outer solar system dropped by 90 percent.
The American Geophysical Union, publisher of the journal, sent out the news Wednesday morning: “Voyager 1 has left the solar system.” NASA officials, surprised, countered with a contrary statement from Edward C. Stone, the Voyager project scientist. “It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space,” Dr. Stone said. He said that the critical indicator would be a change in the direction of the magnetic field, not cosmic rays, for marking the outermost boundary of the solar system. In their paper, Dr. Webber and Dr. McDonald (who died only six days after Voyager observed the shift in cosmic rays) did not claim that Voyager 1 was in interstellar space, but had entered a part of the solar system they called the “heliocliff.” The geophysical union then sent out another e-mail with the same article but a milder headline: “Voyager 1 has entered a new region of space.”
Eventually Voyager 1 will leave the Solar System and there will be no dispute about it.
In the meantime, mainstream science will learn and post about the outer edges of the Solar System as Voyager 1 creeps along at .00002 lightspeed ( 37,500 mph ) .
Of course there are those in mainstream media and science who believe that mankind will never leave the Solar System because they proclaim that spacecraft will never be built that go faster than that.
Already the Pluto probe New Horizon traveling at 54,500 mph is breaking Voyager’s speed record and will probably leave the Solar System before Voyager does!
I’m certain in 100 years star probes will be launched toward Alpha Centauri and Tau Ceti that reach appreciable percentages of lightspeed bypassing all of our old interplanetary probes and perhaps in several centuries, mankind’s interstellar colonies will be picking up these old probes to study them, like old time capsules!
Where’s Voyager 1? That Depends.
Hat tip to the Daily Grail.
The Covert Mainstream
From mysteriousuniverse.org:
The late researcher of UFOs, Dr. J. Allen Hynek, once wrote that, “In one’s frustration it is all too easy to seize on an explanation of the “Men from Mars” variety and to ignore the many UFO features unaccounted for… We may be inadvertently and artificially increasing the significance of the conspicuous features while the part we ignore–or that which is not reported by the untrained witness–may contain the clue to the whole subject.”
I would also argue just as well that, in addition to part of the UFO enigma that remain hidden, there might be researchers in this field that do the same.
I recently attended the 2013 International UFO Congress as a speaker, as well as a panelist for a discussion with fellow researchers Stanton Friedman and Richard Dolan, where we discussed the state of ufology in the 21st century. The Congress, arguably the largest and most well-attended UFO conference anywhere in the world, is not only a proving ground for both the budding young researcher and the decades-in ufologist alike; it is also a breeding ground for new ideas and the formation of new hypotheses, which may eventually sow the seeds of new insight toward solving this enduring mystery.
International UFO Congress – Educating the World One Person at a Time
And yet, while there is this obvious mainstream component to the UFO research community, there is another more clandestine arm of the community that is less active before the public eye… but not all things that are “secretive” are necessarily nefarious or part of some grand dark conspiracy. In truth, it may be within the humble confines of Ufology’s “Shadow Research Community” that some of the more innovative thinkers exist, working out problems behind the scenes that many point-and-click researchers of today might overlook altogether.
No doubt, a statement of this caliber might be enough to anger many prideful UFO researchers at large (although I would argue that most serious UFO researchers will learn early on to rid themselves of any pride, lest they be crushed by the seething sensationalism in the mainstream media, and their overt approach toward the UFO community in general). But again, the notion of their being an underlying academic element that persists behind the mainstream study of UFOs–if one could ever call UFO research “mainstream” at all–is nothing new.
French Ufologist and computer scientist Jacques Vallee in his book Alien Contact by Human Deception argued that there were many private UFO researchers in academic circles–perhaps a few hundred he knew and had worked with–that studied the UFO problem intently, but without doing so publicly. Vallee referred to this as being a sort of “Invisible College” that has continued serious scientific study of UFOs, despite the fact that since the late 1960s, Edward Condon and his University of Colorado UFO Project helped determine that once and for all, the UFO mystery would forever be pseudoscientific.
Hynek and Vallee
Indeed, the general study of UFOs has largely been pseudoscientific, in that the largest body of serious research spanning the last several decades has been carried out by civilians, and often those with little or no academic or technical training suited for study of the phenomenon. While this has often been a point of criticism by scientists the likes of Carl Sagan, Stephen Hawking, and many others, it also highlights yet another problem in the UFO field: the tendency for academics to push for debunking of UFO phenomenon or labeling it as pseudoscientific, while doing very little on their own accord to help further the serious scientific study of the phenomenon aside from waging an ongoing war of words.
Angela Joiner
To the credit of the academicians, it should be noted that to openly and publicly embrace the study of UFOs most often becomes equivalent to academic suicide in the Western world. There are many instances where professionals have been forced to choose between studying fringe subjects and maintaing a career by more conventional standards. Scientists such as Dean Radin, who lost his teaching position for openly discussing parapsychology, comes to mind, as well as members of the media like Angelia Joiner, who famously reported on the Stephenville, Texas UFO flap several years ago; the latter was eventually pinned into a position where she felt she had to resign as a reporter for the Stephenville Empire-Tribune, in order to be able to continue following the UFO story.
Altogether, the problem here is that UFO research, by virtue of the fringe or “kooky” subject matter it has often become directly associated with, warrants blacklisting among professionals (especially scientists, university professors, etc). In my own experience, I’ve had numerous interactions with those in academia who reach out to me, often under aliases at first, to express interest not just in UFO research, but to share their own ideas and findings (albeit covertly) from an academic standpoint. The reasons these individuals would reach out to ufologists at all most often has to do, in my experience, with a hope for finding someone who will allow them to plead their case, but also that they might be able to influence or steer with their own professional observations. On both counts, this is usually a good thing, as it allows the academics to find others who won’t be so openly critical with the treatment of fringy subject matter, but the less technically skilled civilian researcher also gains insight from members of the scientific community.
Thus, while there is certainly a “trickle down effect” with regard to academics who occasionally reveal tidbits of insight to the publicly known UFO researchers, it could be argued that some of the most plausible and interesting insights into the field of ufology may exist behind the scenes, in what Vallee dubbed a so-called “Invisible College.” Today, could we ever get a serious, ongoing academic discourse on UFOs back into mainstream scientific circles… or is this even something that could ever be afforded the modern UFO research community, with an ever-growing divide that is occurring between the “believer” and “skeptic” diametric?
I actually don’t find it odd that there are some “mainstream” scientists working on the UFO mystery on their own time. After all that is what Jacques Vallee and Stanton Freidman did before devoting their studies of UFOs full-time .
The late J. Allen Hynek was a little different, he waited until he had a government pension before becoming a convert to studying UFOs on a full-time scientific basis.
Believe it or not, it is this “covert mainstream” that is fueling SETI, astroarcheology, astrobiological and advanced propulsion technology research.
Or perhaps, it’s the “science-fiction” collective consciousness?
Behind The Scenes: Ufology’s Shadow Research Community
Hat tip to the Daily Grail.
Worldships and Planetary Chauvanism
From Centauri Dreams:
The assumptions we bring to interstellar flight shape the futures we can imagine. It’s useful, then, to question those assumptions at every turn, particularly the one that says the reason we will go to the stars is to find other planets like the Earth. The thought is natural enough, and it’s built into the exoplanet enterprise, for the one thing we get excited about more than any other is the prospect of finding small, rocky worlds at about Earth’s distance from a Sun-like star. This is what Kepler is all about. From an astrobiological perspective, this focus makes sense, as we want to know whether there is other life — particularly intelligent life — in the universe.
But interstellar expansion may not involve terrestrial-class worlds at all, though they would still remain the subject of intense study. Let’s assume for a moment that a future human civilization expands to the stars in worldships that take hundreds or even thousands of years to reach their destination. The occupants of these enormous vessels might travel in a tightly packed urban environment or perhaps in a much more ‘rural’ setting with Earth-like amenities. Many of them would live out their lives in transit, without the ability to be there at journey’s end. We can only speculate what kind of social structures might emerge around the ultimate mission imperative.
Moving Beyond a Planetary Surface
Humans who have grown up in a place that has effectively become their world are going to find its norms prevail, and the idea of living on a planetary surface may hold little interest. Isaac Asimov once wrote about what he called ‘planetary chauvinism,’ which falls back on something Eric M. Jones wrote back in the 1980s. Jones believed that people traveling to another star will be far more intent on mining asteroids and the moons of planets to help them build new habitats for their own expanding population. Stephen Ashworth, a familiar figure on Centauri Dreams, writes about what he calls ‘astro-civilizations,’ space-based cultures that focus on the material and energy resources of whatever system they are in rather than planets.
Ashworth’s twin essays appear in a 2012 issue of the Journal of the British Interplanetary Society (citation below) that grew out of a worldship symposium held in 2011 at BIS headquarters in London. The entire issue is a wonderful contribution to the growing body of research on worldships and their uses. Ashworth points out that a planetary civilization like our own thinks in terms of planetary resources and, when looking toward interstellar options, naturally assumes the primary goal will be to locate new ‘Earths.’ A corollary is the assumption of rapid transport that mirrors the kind of missions used to explore our own Solar System.
Image: A worldship kilometers in length as envisioned by space artist Adrian Mann.
An astro-civilization is built on different premises, and evolves naturally enough from the space efforts of its forebears. Let me quote Ashworth on this:
“A space-based or astro-civilisation…is based on technologies which are an extension of those required on planetary surfaces, most importantly the design of structures which provide artificial gravity by rotation, and the ability to mine and process raw materials in microgravity conditions. In fact a hierarchical progression of technology development can be traced, in which each new departure depends upon all the previous ones, which leads ultimately to an astro-civilisation.
The technology development Ashworth is talking about is a natural extension of planetary methods, moving through agriculture and industrialization into a focus on the recovery of materials that have not been concentrated on a planetary surface, and on human adaptation not only to lower levels of gravity but to life in pressurized structures beginning with outposts on the Moon, Mars and out into the system. Assume sufficient expertise with microgravity environments — and this will come in due course — and the human reliance upon 1 g, and for that matter upon planetary surfaces, begins to diminish. Power sources move away from fossil fuels and gravitate toward nuclear and solar power sources usable anywhere in the galaxy.
Agriculture likewise moves from industrialized methods on planetary surfaces to hydroponic agriculture in artificial environments. Ashworth sees this as a progression taking our adaptable species from the African Savannah to the land surface of the entire Earth and on to the planets, from which we begin, as we master the wide range of new habitats becoming available, to adapt to living in space itself. He sees a continuation in the increase of population densities that took us from nomadic life to villages to cities, finally being extended into a fully urbanized existence that will flourish inside large space colonies and, eventually, worldships.
An interstellar worldship is, after all, a simple extension from a colony world that remains in orbit around our own star. That colony world, within which people can sustain their lives over generations, is itself an outgrowth of earlier technologies like the Space Station, where residence is temporary but within which new skills for adapting to space are gradually learned. Where I might disagree with Ashworth is on a point he himself raises, that the kind of habitats Gerard O’Neill envisioned didn’t assume high population densities at all, but rather an abundance of energy and resources that would make life far more comfortable than on a planet.
This reminds me of an old Analog article I read back in the 1970s by Larry Niven titled “Bigger Than Worlds” in which Niven gave several examples of structures that evolved into massive structures from interstellar vessels to Ringworlds and Dyson Sphere, all of which were safer than natural planets.
Of course this goes by the assumption if human goes by the “expansion” route, or the “evo devo” route proposed by Jon Smart.
Toward a Space-Based Civilization
To Ply The Martian Way
From Centauri Dreams:
Existential risks, as discussed here yesterday, seem to be all around us, from the dangers of large impactors to technologies running out of control and super-volcanoes that can cripple our civilization. We humans tend to defer thinking on large-scale risks while tightly focusing on personal risk. Even the recent events near Chelyabinsk, while highlighting the potential danger of falling objects, also produced a lot of fatalistic commentary, on the lines of ‘if it’s going to happen, there’s nothing we can do about it.’ Some media outlets did better than others with this.
Risk to individuals is understandably more vivid. When Apollo 8 left Earth orbit for the Moon in 1968, the sense of danger was palpable. After all, these astronauts were leaving an orbital regime that we were beginning to understand and were, by the hour, widening the distance between themselves and our planet. But even Apollo 8 operated within a sequenced framework of events. Through Mercury to Gemini and Apollo, we were building technologies one step at a time that all led to a common goal. No one denied the dangers faced by every crew that eventually went to the Moon, but technologies were being tested and refined as the missions continued.
Inspiration Mars is proposing something that on balance feels different. As described in yesterday’s news conference (see Millionaire plans to send couple to Mars in 2018. Is that realistic? for more), the mission would be a flyby, using a free return trajectory rather than braking into Martian orbit. The trip would last 501 days and would be undertaken by a man and a woman, probably a middle-aged married couple. Jonathan Clark, formerly of NASA and now chief medical officer for Inspiration Mars, addresses the question of risk head-on: “The real issue here is understanding the risk in an informed capacity – the crew would understand that, the team supporting them would understand that.” Multi-millionaire Dennis Tito, a one-time space tourist who heads up Inspiration Mars, says the mission will launch in 2018.
Image: A manned Mars flyby may just be doable. But is the 2018 date pushing us too hard? Image credit: NASA/JPL.
We’ll hear still more about all this when the results of a mission-feasibility study are presented next weekend at the 2013 IEEE Aerospace Conference in Montana. Given the questions raised by pushing a schedule this tightly, there will be much to consider. Do we have time to create a reliable spacecraft that can offer not only 600 cubic feet of living space but another 600 for cargo, presumably a SpaceX Dragon capsule mated to a Bigelow inflatable module? Are we ready to expose a crew to interplanetary radiation hazards without further experience with the needed shielding strategies? And what of the heat shield and its ability to protect the crew during high-speed re-entry at velocities in the range of 50,000 kilometers per hour?
For that matter, what about Falcon Heavy, the launch vehicle discussed in the feasibility analysis Inspiration Mars has produced for the conference? This is a rocket that has yet to fly.
No, this doesn’t feel much like Apollo 8. It really feels closer to the early days of aviation, when attention converged on crossing the Atlantic non-stop and pilots like Rene Fonck, Richard Byrd, Charles Nungesser and Charles Lindbergh queued up for the attempt. As with Inspiration Mars, these were privately funded attempts, in this case designed to win the Orteig Prize ($25,000), though for the pilots involved it was the accomplishment more than the paycheck that mattered. Given the problems of engine reliability at the time, it took a breakthrough technology — the Wright J-5C Whirlwind engine — to get Lindbergh and subsequent flights across.
Inspiration Mars is looking to sell media rights and sponsorships as part of the fund-raising package for the upcoming mission, which is already being heavily backed by Tito. I’m wondering if there is a breakthrough technology equivalent to the J-5C to help this mission along, because everything I read about it makes it appear suicidal. The 2018 date is forced by a favorable alignment between Mars and the Earth that will not recur until 2031, so the haste is understandable. The idea is just the kind of daring, improbable stunt that fires the imagination and forces sudden changes in perspective, and of course I wish it well. But count me a serious skeptic on the question of whether this mission will be ready to fly on the appointed date.
And if it’s not? I like the realism in the concluding remarks of the feasibility study:
A manned Mars free-return mission is a useful precursor mission to other planned Mars missions. It will develop and demonstrate many critical technologies and capabilities needed for manned Mars orbit and landing missions. The technology and other capabilities needed for this mission are needed for any future manned Mars missions. Investments in pursuing this development now would not be wasted even if this mission were to miss its launch date.
Exactly so, and there would be much development in the interim. The study goes on:
Although the next opportunity after this mission wouldn’t be for about another 13 years, any subsequent manned Mars mission would benefit from the ECLSS [Environmental Control and Life Support System], TPS [Thermal Protection System], and other preparation done for this mission. In fact, often by developing technology early lessons are learned that can reduce overall program costs. Working on this mission will also be a means to train the skilled workforce needed for the future manned Mars missions.
These are all good reasons for proceeding, leaving the 2018 date as a high-risk, long-shot option. While Inspiration Mars talks to potential partners in the aerospace industry and moves ahead with an eye on adapting near-Earth technologies for the mission, a whiff of the old space race is in the air. “If we don’t fly in 2018, the next low-hanging fruit is in ’31. We’d better have our crew trained to recognize other flags,” Tito is saying. “They’re going to be out there.”
In 1968, faced with a deadline within the decade, NASA had to make a decision on risk that was monumental — Dennis Tito reminded us at the news conference that Apollo 8 came only a year after the first test launch of the Saturn 5. Can 2018 become as tangible a deadline as 1970 was for a nation obsessed with a Moon landing before that year? If so, the technologies just might be ready, and someone is going to have to make a white-knuckle decision about the lives of two astronauts. If Inspiration Mars can get us to that point, that decision won’t come easy, but whoever makes it may want to keep the words of Seneca in mind: “It is not because things are difficult that we dare not venture. It is because we dare not venture that they are difficult.”
There are a lot of nay-sayers out yonder decrying Tito’s idea as suicidal and a waste of money. But as recently as a couple of months ago questionnaires were sent out asking for volunteers to sign up for a one way trip to Mars (Mars One), even if there’s a better than even chance of dying at any moment of it.
The results were astounding.
Tito’s idea of sending an older married couple is nothing short of public opinion genius and if successful, could be the format of any future Mars colonization efforts.
Not to mention the technologies needed for the crossing.
Habitability vs. Colonizability
From kschroeder.com:
Habitability is the measure of highest value in planet-hunting. But should it be?
Kepler and the other planet-finding missions have begun to bear fruit. We now know that most stars have planets, and that a surprising percentage will have Earth-sized worlds in their habitable zone–the region where things are not too hot and not too cold, where life can develop. Astronomers are justly fascinated by this region and what they can find there. We have the opportunity, in our lifetimes, to learn whether life exists outside our own solar system, and maybe even find out how common it is.
We have another opportunity, too–one less talked-about by astronomers but a common conversation among science fiction writers. For the first time in history, we may be able to identify worlds we could move to and live on.
As we think about this second possibility, it’s important to bear in mind that habitability and colonizability are not the same thing. Nobody seems to be doing this; I can’t find any term but habitability used to describe the exoplanets we’re finding. Whether a planet is habitable according to the current definition of the term has nothing to do with whether humans could settle there. So, the term applies to places that are vitally important for study; but it doesn’t necessarily apply to places we might want to go.
Whether a planet is habitable according to the current definition of the term has nothing to do with whether humans could settle there.To see the difference between habitability and colonizability, we can look at two very different planets: Gliese 581g and Alpha Centauri Bb. Neither of these is confirmed to exist, but we have enough data to be able to say a little about what they’re like if they do. Gliese 581g is a super-earth orbiting in the middle of its star’s habitable zone. This means liquid water could well form on its surface, which makes it a habitable world according to the current definition.
Centauri Bb, on the other hand, orbits very close to its star, and its surface temperature is likely high enough to render one half of it (it’s tidally locked to its sun, like our moon is to Earth) a magma sea. Alpha Centauri Bb is most definitely not habitable.
So Gliese 581g is habitable and Centauri Bb is not; but does this mean that 581g is more colonizable than Bb? Actually, no.
Because 581g is a super-earth, the gravity on its surface is going to be greater than Earth’s. Estimates vary, but the upper end of the range puts it at 1.7g. If you weigh 150 lbs on Earth, you’d weigh 255 lbs on 581g. This is with your current musculature; convert all your body fat to muscle and you might just be able to get around without having to use leg braces or a wheelchair. However, your cardiovascular system is going to be under a permanent strain on this world–and there’s no way to engineer your habitat to comfortably compensate.
On the other hand, Centauri Bb is about the same size as Earth. Its surface gravity is likely to be around the same. Since it’s tidally locked, half of its surface is indeed a lava hell–but the other hemisphere will be cooler, and potentially much cooler. I wouldn’t bet there’s any breathable atmosphere or open water there, but as a place to build sealed domes to live in, it’s not off the table.
Also consider that it’s easier to get stuff onto and off of the surface of Bb than the surface of a high-gravity super-earth. Add to that the very thick atmosphere that 581g is likely to have, and human subsistence on 581g–even if it’s a paradise for local life–is looking more and more awkward.
Doubtless 581g is a better candidate for life; but to me, Centauri Bb looks more colonizable.
A definition of colonizability
We’ve got a fairly good definition of what makes a planet habitable: stable temperatures suitable for the formation of liquid water. Is it possible to develop an equally satisfying (or more satisfying) definition of colonizability for a planet?
Yes–and here it is. Firstly, a colonizable world has to have an accessible surface. A super-earth with an incredibly thick atmosphere and a surface gravity of 3 or 4 gees just isn’t colonizable, however much life there may be on it.
Secondly, and more subtly, the right elements have to be accessible on the planet for it to be colonizable. This seems a bit puzzling at first, but what if Centauri Bb is the only planet in the Centauri system, and it has only trace elements of Nitrogen in its composition? It’s not going to matter how abundant everything else is. A planet like this–a star system like this–cannot support a colony of earthly life forms. Nitrogen is a critical component of biological life, at least our flavour of it.
In an article entitled “The Age of Substitutibility”, published in Science in 1978, H.E. Goeller and A.M. Weinberg proposed an artificial mineral they called Demandite. It comes in two forms. A molecule of industrial demandite would contain all the elements necessary for industrial manufacturing and construction, in the proportions that you’d get if you took, say, an average city and ground it up into a fine pulp. There’re about 20 elements in industrial demandite including carbon, iron, sodium, chlorine etc. Biological demandite, on the other hand, is made up almost entirely of just six elements: hydrogen, oxygen, carbon, nitrogen, phosphorus and sulfur. (If you ground up an entire ecosystem and looked at the proportions of these elements making it up, you could in fact find an existing molecule that has exactly the same proportions. It’s called cellulose.)
Thirdly, there must be a manageable flow of energy at the surface. The place can be hot or cold, but it has to be possible for us to move heat around. You can’t really do that at the surface of Venus, for instance; it’s 800 degrees everywhere on the ground so your air conditioning spends an insane amount of energy just overcoming this thermal inertia. Access to a gradient of temperature or energy is what makes physical work possible.
Obviously things like surface pressure, stellar intensity, distance from Earth etc. play big parts, but these are the main three factors that I can see. It should be instantly obvious that they have almost nothing to do with how far the planet is from its primary. There is no ‘colonizable zone’ similar to a ‘habitable zone’ around any given star. The judgment has to be made on a world by world basis.
Note that by this definition, Mars is marginally colonizable. Why? Not because of its temperature or low air pressure, but because it’s very low in Nitrogen, at least at the surface. The combination of Mars and Ceres may make a colonizable unit, if Ceres has a good supply of Nitrogen in its makeup–and this idea of combo environments being colonizable complicates the picture. We’re unlikely to be able to detect an object the size of Ceres around Alpha Centauri, so long-distance elimination of a system as a candidate for colonizability is going to be difficult. Conversely, if we can detect the presence of all the elements necessary for life and industry on a roughly Earth-sized planet, regardless of whether it’s in its star’s habitable zone, we may have a candidate for colonizability.
The colonizability of an accessible planet with a good temperature gradient can be rated according to how well its composition matches the compositions of industrial and biological demandite. We can get very precise with this scale, and we probably should. It, and not habitability, is the true measure of which worlds we might wish to visit.
To sum up, I’m proposing that we add a second measure to the existing scale of habitability when studying exoplanets. The habitability of a planet actually says nothing about how attractive it might be for us to visit. Colonizability is the missing metric for judging the value of planets around other stars.
This raises the ethical question of at which point do we as a race change the environment of an alien world’s biology in order to suit our needs?
Do we engage in biological genicide to seed a planet with Earth-life, or do we adapt ourselves to suit the exoplanet’s environment?
Or do we move on to another planet that is more “colonizable” as Schroeder suggests and totally build a habitat from scratch?
A tale of two worlds: habitable, or colonizable?
Hat tip to Centauri Dreams.
Interstellar Travel and the Long View
From Centauri Dreams:
[…]
Building Structures That Last
A sense of that futurity pervaded our recent sessions at the Tennessee Valley Interstellar Workshop in Huntsville. Several speakers alluded to instances in human history where people looked well beyond their own generation, a natural thought for a conference discussing technologies that might take decades if not centuries to achieve. We talked about a solar power project that might take 35 years, or perhaps 50 (much more about this in coming days).
The theme became explicit when educator and blogger Mike Mongo talked about getting interstellar issues across to the public, referring to vast projects like the pyramids and the great cathedrals of Europe. Cathedrals are a fascinating study in their own right, and it’s worth pausing on them as we ponder long-term notions. Although they’re often considered classic instances of people building for a remote future, some cathedrals were built surprisingly quickly. Anyone who has stood in awe at the magnificent lines of Chartres southwest of Paris is surprised to learn that it came together in less than 60 years (the main structure in a scant 26), though keep in mind that this was partly a reconstruction of an earlier structure that dated back to 1145.
Image: The great cathedral at Chartres.
With unstinting public support, such things could happen even with the engineering of the day, creating what historians now view as the high point of French Gothic art. Each cathedral, of course, tells its own tale. Salisbury Cathedral was completed except for its spire in 45 years. Other cathedrals took longer. Notre Dame in Paris was the work of a century, as was Lincoln Cathedral, while the record for cathedral construction surely belongs to Cologne, where the foundation stone was laid in 1248. By the time of the Reformation 300 years later, the roof was still unfinished, and later turmoil pushed the completion of the cathedral all the way into the 19th Century, with many stops and starts along the way.
Remember, too, that the cathedral builders lived at a time when the average lifespan was in the 30s. The 15-year old boy who started working on the foundation of a cathedral might have hoped to see its consecration but he surely knew the odds didn’t favor it. Humans are remarkably good at this kind of thing, even if the frenetic pace and short-term focus of our times makes us forget it. Robert Kennedy pointed out to me at the conference that the Dutch dike system has been maintained for over 500 years, and can actually be traced back as far as the 9th Century. The idea of technology-building across generations is hardly something new to our civilization.
The ‘long result’ context is an interesting one in which to place our interstellar thinking. Naturally we’d like to make things happen faster than the 4000-year plus journeys I talked about on Friday with worldships, though my guess is that as the species becomes truly spacefaring and begins to differentiate, we’ll see colonies aboard O’Neill-class cylinders holding thousands, many of the colonists being people who will spend less and less time on a planetary surface. At some point, it would be entirely natural to see one of these groups decide to head into the interstellar deep. They would be, after all, taking their world with them, a world that was already home.
Evolutionary Change in Space
Gerald Driggers is a retired engineer and current science fiction author who worked with Gerald O’Neill in the 1970s. I see him as worldship material because he has chosen for the last seventeen years to live on a boat, saying “It was the closest thing I could get to a space ship.” Driggers believes we can begin our interstellar work by getting humans to Mars, where they will be faced with many of the challenges that will attend much longer-term missions. We must, after all, build a system-wide infrastructure, mastering the complexities of power generation and resource extraction on entirely new scales, before we can truly hope to go interstellar.
And what happens to humans as they begin working in extreme environments? Evolution doesn’t stop when we leave the planet, as Freeman Dyson is so fond of pointing out. These are changes that should be beneficial, says Driggers. “Evolutionary steps toward becoming interstellar voyagers reduce the chances for human failures on these journeys. We’re going to change, and we will continue to change as we look toward longer voyages. The first humans to arrive around another star system probably won’t be like anybody in the audience today.” Responding to evolutionary change, Martians may make the best designers and builders of interstellar craft.
Image: Gerald Driggers discussing a near-term infrastructure that will one day support interstellar missions.
Get it right on Mars, in other words, and we get it right elsewhere and learn the basics of infrastructure building all the way to the Kuiper Belt, with active lunar settlements and plentiful activity among the asteroids. Along the way we adapt, we change. Driggers’ worst-case scenario has Martian settlements delayed until the mid-22nd Century, but he is hopeful that the date can be moved up and the infrastructure begun.
All of which brings me back to something Mike Mongo talked about. We are not going to the stars ourselves, but we can inspire and train people who will solve many of the technical problems going forward, just as they train the next generation. One of these generations will one day train the crew of the first human interstellar mission, or if we settle on robotics, the controllers who will manage our first probes. Placing ourselves in the context of the long result acknowledges our obligation to future generations as we begin putting foundation stones in place.
This is not the first time Paul Gilster and others have compared building interstellar ships and matching infrastructure to building pyramids and cathedrals. Both were long range projects in the human past that required multi-generational planning, money, political will and many generations of workers who never saw the end result.
Now, whether interstellar ships will be multi-generation, fast, slow or whatever in the end, they will result from human cultural biases and will be unique in this region of space.
In the end, they will be the result of many generations of human genius.
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