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Extraterrestrial Dispersal Vectors

If human civilization is to extend itself beyond our planet, it will need to take with it the plants, animals and microorganisms that can sustain a living ecosystem. Nick Nielsen argues in this compelling essay that preserving our own species into the remote future thus means preserving terrestrial biology as well, drawing sustenance from it and maintaining it long enough for Earthly systems — and ourselves — to evolve in the myriad environments that await us among the stars. Mr. Nielsen’s examination of future speciation continues his ongoing series on existential risk and the nature of human expansion. You can keep up with his thinking on his two blogs: Grand Strategy: The View from Oregon and Grand Strategy Annex, or follow him on Twitter, where he is @geopolicraticus.

by J. N. Nielsen

Nick-Nielsen

Some time ago on Twitter I wrote, “Astrobiology is island biogeography writ large.” As in the classic science fiction film This Island Earth, we know our world to be an island oasis of life in the midst of a dark and possibly barren cosmic ocean of space. Astrobiology, in seeking to understand the place of life in the universe, seeks to understand our oasis of life in a cosmological context. Perhaps we will be forced to reconcile ourselves with an unrelieved cosmic loneliness; perhaps we will find that life is plentiful in the universe; perhaps life will be found to be so plentiful that it seems likely that life on earth is a consequence of panspermia. Whatever the result of our search, whatever remarkable discoveries we make, complex multicellular life like ourselves is likely to require some kind of homeworld for its initial evolution, and these worlds are likely to be distributed across widely separated worlds. Astrobiology is the cosmic biogeography that can serve as the field guide to this archipelago of habitable worlds.

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The existence of galactic habitable zones (GHZ) and circumstellar habitable zones (CHZ) [1] implies regions of greater and lesser habitability, and the distribution of stars, planets, moons and other matter within the GHZ and CHZ implies worlds of greater and lesser habitability. A recent paper on Superhabitable Worlds [2] has suggested that there may be planets or planetary systems more clement to life than the environment of Earth. This implies the possibility that, although Earth looks like a unique oasis in the darkness of space, it may represent a cosmic region of sub-optimal habitability. At very least, we have much to learn about habitability, given the present necessity of extrapolating from a single data point. It seems, however, than in spite of our ignorance of life elsewhere in the cosmos we must first attempt to map the habitable zones of the universe if we are to search for the life that would supervene upon these habitable zones. The resulting patterns of habitability and life that we will eventually be able to map will be our biogeography of the cosmos – a kind of biocosmography or bioastrography – and we will want to consider the relationship between forms of life that occur at nodal points of habitability, if there are any such relationships.

Biogeographers in discussions of species distribution distinguish between stepping-stones routes, single-step routes, and sweepstakes routes of species dispersal. A stepping-stones route is a gradual process that is integral with the evolution of a species, which expands its range as its population grows, slowly covering a landscape. A single-step route is when, “organisms cross a barrier in a direct, single event, not sequentially.” [3] A sweepstakes route is dispersal via a vector that is rare and unusual. Many islands are eventually colonized by sweepstakes routes, which accounts for their distinctive flora and fauna. A lizard that happens to ride a floating log to an island and finds another lizard of the same species with which to perpetuate the species has experienced a sweepstakes dispersal route. Mostly on islands, one finds insects and birds and marine mammals, and few larger species that cannot fly or swim to the island under their own power.

Astrobiology will need to make similar distinctions among cosmological stepping-stones routes, single-step routes, and sweepstakes routes. We have already begun to understand some of the potential dispersal vectors. We know that a certain amount of matter is exchanged between the planets of our solar system, and it is possible that microorganisms have hitched a ride between planets on rocks blasted off the surface of a planet by some enormous impact. Under conditions prevailing in our solar system, however, we cannot expect that complex multicellular life could expand from our homeworld in this way.

In a superhabitable world or solar system, as noted above, it might be possible for complex, multicellular organisms to follow a stepping-stones route to dispersal beyond their homeworld, and thereby attain a far higher degree of existential viability than they would enjoy if they had remained an autochthonous species of a single celestial body. Apart from superhabitable worlds, on sub-optimally habitable worlds the scenario of single-celled microorganisms living on a piece of ejected debris that eventually finds itself on a celestial body other than its homeworld would constitute a paradigm case of a sweepstakes route.

It is possible to imagine circumstances of superhabitable worlds or even superhabitable solar systems in which the means provided by industrial-technological civilization are not necessary to the dispersal of life to other worlds, and a single-step route may be facilitated by naturally occurring means. In our perhaps sub-optimally habitable solar system, however, this is not possible. For the complex, multicellular life that we know and love on Earth, the only method of extraterrestrial dispersion would be a single-step route, the only dispersal vector would be a spacecraft, and the only way to produce a spacecraft is through a relatively advanced industrial-technological civilization.

Thus the long term existential viability of the terrestrial biosphere is predicated upon the growth and expansion of industrial-technological civilization, which seems paradoxical. In the early stages of industrial-technological civilization, up to and including the present day, the expansion of industrial-technological civilization has come at a cost to the terrestrial biosphere. It has even been suggested that another mass extinction is taking place, an anthropogenic mass extinction, as a result of human activity on Earth. Nevertheless, a vital technological civilization is, at least in our solar system, a necessary prerequisite to the survival of any life derived from the terrestrial biosphere once the Earth passes its natural span of habitability.

It is not only human beings that benefit from space travel and settlement; existential risk mitigation affects every living thing on Earth. If human beings establish a permanent and self-sustaining presence off the surface of the Earth, such an outpost of terrestrial life could only achieve a self-sustaining ecosystem through the parallel presence of thousands if not millions of other terrestrial species (keeping in mind that the majority of these species will be microorganisms, millions of terrestrial species do not necessarily impose insuperable spatial requirements for an off-world settlement). When we go into space, we must take with us the plants and animals that we eat or otherwise rely upon for our existential viability.

If we fail to utilize the resources of our industrial-technological civilization to lift ourselves and our fellow terrestrial species off the Earth, all that has been achieved by the terrestrial biosphere will be lost (i.e., it is not only humanity and civilization that are lost should we succumb to existential risk), except for the possibility of some extremophile microorganisms that might ultimately survive the dissolution of the Earth’s biosphere if blasted into space.

The natural lifespan of the Earth will eventually lapse and come to an end, and after that the natural lifespan of the sun, too, will be exhausted and lapse, which is why Wernher von Braun said, “The importance of the space program is to build a bridge to the stars, so that when the Sun dies, humanity will not die. The Sun is a star that’s burning up, and when it finally burns up, there will be no Earth… no Mars… no Jupiter.” [4] While his expression of the idea is anthropocentric, we can see that any bridge to the stars must also be a bridge for other terrestrial species as well as ourselves. In short, interstellar travel is a dispersal vector for terrestrial biology.

Once our terrestrial biology is extended to other worlds – initially, other worlds in our solar system, and then other worlds orbiting other stars – it will be subject to unprecedented selection pressures, and in the long term these selection pressures will result in speciation specific to the new environments in which terrestrial species gain a foothold. In other words, terrestrial life will continue to evolve, and it will evolve on other worlds in a way that it does not and would not evolve on Earth. Speciation on a cosmic scale will be the result. We do not know and cannot predict the direction that life will take in its adaptive radiation throughout the cosmos.

It will not be until the first terrestrial seeds are planted in lunar soil in a greenhouse on the moon, or in Martian soil in a greenhouse on Mars, that we will know what terrestrial plants grow well in these soils and under these conditions. Only experience can teach us this, as the interaction of organism and environment, especially under novel conditions, is too complex to predict with certainty, and life is a paradigm of contingency, subject to the thousand natural shocks that flesh is heir to.

If this ignorance of the consequences of space settlement for our own biology sounds like I am making light of our knowledge and abilities – after all, human beings have been farmers for more than ten thousand years – the idea is precisely analogous to another challenge faced by space travel. We do not yet know, and cannot predict on the basis of present knowledge of science, technology, and engineering, what technologies will prove to be the most robust forms of propulsion for interstellar vessels. Among the many concepts for interstellar propulsion that have been proposed there remains not only all the science yet to be done to confirm or invalidate the concept, but also the building of specific technologies on the basis of this science, engineering particular vehicles employing these specific technologies, and then the testing and proving of these vehicles in the kind of conditions that will only be faced in flight. In the same way, we do not yet know what terrestrial plants and animals will prove to be robust partners in space exploration.

We may eventually treat our food supply and sustainable ecosystem as an engineering problem, but that will compound rather than limit the unknowns of speciation. Because of our anthropocentric moral standards, we will likely have less moral compunction about modifying other species for their use on space settlements or other worlds; even then, species modified for our use in artificial environments (i.e., on shipboard and space settlements) or on other worlds (initially, Mars and moons in our solar system, and then other planets around other stars) will be subject to a twofold selection process that is only likely to accelerate their adaptive radiation, viz. these two selection pressures being the artificial selection resulting from human genetic engineering of other species and the natural selection of novel environments not encountered by any terrestrial species that remains on Earth.

Notes

[1] Cf. e.g., Astrobiology of Earth: The emergence, evolution, and future of life on a planet in turmoil, Joseph Gale, Oxford: Oxford University Press, 2009, p. 33

[2] Superhabitable Worlds, Heller, René and Armstrong, John. Astrobiology. January 2014, 14 (1): 50-66. doi:10.1089/ast.2013.1088.

[3] Trans-oceanic dispersal and evolution of early composites (Asteraceae) Liliana Katinas, Jorge V. Crisci, Peter Hoch, Maria C. Tellería, María J. Apodaca, Perspectives in Plant Ecology, Evolution and Systematics, Volume 15, Issue 5, 20 October 2013, Pages 269–280

[4] This was quoted by Friedwardt Winterberg at the Icarus Interstellar Starship Congress, Day 2; I have been unable to locate a source for this quote.

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Comments on this entry are closed.

  • James D. Stilwell February 21, 2014, 12:13

    Imagine the 65 million years that alien civilizations have had to step their way across the galaxy star by star….The absence of such civilizations surely means we have some startling revelations ahead: humanity is destined to populate the galaxy, or space travel is far more difficult than we imagine…Perhaps a third alternative to the gloominess ahead awaits us…
    It’s either to the stars or extinction for humanity….
    In the end battling each other with atomic weapons…

  • William Blight February 21, 2014, 12:15

    Direct vector migration will not have to be limited to space craft if we can genetically engineer species that move through space (solar wind or other method). If water bears could be symbiotically mated with a protective shell, a means of space propulsion, and an algae food source, they might be suitable for some island hopping.

  • Ross Harrison February 21, 2014, 14:07

    Paul! I really enjoyed this article. As I read it these thoughts came to mind. When you consider not just the biodiversity of the Earths eco system, you have to also consider the biodiversity of the soil itself. So, in coconsidering the planting of seeds into alien soil even our Moon or Mars we should also consider the transfer of living organism’s that any soul needs in order for a soul to grow. In addition there is the consideration of not just available sunlight but also the proper wavelength if that light thatwould iin courage growth. That an the availability of hydration.

  • RobFlores February 21, 2014, 14:22

    One of the main unknowns in Off Earth colonization, what would happen in worlds that have a 1.1 Gravity . Does an embryo develop normally. If not then there is a strong filter on colonization.
    Because reproduction relying on mutually planned reproduction, requiring
    (going to a special ship/sector for 10-12 months) I think would fail to sustain
    a population. Until you can develop artificial wombs that is, which is by
    no means a “priority research” field right now.

    As an aside : I am of the “Extreme rarity of ETI’ camp. Let me state that
    once we have established colonies on true Earth analogues, we will be
    agents of not just Human expansion, but the expansion of every worthwhile organism we think to bring along. Because domesticated breeds of animals
    are useful to us they hitch along with us. Could you call that an evolutionary strategy, that it become useful to the dominant life form of your home planet and expand as they do. We will be seeding Hundreds of species into
    millions of planets in the distant future. From blue green algae to Redwoods to horses. I am not even including species designed by us to assist in interstellar travel.
    A prior hyper-civilization would have left signs of their dominance, Surely
    when and if we are gone, we shall also, even it’s just some ancient probes and
    lunar footprints.

  • RobFlores February 21, 2014, 16:29

    Damned Blog software ate my symbols.
    I meant the problem of embryo development
    at Greater than 1.1 G or Less than .9 G.

  • Nick Nielsen February 21, 2014, 18:06

    @James D. Stilwell

    I will focus my energies on convincing anyone who will listen that the stars and their uncertainties are to be preferred to the certainty of extinction if we remain an exclusively terrestrial species.

    I note that this simple observation points to a perhaps unappreciated cognitive bias: the desire for certainty over uncertainty, even when the certainty has nothing to recommend it. This might be a good topic for future research.

  • Nick Nielsen February 21, 2014, 18:13

    @William Blight

    Vector migrations without spacecraft is a wonderful idea, and one worth systematically elaborating. This idea is someone similar to the ideas presented by Freeman Dyson in his talk on “Noah’s Ark Eggs and Warm-Blooded Plants” (http://www.youtube.com/watch?v=_yzgPMwshqE). Heath Rezabek brought this lecture to my attention. It is well worth your time.

  • Nick Nielsen February 21, 2014, 18:18

    @Ross Harrison

    I’m pleased that you enjoyed the article, and all of the factors you mention — soil, insolation, light wavelength, and hydration, inter alia — will contribute to the selection and speciation of the cohort of species that will accompany human beings in their adaptive radiation among the stars.

    Seed banks will take on a whole new meaning in extraterrestrial settlements, where they will not only safeguard genetic information and diversity, but will also be a source of proving and experimentation for extraterrestrial agriculture. Working in an extraterrestrial seed bank would be an exciting career, not limited to merely warehousing seeds, spores, and plant germ.

  • Nick Nielsen February 21, 2014, 18:25

    @RobFlores

    Gravitation, like insolation, soil, et al., will be a central selective pressure, but it should be pointed out that we can modify, to a certain degree, these pressures. For example, if gravitation profoundly affected development in utero, pregnant mothers or artificial wombs could be on orbiting artificial settlements that maintained a precise 1G — or whatever gravitational constant proved to be optimal for gestation. This observation suggests that we do not yet even know what gravity is optimal for human reproduction, because we only have our experience on Earth. When human beings and other terrestrial biology begins to reproduce off-planet, we will have a lot to learn about what works well and what doesn’t work so well.

  • Louis Norman wells February 21, 2014, 19:24

    Is it probable that the human species has now evolved to an optimum level permitted by the environmental conditions prevailing on our planet, or is it likely that we have further to go, and in what direction. For instance our life span is a limiting facture in respect of the attention that an individual can give to the evolution of our society in his lifetime. Is it not already a handicap to development of a theory advanced by a particular individual who ,so to speak has,to hand it over to a young pupil to carry further, said young pupil being required to come up to speed before further progress can be made . I f individuals productive life spans were longer could not their specific goals be more precisely achieved in a single attention span rather than two successive bursts of mental effort? is it possible that this could be achieved .

    It seems to me that otherwise progress in deep Space Exploration must inevitably handicapped by reason of the fact that the arena in which we are preparing to launch ourselves is so enormously greater in scale than that in which we have evolved, that unless we are able to overcome either the shortness of our life span or achieve communication rates rates in excess of ‘C’ [Einsteins definition of the maximum velocity of light in a vacuum]we will find it enormously difficult to achieve practical Space Travel

  • Brasidas February 21, 2014, 23:33

    It almost sounds as if you support a form of directed panspermia, with humans sending life to other planets or solar systems. I have often wondered whether this would be a wise hedge against the possibility that earth-bound life never makes it off this small sphere. If we are the only life in the universe, seeding other worlds could preserve this precious gift should humans not be up to giving it first hand. Of course, we would need to come to some agreement to disregard the “prime directive.”

  • Nick Nielsen February 22, 2014, 0:02

    @ Louis Norman Wells

    I think we have much further to go.

    Our solar system will be both training ground and proving ground for spacefaring civilization and the biological adjustments that we will need to make in order to make ourselves into a spacefaring civilization. Distances within our own solar system will be manageable once we get used to the idea of nuclear rockets and accept the associated risks (which is mostly a sociopolitical problem, not primarily a science or engineering problem), and we should be able to enjoy a reasonably rapid commerce among planets, moons, and artificial environments. Our gradually increasing life spans and ability to stay active into later life will easily be sufficient for interplanetary travel.

    Advances in the life sciences and biotechnology are likely to proceed much more rapidly in the coming century than advances in interstellar travel, so by the time we have reached a mature interplanetary civilization, life spans will be far longer and we will be able to have the single, undivided attention span that you mention, and more and better besides. The limit of the shortness of life will be overcome long before the limit of the speed of light.

    You are right that launching ourselves into the cosmos dwarfs in scale all that human beings have accomplished to date on Earth, but our apprenticeship in spacefaring civilization within our solar system will be taking place at the same time that the life sciences and biotechnology are greatly extending the human life span or, alternatively, providing transhumanist alternatives to the biological limitations imposed by our frail, fragile, and vulnerable bodies. By the time we make it out into the wider cosmos, we will be ready for it.

  • Alex Tolley February 22, 2014, 1:41

    While the concept of biological life greening the galaxy is very attractive, it seems far more likely to me that it will be technological “life” that will be expanding into space. Such beings will be designed to survive in space and on any range of planetary environments. There will be no question that such “life” will contaminate other biological worlds, rendering planetary protection issues moot. What form they will take is unknown, but they should become the dominant inhabitants of the galaxy.

  • NS February 22, 2014, 2:59

    Until we know a lot more about what’s out there, we should do our best to PREVENT spreading Earth life to other worlds. Morally and scientifically whatever life exists elsewhere is more important than our need for living space. Only worlds that we can determine are uninhabited should be considered for colonization or seeding.

  • Brett Bellmore February 22, 2014, 3:57

    Experiments have been done for mice, raising them in higher than standard G, in centrifuges. Above 3.5 gravities seems to cause sterility, and 2 gravities allows reproduction at a reduced rate. But it doesn’t seem likely 1.1 gravities would be problematic.

    Our ignorance in the other direction is nearly complete, unfortunately; We know zero G is seriously bad, but have no idea how low gravity can go without serious health consequences.

  • Thomas Mazanec February 22, 2014, 14:32

    Actually, I would expect most life-bearing planets to be sub-optimal. Imagine a bullseye target as the map of habitability, with planets falling at random all around it (and perhaps other targets, for sulfur based or methane based life, for example). The vast majority of planets miss a target…they are lifeless. A few hit a target. But there is much more area in the outer rings, just barely habitable, then in the tiny “perfect” center. So most lifebearing worlds will be marginal.

  • Heath Rezabek February 22, 2014, 15:03

    @NS – The dilemma here, however, is that we have no idea how rare or common life of any kind might be. Our tendency may be to deduce that life is probably far more common than we know. But part of Nick’s point seems to be that left solely to the cradle of Earth, all Earth-originating life is bound ultimately to pass away. As I am fond of saying, the last Bengal tiger on Earth is the last Bengal tiger in the galaxy, simply because there will be no other Bengal.

    Biodiversity in and of itself is a resource worthy of preservation, to my view. But your idea of limiting ourselves to inert worlds for life’s spread seems like a happy medium for the time being. Aside from proposals like Dyson Eggs (above), I also see the asteroid belt as an enticing site for a ring of living archives. (Each biological being is in itself a living archive of its own genome.)

    I explored the asteroid belt option, a bit, in – https://www.centauri-dreams.org/?p=29459

  • Nick Nielsen February 22, 2014, 20:48

    @ Alex Tolley

    While there are reasons to think that machines will have the advantage in space, it depends on what particular kind of transhumanism you subscribe to, if any. While future machines will be powerful, I think that human beings will want to go into space as human beings (I would like to, and I don’t think I’m the only one), and with the proper enhancements, they should be more than a match for machines.

    By the way, I like the phrase, “the greening of the galaxy” and may use it in the future.

  • Nick Nielsen February 22, 2014, 20:52

    @ NS

    It is not necessarily about any human life needing to expand into space, but rather about preserving and extending what may be unique in the universe, which is the terrestrial biosphere. Maybe it is not unique; we are not yet in a position to say. But, minimally, if we can expand terrestrial life to places in the universe now sterile, nothing is lost in terms of the biodiversity of the universe, and much is gained in ensuring the existential viability of terrestrial life, including ourselves and our civilization, which latter may make this existential viability possible.

  • Nick Nielsen February 22, 2014, 21:00

    @ Thomas Mazanec

    I agree that it is likely most habitable planets will be marginally habitable, and for the reason you cite. In fact, this is a perfect illustration of the principle of mediocrity, in a sense in which many have had difficulty applying mediocrity to the Earth and its life. If Earth is sub-optimally habitable despite its obvious habitation, then it is like most of the other sub-optimally habitable planets, and therefore mediocre. However, the fact that most habitable worlds will be sub-0ptimal is not to deny that there may be a few “perfect” worlds in terms of habitability, and they will posses this perfectly optimal habitability by dint of contingency, in the same way that we have inherited a sub-optimally habitable planet by dint of contingency.

  • Wojciech J February 23, 2014, 9:35

    “We will be seeding Hundreds of species into
    millions of planets in the distant future”
    We won’t.
    Terraforming planets is too resource and time intensive compared to building artificial habitats(not even Dyson Spheres but something like O’Neil habitats or Bishop’s Rings) to be carried out on large scale, and alien biospheres are too unique and valuable to be destroyed.
    To travel across the stars you already have to have knowledge how to create a suitable artificial habitat allowing you to survive for generations.
    Either that or you change into post-biological race.
    Both scenarios mean you no longer need planets to colonize or spread across space.
    Sure in early stages of expansion I do not doubt there will be some trying to do this, but in the long term, our technology will make this option obsolete.
    There is no reason to colonize other planets for “living space”.
    As to preserving Earth’s biosphere, that too can be done better in artificial habitats much bigger than any alien planet can provide.

  • Wojciech J February 23, 2014, 9:37

    “A prior hyper-civilization would have left signs of their dominance, Surely
    when and if we are gone, we shall also, even it’s just some ancient probes and
    lunar footprints.”
    Unless we decide not to leave them and conceal traces of our existence in order to allow other potential lifeforms to develop on their own, in unique way, without interference.

  • Tarmen February 23, 2014, 14:48

    If we bring the whole cornacopia of Terran life with us to new habitable worlds , we will unleash a chaotic scramble of competion between species of bacteria, fungus, insects and virus such that the place might become uninhabitable for humans. Ironic. Mother Nature would be happy to have another world with Earth life dna, but it’s no good for h.sapiens.
    We could potentially be out-competed not only by AI machines, but also by other earth lifeforms.

  • Tarmen February 23, 2014, 15:15

    There are bound to be many worlds that colonists will wish they’d never laid eyes upon. They will come to tame a wilderness, but the wilderness will tame them. If there is any pre-existing native ecology, I could imagine our colonists getting totally overwealmed or driven into a niche existance, even devolving into a sick symbiosis with the dominant native life. Scary.

    But what would an IA machine do? Probably stay in space. Or maybe erase existing life and re-seed with earthlife. Yikes.

  • Alex Tolley February 23, 2014, 17:42

    @Nick Nielsen – “greening the galaxy” was a phrase that I first read in Savage’s “The Millenial Project” (I think). He has a picture literally showing a growing mass of green stars in the galaxy, presumably because they are surrounded by his transparent, biospheres.

  • Alex Tolley February 23, 2014, 18:06

    Let me run the scenario to show why I think machines will dominate teh galaxy.

    1. Starships can deliver machines or life at the same speed to a target planet.
    2. Machines can start “colonizing” immediately. Asimovian robots coming off the production line at a fast clip.
    3. Life cannot do this. There are definite reproduction lengths and ecological dynamic rates. Probably the fastest is going to take 1000 years to stabilize, possibly much greater than 10,000 years.
    4. Photosynthetic life is tuned for our star’s output, as are many other signals such as day length for reproduction, full moons, tidal range, etc.
    5. Life should not be introduced to existing biospheres. This does not apply to machines, at least in pre-technological cultures.

    What this means to me is that the narrow range of suitable targets will take a long time to terraform with terrestrial type life. Machines however can colonize almost any target, and very quickly.

    In my mind, the best way to green the galaxy is with O’Neills. They are tailored to Earth life, and any star output can be converted to the correct spectrum. replication happens bay having a mature cylinder split in half and “mate” with a half of a new, raw one, allowing the biosphere to slowly expand into the new half. This cycle repeats when each cylinder is fully mature.

    Are planets the best place for life? I think O’Neill answered that 40+ years ago, in the negative.

  • ljk February 24, 2014, 9:40

    Western science fiction really needs to grow up and get with the times. I know there are exceptions, but most people still think of exploring the galaxy in terms of big starships with a human crew and a hyperdrive, thanks in no small part to SF ideas that go back to the days when computers either did not exist or were big bulky machines that did mainly calculations.

    This is why we have to keep saying over and over that machines will likely dominate the situation, not humans. Sure, we might do some Worldships either privately via some wealthy cult or due to some global effort if humanity is in trouble, but otherwise machines make far more sense.

    It is also another potential reason why SETI has not succeeded so far, the ones who can detect our signals are not interested in talking to us because we are organic (and primitive and young and volatile).

    We need to stop trying to recreate Earth over and over and start using the Universe the way it truly is and functions. The smart species are the ones who have a successful space program and know how to utilize its vast resources.

  • swage February 24, 2014, 11:00

    “It is possible to imagine circumstances of superhabitable worlds or even superhabitable solar systems in which the means provided by industrial-technological civilization are not necessary to the dispersal of life to other worlds, and a single-step route may be facilitated by naturally occurring means. In our perhaps sub-optimally habitable solar system, however, this is not possible. For the complex, multicellular life that we know and love on Earth, the only method of extraterrestrial dispersion would be a single-step route, the only dispersal vector would be a spacecraft, and the only way to produce a spacecraft is through a relatively advanced industrial-technological civilization.”

    I am not so sure. Maybe its impossible for multicellular life, but you made the distinction here for a very good reason – that one being it may be possible for single celled organisms. I am thinking among the lines of life descending on Earth from single celled organisms and single celled organisms carrying the genetic information of multicellular organisms to start the process again. I have doubts about the neccesity for a spacecraft at all. I think the most practical approach would include a molecular assemblers; a Von Neumann so to speak. And, if we look at life as we know it, that’s maybe not totally coincidentally exactly what life is. That being said…

    “Thus the long term existential viability of the terrestrial biosphere is predicated upon the growth and expansion of industrial-technological civilization, which seems paradoxical.”

    …this may also hold true. Being able to specifically select targets enhance chances for a successful colonization effort considerably. Actually the biggest problem with interstellar Panspermia is the chance to hit a target system. The solution may include both elements to a certain degree.

  • Ronald February 24, 2014, 11:05

    Wojciech: “Terraforming planets is too resource and time intensive compared to building artificial habitats(not even Dyson Spheres but something like O’Neil habitats or Bishop’s Rings)…etc.”

    I could hardly disagree more. This is so blatantly and demonstrably wrong and I have argued against this (with estimates given) so many times that I am actually getting tired of it.

    I will just summarize: large artificial space constructs (O’Neill and the like) are, per time and area unit, *vastly* more expensive than terraforming any even remotely earthlike planet. My estimates varied from 10^5 to 10^10 times.
    Hint: calculate the living area of a space colony, plus the total life time (before complete write off), plus the maintenance cost (%) per year. You will be shocked. Very (VERY) expensive real estate.
    Do the same for Mars, a marginally terraformable planet. You will be surprised.
    Besides the fact that colonizing and terraforming a planet like Mars will be an incremental process, going from living domes to more and bigger domes, to complete terraforming.
    Besides the fact that a catastrophy to a space colony could easily result in a total loss. A catastrophy to a settlement of domes is a loss, but not a total loss to the entire planetary colony. And can rather easily be rebuilt.
    Besides the fact that we are humans, with human minds and aeons of human biology behind us. We simply like planets, it’s in our system.

    The only really daunting challenge with terrestrial planets in the galaxy is getting there. Not being there.

  • swage February 24, 2014, 11:18

    “While there are reasons to think that machines will have the advantage in space(…)”

    I think if you go to a certain level, the distinction becomes meaningless. Its all molecular machinery. Nature and Technology are just human designations. My guess is: the more advanced technology becomes, the more life-like it will become. It isn’t actually a clearly defined border.

    “If we bring the whole cornacopia of Terran life with us to new habitable worlds , we will unleash a chaotic scramble of competion between species of bacteria, fungus, insects and virus such that the place might become uninhabitable for humans. Ironic.”

    Introducing complex systems is problematic. I think these things have to evolve from basics to complexity, you can’t simply design it, as it was on this world. Even if the result may be uninhabitable for humans, its still a colonized world in my book. Their destiny is their own, not ours.

  • Alex Tolley February 24, 2014, 11:43

    @ljk The problem for SF is that it is very hard, if not impossible, to write stories that engage the reader from the POV of a machine. A true depiction might be unintelligible to the reader. The only ones that seem to work, IMO, are those that fully anthropomorphize the machine, e.g. Asimov’s R. Daneel Olivaw, or have humans interpret what they see – e.g. Benford’s “Galactic Center Saga” novels, Saberhagen’s “Beserker” novels and Baxter’s “Xeelee Sequence” novels.

    We’re like Devonian fish, trying to imagine the future, glimpsing the possibilities of terrestrial tetrapods, dreaming that suitable mobile aquaria can be developed to allow dominant occupation of the land. Our technology will allow us to build those aquaria, but I don’t doubt that the future will belong to the machine that will be at home in that environment.

  • Andrew Palfreyman February 24, 2014, 11:53

    We sell ourselves short on the available options if we ignore the accelerating future progress of our genetics expertise. This will give us the capability to adapt to many more environments than we otherwise could.

  • Michael February 24, 2014, 13:37

    @ljk February 24, 2014 at 9:40

    ‘This is why we have to keep saying over and over that machines will likely dominate the situation, not humans…

    More likely we will be hybrids with the brain as organic or mostly there of and the rest of us as machine. Maybe we could even have different types of bodies that our brains could be attached to for different purposes.

    ‘The smart species are the ones who have a successful space program and know how to utilize its vast resources…’

    We are still taking the first steps.

    @Alex Tolley February 23, 2014 at 18:06

    ‘Machines however can colonize almost any target, and very quickly…’

    But would they not be aliens Alex, they would not be human and therefore we would be considered as humans, defunct. With that scenario humans would become extinct as surely as we were wiped out by an asteroid.

  • ljk February 24, 2014, 15:21

    Michael said on February 24, 2014 at 13:37:

    @ljk February 24, 2014 at 9:40

    ‘This is why we have to keep saying over and over that machines will likely dominate the situation, not humans…

    “More likely we will be hybrids with the brain as organic or mostly there of and the rest of us as machine. Maybe we could even have different types of bodies that our brains could be attached to for different purposes.”

    Somehow I see organic material as a liability when it comes to deep space exploration and operations. I can see an Artilect wanting to “cut out” the middleman for efficiency’s sake – literally.

    Plus I have to wonder if it will be relatively easier to create Artilects as opposed to transplanting a human brain in a machine body or something similar. And please do not say someday it will happen via futuristic hand waving. Yes that rule applies to me in regards to future technology.

  • Alex Tolley February 24, 2014, 15:47

    @Michael – The unpalatability of a machine dominated galaxy doesn’t make it any less likely.

    @Ronald I think your point is valid, if teh planet is suitable for terraforming, even with technological support (domes, lighting). However, the more un-terrestrial it becomes, the more technology is needed to overcome the differences, the narrower the cost differential. In extremis it may be simply cheaper to dismantle a planet (blow it up) and use its resources for space habitats than to attempt to overcome the problems of colonizing its surface. I also think you vastly underestimate the costs of attempting to terraform a planet as you assume “free” ecosystem resources that would be costly to provide de novo on a sterile world. Automated factory production of habitats may ultimately be relatively inexpensive to produce given access to resources.

  • Tarmen February 24, 2014, 18:59

    I suspect that there are already vast arrays of old old AI machine ‘life’ out there. I would expect they prefer the blue and white star clusters for the raw energy found there. Maybe there will be signitures to detect. Question is… do we want to add more to that? Or do we want to try and establish a niche zone of our organic earthlife colonies. As Alex says, one choice may be easier than the other.

  • RobFlores February 24, 2014, 19:04

    I know that our host PAUL may weigh in on it but,
    Today news from Science Daily that affirms that the Earth Cooled enough to
    have a solidified crust and attained a Hydrosphere, 4.4 billion years ago and In the blink of eye life arose on the earth (160 MYA) thereafter.
    I find the timeline for the appearance of life so soon after the distillation
    of the hydrosphere a somewhat out of boundary event because of it’s speed. I strongly suspect a ready made life form arrived along with all the other debris hitting the earth. One of the main reasons I think this is likely is because while there was relative quiet after the rise of the hydrosphere, it was still a pretty hostile place. Organism living on the earth at that time would have needed good repair mechanisms and be generally pretty hardy. I would not expect a newly risen life form to have such proficient toolkits.
    I think that is one of main weaknesses of the rise indigenous life camp. Any primitive organism would have faced, “being raked of over the coals” to borrow a Hadean term.

  • Brett Bellmore February 24, 2014, 20:38

    Machines, humans, what’s the diff? Compared to inert rocks and blobs of gas, a “machine” capable of reproduction is just another form of life.

    I want life to spread in the universe, I’m relatively indifferent to whether it’s DNA/protein based, or based on solid state memory and 3d printers, or Drexlerian nanotechnology. I’m a lot less indifferent to whether it’s culturally our descendant, whether it’s intelligent, or just dumb replicators.

    In order to meet the universe head on, we will need to be less picky about how we’re implemented. We’ll need to incorporate whatever works into ourselves. If DNA is part of that, fine. But if the universe is conquered by beasts with fusion reactor hearts and carbon fiber bones, who appreciate Nietzsche and Mozart, I’ll consider that a triumph. And if I’m very, very lucky, some part of me will be part of them, if only on the level of data.

  • ljk February 25, 2014, 10:10

    Tarmen said on February 24, 2014 at 18:59:

    “I suspect that there are already vast arrays of old old AI machine ‘life’ out there. I would expect they prefer the blue and white star clusters for the raw energy found there. Maybe there will be signitures to detect. Question is… do we want to add more to that? Or do we want to try and establish a niche zone of our organic earthlife colonies. As Alex says, one choice may be easier than the other.”

    Or way out in the depths of the galaxy far from the center, where it is very cold:

    http://physics.stackexchange.com/questions/69649/thermodynamically-possible-to-hide-a-dyson-sphere

    http://www.space.com/24276-dyson-spheres-how-advanced-alien-civilizations-would-conquer-the-galaxy-infographic.html

    While SETI has not searched nearly as much or as long as people think (50-plus years of sporadic searches from one point in space in a galaxy 10 billion years old and we are still shocked no one has made themselves available?), it is time to get out of the paradigm of Earthlike worlds around Sol types stars and start looking in the places really advanced beings might dwell, as they are the ones we are going to be lucky to detect over any other kind of intelligence, including and especially ones similar to us, which is what SETI has been largely looking for since 1960.

  • swage February 25, 2014, 10:59

    “Somehow I see organic material as a liability when it comes to deep space exploration and operations.”

    *nods* I see the point you are trying to make. However consider this: not only can hibernating organic life beat any kind of technology we can imagine in longevity by millions of years, also genetic code is the most stable form of information preservation known.

    I see you seem to favor machines for their tolerance of hostile conditions, however, as it turns out simple microorganism have the upper hand in this by a wide margin, at least from today’s perspective.

  • ljk February 25, 2014, 13:33

    Swage, I know *simple* organisms can survive all kinds of conditions for millions of years in some cases. But we will need something much more sophisticated and robust for an interstellar mission.

    I know these are not perfect examples, but the twin Voyagers have been operating in deep space since 1977 and the Mars rover Opportunity has been exploring the Red Planet for ten years now. There are other examples, though keep in mind the ones I list were not even designed to go for this long. So imagine if we develop a space machine that is supposed to make it to a nearby star system, with a much more advanced computer brain.

  • david lewis February 25, 2014, 16:35

    I doubt there’re many planets that can be easily terraformed. I also doubt the cost would be cheaper than building a space habitat. Building structures that need to survive hurricane force winds on a 1g world takes a lot of resources. Add in earthquakes and tidal waves and any structure is going to cost orders of magnitude more in effort that building it on a space habitat once the basis of that habitat is built.

    Then there’re the permanent cost of maintenance due to weather. Roads need to be constantly repaired when washed out, and cleared of ice and sn0w. Buildings will need to be handled similarly. Sure, we might have some ancient builds from centuries back, but a planet based civilization is going to be working non-stop to repair and replace their infrastructure at a cost that will be orders of magnitude higher than for similar structures on a space habitat.

    And just how many worlds are going to be earth-like? Odds are their atmosphere will be different. Double the density of the air there and it’ll cost even more to build much of anything. If the wind blows harder then forget buildings of any height. More volcanoes won’t be good either.

    Also a planet based civilization is going to have to deal with practically every form of disaster that would affect a space based one, along with a ton of others. Super volcanoes that could wipe out the crops? Rare, but in the long-term they’re a guarantee. Ice ages? Unless you got control of the climate the whole civilization will have to shift over the ages to avoid being crushed. Asteroids? A space habitat can avoid them, but a planet just has a bulls-eye painted in it with a gravity field that can pull them in with devastating affect.

    Population? The mass of a planet can support a few tens of billions. The same mass would support millions of times that number if in the form of space habitats. A disaster that might wipe out half of the population of a planet based civilization wouldn’t even register on graph that showed the death rate of such a swarm of habitats.

    I suppose people will try and build such planet based civilizations, and that will be their choice. But even a single dyson swarm around a single star will outnumber the people who choose such a life-style.

  • david lewis February 25, 2014, 16:49

    “also genetic code is the most stable form of information preservation known”

    As you said, “by today’s perspective,” but if we ever develop self-replicating machines we will do better. Why use two strands of DNA when we can use four, or eight, or even sixteen…. Such a machine would be nearly immune to mutations. Add in a few processors that do nothing but continuously scan its ‘DNA’ for alterations and it will be immune to mutations unless they’re intelligent and decide to modify themselves.

    If the machines are not intelligent then we could explore another star system simple by sending a single probe, and then having it replicate until it can send several of itself to every body of significance in that system. We escape the problem of worrying about if the probe would miss something of interest by having it look at everything.

  • Alex Tolley February 25, 2014, 17:29

    genetic code is the most stable form of information preservation known.

    It is most emphatically not. Each time DNA is replicated, there are errors. The half life of unprotected DNA is ~ 500 years. Even DNA kept frozen will decay. Compare this with million year storage

    However, that DNA replication error is a feature, not a bug, as microorganisms can “experiment” with errors to find better sequences. The trick with machine storage is to emulate life – not use digital storage to specify the exact planes of a machine, but to store the recipe for building a new one. How we do that with machines is not obvious to me, but some sort of mechanism to allow machines to make variant offspring that can evolve by selection is going to be needed for a machine “civilization”, otherwise it will degrade under replication error propagation.

  • Ronald February 26, 2014, 6:10

    @david lewis: I find your argumentation utterly unconvincing.
    Most of the prerequisites for maintaining a terraformed planet, that you mention, as well as the potential dangers, are exactly what we are dealing with here on earth, and we are doing pretty well :-)

    No, I think that the main challenge in terraforming a potentially suitable planet, after arriving there (getting there is by far the biggest challenge!), will be to get a first foothold, i.e. to establish a base, grow food, become self-sustainable. And ultimately to transform the atmosphere.

    All other basic necessities and natural prerequisites are givens, that define the terraformable planet and are well-known beforehand: gravity, temperatures, the presence of water, geophysical activity, …. We are constantly dealing with this here on earth, what’s new?

    “And just how many worlds are going to be earth-like?”
    That entirely depends on the definition, but probably many will be potentially suitable, basically defined as:
    – within the mass range of an earthlike planet: roughly 0.5 – 2 Me, and of roughly terrestrial density.
    – within the continuous HZ of its (solar type) star.
    – with abundant liquid surface water.
    – with at least a primordial (CO2/N2) atmosphere.

    “Odds are their atmosphere will be different.”
    That is the whole idea of terraforming, see above: a primordial CO2/N2 atmosphere will do fine, we can do the rest, thank you.

    http://en.wikipedia.org/wiki/Terraforming
    http://en.wikipedia.org/wiki/Planetary_habitability
    See especially some of the interesting links therein, partic. Fogg, Ahrens, Zubrin.
    http://www.users.globalnet.co.uk/~mfogg/

  • ljk February 26, 2014, 10:20

    Glass quartz might be best for many millions of years of data storage:

    http://www.theverge.com/2012/9/27/3417918/hitachi-quartz-glass-data-preservation

    The oldest bit of Earth found so far is 4.4 billion years old, a zircon crystal:

    http://www.cbsnews.com/news/4-billion-year-old-zircon-crystal-fragment-is-oldest-piece-of-earth-ever-found/

  • david lewis February 27, 2014, 15:13

    Nothing new, just why bother with the hassle when you can upgrade to something better that can support a few million times the population at a cheaper cost?

    Regardless, planetary civilization, should some people choose to go that way, will just be a niche that would in the end represent a nearly insignificant fraction of humanity. Even if some people choose planets, others will choose space based habitats, and in space there is room for more growth – millions of times more.

    As for dealing with those problems: We haven’t. We have yet to experience a dinosaur killer or, in recent times, a super volcano. Eventually we will. So far we humans have been blessed with a very stable environment in which to develop civilization. Here’s hoping that continues. *crosses fingers*

    As for terraforming a world. In time, should we decide to, a place like Mars might be made inhabitable, but only at great cost and time. In effect we would need more resource than the 7 billion of us on Earth can, as of yet, muster for the project. Terraforming a world tens of lights years away, with travel times measured in centuries would be impossible baring two things.
    1. Either we have some ultra-advanced technology (which we might)
    2. Or there is already a space-based civilization in the system that can afford the cost.

    If it’s the second then it’s already the case that the planet-based civilization will only be a fragment of the larger.

    Of course that is just my opinion, which I can only base on what I know. The links you posted only reaffirmed that opinion. Either way I won’t be around to see how it turns out (much as I would like to be.) All this is just idle speculation.

  • david lewis February 27, 2014, 15:24

    “but some sort of mechanism to allow machines to make variant offspring that can evolve by selection is going to be needed for a machine “civilization”, otherwise it will degrade under replication error propagation.”

    There will only be replication errors if we design for it. If that was the only problems with designing a self-replication machine we would have already created them.

    As for evolving. The machines will be designed, and if they want a new generation that is different from their current one they can (if intelligent) design it. Forget small changing in some code representing their equivalent of DNA. Rather they might start from scratch and redesign everything to better fit any advances in technology. After all, why use processors that can do a billion FLOPS if they got ones that can do a trillion FLOPS. Why use fission for a power source if they’ve made great leaps forward and can use fusion of some sort.

  • Alex Tolley February 27, 2014, 22:32

    @david lewis
    There will only be replication errors if we design for it.
    That seems rather optimistic. replication errors can be reduced (with a cost), but not eliminated.

    The machines will be designed, and if they want a new generation that is different from their current one they can (if intelligent) design it. Forget small changing in some code representing their equivalent of DNA. Rather they might start from scratch and redesign everything to better fit any advances in technology. A
    2 points.
    1. Fully specifying a self replicating machine requires more information that the machine can contain, because it must specify the replicator, and so on to infinite regress. Your fall back is that you don’t have the machine self replicate. Om Earth, the replication chain with self replicating humans, but a machine civ will need to overcome it.
    2. The “recipe” approach top self replication that life uses is very robust. replication errors are not brittle for all but some genetic diseases. This would not be the case for fully specified manufacturing replication.

  • Ronald February 28, 2014, 11:40

    @david lewis: one thing I do agree on, namely that we are speculating. You might, for instance, be right about space colonies, if habitable and terraformable planets appear to be extremely rare and/or if we never find a feasible way of reaching them.
    Other than that, it seems that you put a very great emphasis on (human) population size and its importance for (economic) development. However, I think that for a truly advanced technological civilization population size becomes less and less important for further development. We already see this happening in a modest way: the most properous, developed and powerful countries are not necessarily the most populous. More and more jobs will be taken over by robots and other machines. And technological development seems to become increasingly important for economic development, also relative to population size.
    Therefore, though sustaining a large population may not be a problem for an advanced civilization, I think that attaining the same will not be an objective per se for such a civilization.
    Spreading its life and civilization, and seeding the cosmos seems a much grander goal than just crude numbers of one’s species.