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.
Tomorrow I’ll want to take a look at O’Neill’s thoughts on how human society might conduct itself in space, and then return to Ashworth’s ideas on a natural progression to worldships. For now, though, let me give you the reference on Ashworth’s paper. It’s “The Emergence of the Worldship (I): The Shift from Planet-Based to Space-Based Civilisation,” in JBIS 65, No. 4-5 (2012), pp. 140-154. As you can see, the paper puts worldships in the far broader context of humanity’s future in space as we tap new sources of energy and materials. See Astronautical Evolution for more of Ashworth’s extensive contributions to the field.
“-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.”
I tend to agree with this- if there is a structure that has some utility to make it more attractive than a planetary or low grav moon/dwarf planet body. A mega-space habitat doing double duty as a starship is a highly probable possible future.
I always say a spaceship is the best space station.
Watching glass blowers form bottles and considering the solar energy available on the Moon, it may be possible to melt and form huge masses of ore and alloy into hollow structures miles in diameter at the lunar lagrange.
If the Sphere is the strongest and most useful shape (probably) then the 1929 Bernal Sphere may become the most common manmade construction in space. Though Bernal never specified artificial gravity, spinning a Bernal Sphere will provide gravity on the inner surface at the equator. H-b0mbs can accelerate these habitats for interplanetary travel but far more power is needed for a star voyage.
A survey of technology makes the path fairly clear (to me, at least). Beaming energy is the method to accelerate these spheres out of the solar system and slowing them down at the other end is effected with H-bombs. Perhaps practical for journeys to the nearest stars, such slow boats would have very small crews.
If suspended animation is perfected then much longer journeys are possible with much larger crews.
The next century may see unbelievable amounts of energy derived by way of space solar power and the manufacture of small singularities (black holes) for use as Starship engines. This would allow faster ships to overtake the slow boats and transfer the passengers and crew.
The question is how fast these different Starship concepts can fly. Even a black hole drive may be limited to just a quarter the speed of light. However if the higher percentages are attainable then time dilation may allow trips even to other galaxies without needing to freeze the crew. One way space-time treks into the future.
I’m of the opinion that our natural homes in space will be the minor bodies – the asteroids, Kuiper belt and Oort cloud. They represent a vast amount of real-estate; distributed, with no single points of failure.
The corollary to this is that the advances needed to get us out into space are medical, not engineering-based. Radiation resistance and adaption to zero-G; changing ourselves to fit the environments is always going to outpace changing the environment to fit ourselves.
“-changing ourselves to fit the environments is always going to outpace changing the environment to fit ourselves.”
IMO we have bodies that evolved for millions of years in small groups in a certain environment. Since we are not yet able to engineer organisms except as weapons or mass consumption food experiments, I would say we are stuck with changing the environment for quite awhile. Star Travel is in fact a medical problem, not an engineering problem in terms of the need to suspend animation for centuries at a time for voyages to other stars. But interplanetary travel in the near future is not impossible, just expensive. Expensive seems to be the same as impossible to these people who want to send people on joy rides around Mars; there is no cheap.
Vast governmental resources, including nuclear energy, are required to explore and colonise the solar system.
We have the ability to change a weightless vacuum seething with radiation into a spinning shielded habitat offering Earth radiation and gravity. We do not have the ability to change humans into beings that can tolerate vacuum and radiation.
“people traveling to another star will be far more intent on mining asteroids and the moons of planets”
Why travel to other stars at all then? Our own solar system has plenty of asteroids and enough moons to occupy us for centuries or millenia. The only reason for humans to attempt interstellar travel (other than general scientific research) is to find more planets suitable for human habitation. If we merely intend to build space colonies or worldships there’s little to gain by going beyond our own system.
We must also take into account the possibility of a posthuman evolution in those worldships. After all, our flesh evolved in a planetary surface. Gravity systems can be too expensive if they are only needed to keep human bodies healthy and to sustain agriculture. Worldships could became so truly intelligent life, a sort of emerging interstellar life.
Paul, thanks for this — a good summary of what I wrote at somewhat excessive length. But I’ll be watching the comments here for anybody who can find flaws in this vision of our future, because it is after all still pretty speculative. The energy and the matter are out there, no doubt of it, but that does not prove that our descendants will actually be able to use them as I imagine.
Stephen (Ashworth)
Oxford
Some great ideas and comments. And Didac makes me wonder . The worldships themselves . If they are adaptive and self repairing, they may be the ones that make the crossing; with shortlife organisms inside serving in a lesser role, much like the bacteria and virus inside a sea bird. Evolving (or frozen) humans inside an long-lived worldship may be seen as dna. No doubt we’ll bring all the Earth’s dna in a library. Perhaps all living planets inevitably strive to produce worldships as seeds of the planet itself. Maybe we are just enablers. Do worldships mate and procreate ? Or do they just split in half?
We are ready to build that dream now! Our research shows no reason for our procrastination towards the colonization of space. Our technology and understanding of material has matured sufficiently to confidently harvest materials from space, fabricate structural metals (higher quality than on Earth) and construct large structures in space for our future generations to enjoy.
I am a strong advocate of orbital space colonies rather than moon/Mars due to a better 1g environment. I agree with Ashworth that it is a natural progression from orbital colonies to worldships. Our habitat design could house as much as 2million and could easily be expanded and its design can accommodate acceleration with minimal effect to the inhabitants. Eventually, lunar and planetary colonies would be a necessity and our ability to deal with long term health issues of lower gravity should be resolved by then.
What are we waiting for? Per aspera ad Astra
Macrolife?
NS:
“Plenty” and “enough” will never hold up in the face of life’s urge to expand. All the habitable places in the solar system (by habitable I mean suitable for humans to settle, which may well include empty space, some day) will be mapped and allocated even before they become habitable. Not all inhabited right away, but claimed by nations or similar groups, to be ruled, and settled eventually.
There is always a reason to go further: To get away from the powers that be. To settle new ground. To find a place without rules, without taxes, without nosy neighbors. No finite place, no matter how vast, can hold up to this urge for long. Not the Earth, not the solar system, not even the galaxy, ultimately.
You need only drive through the desert between LA and Las Vegas to see this. There are homes there, in the middle of nowhere, with people living in them. There is plenty of space for these people in or near LA, with little to gain by going so far beyond the amenities of the city. Or is there?
Columbus did not cross the ocean because it was too crowded in Spain. The pilgrims did not come to America because England was full. The West was not settled because there wasn’t enough land in the East. The principle is universal, and it would be really strange if it did not extend to space, once technology allows us to go and stay there.
Right now there are humans living in the Space Station. Over time larger and more capable and economical space stations will be made either on our planet or in space. Most probably the next generation of space habitats will be made first from a combination of Earth and space based technologies, and eventualy only from space based activities. I favor the combinational aproach because it is better for the civilization existing in our planet. It does not make much sense to invest. our resources to create space civilizations that will abandon the planet to never come back. A link must be established to guarantee sustainability in our planet from all kinds of space sponsored activities from earth based societies. Our initial goal should be to conquer our solar system first and then go to our nearest star. Our planet should never be forgotten nor abandoned to its luck no matter how tempting space habitats result.
Even the largest of the O’Neill’s was a city sized concept. That isn’t a problem when you are located in the solar system and wish to be part of the expanding human noosphere. But star traveling ships will be mainly cut off from this center of human culture. Is this desirable, especially when the inhabitants have no choice to stay. Imagine the lack of checks and balances on political systems that could make these places living hells. While change can be quick on worlds staying close to the sun, star traveling worlds may need to become very stable and static, and if that stasis is achieved by a nasty social or political attractor?
In a sense, they become stasis bubbles, subject to surprises from the faster developing home culture.
I am a big proponent of this idea. One issue that will take time to work though is scalability of a viable civilization.. not how large, but HOW SMALL How few people can found a viable colony that can replicate a ship or expand to colonies on other asteroids. With support from earth this may be small.. supply everything including life support and one to ten people can be sent around to different sites. This is the NASA model. A colony of fifty suitably equipted can start building and repairing and even harvesting materials for lifesupport and some modest construction of dwellings. this small group would not be able to make digital electronic chips for example without having all the pieces sent over.. right now in our consumer driven civilization the WHOLE plant earth is required to make the trains run on time and supply our ipads. I speculate that this scale can be miniturized a great deal.. Even the pilgrims depended on manufactured goods from England and natives peoples for food. Can we scale our sustained society on a diminutive scale of one million? right now imagine a small country going off the grid. This is a bigger challenge that propulsion for these space based colonies.
As I have argued several times before and at the risk of it becoming a somewhat annoying mantra (my sincere apologies if it does indeed): though I do agree that there is definitely a future for large space stations and space colonies for very specific purposes, such as (asteroid) exploitation and scientific research, and for worldship for the purpose of journeying to other planetary systems, I still strongly doubt that such artificial structures will ever largely or completely *replace* planets as human habitats.
This for two reasons:
1) The cost of such structures (construction, maintenance/repair, replacement) per unit area and time, and/or per person. I would like to see even a very rough estimate of this.
2) The statistically and relatively very great risk of catastrophic failure per time unit. Again, I would like to see an reasonable estimate of this. Particularly, a catastrophic (internal) failure happening in interstellar space might be irrepairable.
Planets are, in comparison, dirt cheap per unit area. And incredibly long-term stable, i.e. total catastrophic failure is extremely rare. And they have the added benefit of a gigantic ‘free’ power source for food and water production. And terraforming can take place as an incremental process.
Of course, admittedly, this all hinges on the availability of potentially suitable planets and our ability to reach them.
Further to my previous comment, I see (near-)future possibilities for interstellar colonization in the combination of radical life extension and perfection of suspended animation (‘hibernation’).
See for instance:
http://nextbigfuture.com/2013/03/safe-sirtuin-activating-drugs-could-be.html#more
In the near future a (healthy) human lifespan of 150 years may be entirely feasible.
And if suspended animation further slows down life’s processes and aging, journeys of several decades to planets around Alpha Centauri or even Tau Ceti may become very doable.
The investments plus accumulated risks of such an enterprise might be much smaller and the rewards much greater, than those of large space colonies and world ships, at least for long-term human habitation.
Eniac said on March 11, 2013 at 22:12:
“There is always a reason to go further: To get away from the powers that be. To settle new ground. To find a place without rules, without taxes, without nosy neighbors. No finite place, no matter how vast, can hold up to this urge for long. Not the Earth, not the solar system, not even the galaxy, ultimately.”
Then of course those who escaped from the oppressive governments on Earth will in turn expand to become the oppressors themselves, forcing groups within their society to chafe at their rule and leave for peace and freedom in turn. The circle of life on a cosmic scale.
The first Europeans to explore and settle North and South America did so for riches, glory, and religious and political freedom, not science. Australia was originally Europe’s dumping ground for criminals and dissidents.
Our first human interstellar explorers and settlers and their motivations will probably mirror their terrestrial ancestors. We have already seen now science takes a back seat to most government space programs, or is used as a front to cover the real geopolitical and military reasons for a space mission.
Artilects probably will do better as interstellar explorers, but there will be attempts by baseline humans to reach other star systems based on ancient motivations. Maybe we can at least convince them (with bribes?) to at least do some science when they get there and beam back the data.
As GaryChurch commented above, space travel is as much of a medical challenge as it is a spacecraft engineering challenge. Here’s what I wonder about: how important is a planetary environment for long-term human health? Consider how much has been learned about the human gut’s microbiome over the past few years. It’s becoming clear how dependent we are on symbiotic bacteria for our health. We get a lot of that microbiome from repeated exposure to diverse bacterial cultures in the food we eat, the water we drink, and the air we breathe. A recent paper, “The microbiome: the forgotten organ of the astronaut’s body–probiotics beyond terrestrial limits” points this out. From the abstract:
In space, the lifestyle, sterility of spaceship and environmental stresses can result in alterations in intestinal microbiota, which can lead to an impaired immunity and predispose astronauts to illness. This concern is heightened by increase in virulence of pathogens in microgravity. Thus, design of a personal probiotic kit is recommended to improve the health status of astronauts. http://www.ncbi.nlm.nih.gov/pubmed/22953705
Taking probiotics in pills may help astronauts, but I wonder if scientists may eventually discover that healthy microbiomes need more than pills — they need the body’s immersion in a diverse, balanced, and evolving ecosystem. As the inhabitants of Biosphere 2 discovered, that is not so easy to engineer in a closed system.
With regard to my remark “Of course this all hinges on the availability of potentially suitable planets and our ability to reach them”;
This just in: “Earth-Sized Planets in Habitable Zones Are More Common Than Previously Thought”, well, at least Earth-sized planets in the habitable zones of M-dwarfs. In fact, as common as up to 40% occurrence rate among M dwarfs.
http://www.sciencedaily.com/releases/2013/03/130312152047.htm
And the research paper itself:
http://lanl.arxiv.org/abs/1303.2649 (the full PDF is available).
The vaulting Ganae spirit:
http://www.facebook.com/permalink.php?id=295129857251950&story_fbid=295131640585105
Ronald , you ask:
1) The cost of such structures (construction, maintenance/repair, replacement) per unit area and time, and/or per person. I would like to see even a very rough estimate of this.
We have determined that the cost to build in space is actually more viable for a large structure than a small one: suppose a habitat to house 1000 people 1kmX200m dia and .5mthick = 315,000m3 or 2.5Mtonnes of steel at $10,000/kg to launch = $25trillion to launch the steel …. not viable at $25billion/person. But if we build ‘large’ enough that we can justify the cost of asteroid mining then we build any size structure for one fundamental cost, the mining and refining equipment. We are building a global cooperative of 350,000 people each committing $75,000 (paid over a period of 25years) to creates a purse of about $26billion over the term. Our estimate are at $500M to build the automated asteroid miner/fabricator and about the same to launch. We would have the budget of several of these. The rare earth and other valuable minerals are returned to Earth adding to our financial resources and our structures are built to any size … at no extra cost except time. Even if the 1000 people built the mining equipment it is still about $1,000,000 commitment each which is restrictive.
2) The statistically and relatively very great risk of catastrophic failure per time unit. Again, I would like to see an reasonable estimate of this. Particularly, a catastrophic (internal) failure happening in interstellar space might be irrepairable.
Not sure what you are asking here but our time scale is about 25years to completion of our habitat once we launch our mining equipment.
A link to our project: http://www.spacedevcoop.com
Eniac and ljk addressed the possible motivation for interstellar travel. Here is another. In his 1984 worldship paper, Anthony Martin argued that societies expand their activities when they can in order to fully employ their capabilities, such as by creating empires. In that vein, he argued further that interstellar travel may ultimately become a necessity simply in order to fill society’s future production capacity — obviously, assuming that growth in the meanwhile has led to a civilisation with vastly greater economic and technical powers and resource bases than at present.
Stephen
Ronald, you doubt that orbiting artificial structures will ever largely or completely *replace* planets as human habitats.
While I would not imagine them completely replacing planets, I would point out the following fact (the subject of another contribution of mine to JBIS). Suppose that it becomes both technically possible and economically affordable to house significant populations in space colonies along the lines, say, of O’Neill cylinders. Suitable resources of asteroids and small moons for constructing such colonies exist in the Solar System, but have a total mass on the order of about a thousandth of that of the handful of terrestrial planets which we might colonise. But the technology of space colony construction would use mass to create surface area with gravity about a million times more efficiently than do terrestrial planets.
Therefore if both types of habitation are in use, the population and economic power will be overwhelmingly concentrated in space colonies, not on planets.
Stephen
Astronist said on March 14, 2013 at 16:27:
“Eniac and ljk addressed the possible motivation for interstellar travel. Here is another. In his 1984 worldship paper, Anthony Martin argued that societies expand their activities when they can in order to fully employ their capabilities, such as by creating empires. In that vein, he argued further that interstellar travel may ultimately become a necessity simply in order to fill society’s future production capacity — obviously, assuming that growth in the meanwhile has led to a civilisation with vastly greater economic and technical powers and resource bases than at present.”
How long would it take to exhaust the resources of our Sol system before humanity would have to move on to other star systems? Assuming humans do not radically change and no method of FTL propulsion is made or found, how many people could the Sol system sustain and for how long?
Another reason to travel between stars is to get out of Dodge before your sun expends its nuclear fuel and ends up as a red giant, collapsar, or supernova. We should be aiming our instruments of SETI at such systems to look for pleas of help, information dumps, and escaping vessels, or some measure of all three.
Stephen,
undoubtedly you are right both in your estimate of available (asteroid, small moons, dwarf planets) material and in your calculation of construction efficiency.
However, my issue was not one of availability of building material, but rather of cost and risk on one hand versus return (living area, life span) on the other. And my argumentation has always been and still is that when expressed in cost per unit area and time, plus (low) risk/(high) stability, (terraformed) planets beat space colonies hands-down.
LJK:
I doubt that bribes will work. When it takes decades for a bank deposit to go through, it is unlikely that Earth currency will be any good in the colonies. And bribery usually requires a quid pro quo, which is hard to imagine if the quid is decades after the quo :-)
But then again, I believe humans will be more than happy to investigate their surroundings, and also to report their findings to whoever wants to listen, even if they are light years away and cannot applaud (or pay). It is what we do. Even if not, as you rightly say, machines will do the job better, anyway, by that time.
@Louis Gelinas
I would say we are waiting for $1 trillion dollars. Well NASA can not even get $10 billion dollars now, and that does not cover doing things like that, but the basic now.
What it will take is many known people coming out making 1 link or so. Donate on this site, or SMS this number to donates $5, different number to donate $100 dollars and so on, and all of US just giving them money once a year. Not saying it, but doing it.
I would give $100 dollars a year if they all come together & made a fund & other people did chip in 2. Not just that, but the people that donate, get there names on a webpage that shows they are the people responsible for this happening / getting it started / done. Would you give $100 a year if everyone does??
We can all site here and hope for it, but if we all give $100 year, we could get this done. Who will finally step up and go public on a big level. All of the people here should, and people like Dr. Michio Kaku / stephen hawkings, and all people popular on these pages & so on should.
Its about them people like that, & docs even saying we can donate . Even docs say there is a site we can all donate, all the money will not be spent but put into a fund that makes interest unto we get it all right “10 year” then its done on a big scale.
With the GOV now, and funding, this and mars and space travel will not happen on a big scale for 1,000 years. Unless we make it happen. Shore there “may be” a fly by in 2020, but on a big scale no way.
Eniac said on March 14, 2013 at 22:58:
[LJK: Artilects probably will do better as interstellar explorers, but there will be attempts by baseline humans to reach other star systems based on ancient motivations. Maybe we can at least convince them (with bribes?) to at least do some science when they get there and beam back the data.]
“I doubt that bribes will work. When it takes decades for a bank deposit to go through, it is unlikely that Earth currency will be any good in the colonies. And bribery usually requires a quid pro quo, which is hard to imagine if the quid is decades after the quo :-)”
I was not thinking actual cash, more like software upgrades and information exchanges, assuming the technology and knowledge gathering of Earth and its Sol system colonies outpace such development aboard a Worldship. Though there is always the chance that some Worldship folks might do it simply out of pure altruism, or indirectly by keeping in touch with folks back on Earth.
“But then again, I believe humans will be more than happy to investigate their surroundings, and also to report their findings to whoever wants to listen, even if they are light years away and cannot applaud (or pay). It is what we do. Even if not, as you rightly say, machines will do the job better, anyway, by that time.”
Humans are naturally curious and big gossips, thus the existence of People magazine and those supermarket tabloids. Knowing your surroundings and reporting your findings to the group have always been important tactical survival skills. Such behavior will be just as important and moreso as our descendants move towards, explore, and settle into literally alien environments.
Scott you said:
“I would say we are waiting for $1 trillion dollars. Well NASA can not even get $10 billion dollars now, and that does not cover doing things like that, but the basic now.”
Everyone knows that NASA is an administrative nightmare. Staff can’t go to the bathroom there for less than $1million!
We have done some serious number crunching and we have over 35years of research into our plans. Yes, an asteroid probe can be made for way less than the $800M that NASA budgets for the Osiris Rex. If all the material for our probe were made of solid gold, I still couldn’t get anywhere near there costs. Here is an interesting (somewhat dated) look at the cost of rockets:
http://www.fourmilab.ch/documents/rocketaday.html
Our asteroid miner is estimated at about 50-75,000kg much of which is proven technology here on Earth only built of composites materials instead. One can easily calculate those cost differences. at $10,000/kg (and dropping) launch cost we need $500-750M to launch our under $500M miner.
$500Million is a lot of money and in any industry other than “space” and it would build amazing stuff. One could build an enormous condo hi-rise for that kind of money and there is no reason that a simple mining extraction system and mineral separation and basic foundry cannot be built within that budget. As more private sector money is invested into space development you will see a rapid drop in overall project costs.
Check out what these guys are doing on a very limited budget:
http://www.copenhagensuborbitals.com/
Don’t forget that our project is a cooperative and that part of the membership requirements are 10hours/month of labor. This means that with 350,000 members, we have 3.5million man hours of “free” labor. That is over 20,000 full time staff equivalent. At $10/hour …. you can do the math. Much of our costs can be deferred.
ljk: the basic material resources of rocks and metals remain in orbit indefinitely, and are indefinitely recyclable. Volatiles would gradually leak away or be used up in propulsion systems, and I’ve not attempted to estimate how long the Solar System’s volatiles could support a large population.
Our Sun is not going to end up as a supernova, but will go thru red giant and white dwarf stages. Even the red giant stage will develop fairly slowly on a historical timescale. I see no reason why civilisation should not persist in orbit round the Sun for tens of billions of years yet. Do you?
Stephen
Ronald, clearly we will have to wait and see what the relative costs and practicalities of terraforming planets and building space colonies turn out to be. I think that space colonies have the advantages of being relatively small and quick to construct, and the resulting environment easy to control. You think that once a planet has had Earthlike conditions installed, then it will be easy to maintain those conditions indefinitely. The future needs entrepreneurs like both of us to try these ideas out in practice.
Stephen
Astronist said on March 16, 2013 at 18:20:
“Our Sun is not going to end up as a supernova, but will go thru red giant and white dwarf stages. Even the red giant stage will develop fairly slowly on a historical timescale. I see no reason why civilisation should not persist in orbit round the Sun for tens of billions of years yet. Do you?”
Do you really think a species like ours could survive a star in its red giant or white dwarf stages? Granted whatever might still be living in the Sol system five billion years from now will certainly not be us, but seeing as the red giant stage will either vaporize or melt any worlds close to it and the subsequent white dwarf will not have enough energy to support anything that isn’t orbiting very close to it, I would think that any species which could migrate to another star system with a younger and more stable sun would not hesitate to do so, rather than ride out these volatile solar stages. They will have to leave anyway when Sol finally goes to the black dwarf stage.
Stephen/Astronist,
agreed!
But I admit just loving that line from Aliens (the 2nd movie): “… (name of the company), building better worlds”.
:-)
The assumption, I think, is that by then people will be able to live off worlds, so the melting of planets will not affect living conditions very much at all. There will be only one time when there is sudden change, and that is during the explosion (nova or supernova?). Presumably that will not come unexpectedly and our descendents would be temporarily crowding into the shadow of sufficiently distant gas giants to ride it out. All other times, gradual adjustment of orbits will take care of any changes in the sun’s behavior.
Really? Every single one of them? To me, it seems, that staying and coping is the easier option, so most will do so. On the other hand, many will also leave, probably well before any impending disaster, for any number of reasons.
Remember, species to not have to leave when they go, as individuals do. They have a tendency to go and stay, both. It is called spreading, and we are very good at it.
“Granted whatever might still be living in the Sol system five billion years from now will certainly not be us,-”
Time dilation throws all assumptions like this out the window. Traveling close to the speed of light, travelers could return to Earth billions of years in the future while only a few years have passed onboard their starship.
So not certainly.
GaryChurch said on March 19, 2013 at 19:04:
“[LJK] Granted whatever might still be living in the Sol system five billion years from now will certainly not be us,-”
“Time dilation throws all assumptions like this out the window. Traveling close to the speed of light, travelers could return to Earth billions of years in the future while only a few years have passed onboard their starship.”
Not quite. A human starship crew that traveled to the Andromeda Galaxy and back at 99 percent light speed would age 56 years, while everything on Earth would be over two million years older than when they left.
Eniac, while I am sure that some folks will stay even under the worst circumstances despite the risks to themselves and their companions – like the old guy who lived in the shadow of Mount St. Helens and would not leave his home (he and his home are subsequently buried deep under the results of the volcano’s spectacular eruption in 1980) – I would have to wonder about the benefits of staying in a system where the main star was dying, especially trying to maintain an energy source and adequate protection.
Eventually Sol will become a black dwarf (is that the right term for a really dead star?) and its retinue of worlds will drift off into the galaxy. Maybe these stayputers will like living deep within a planet or moon as it roams off into deep space, but then again they may be the same kind who like living in artificial circumstances just like Asimov.
“-and back at 99 percent light speed would age 56 years,-”
I did not say anything about 99 percent- you did.
If you go faster time dilation increases.
LJK: There is only a very short period, once, that the sun will not be stable for countless millennia into the future. Yellow main sequence, red giant, white, yellow, or brown dwarf, who cares when it takes many millions of years for the changes to even be noticeable? The sun will not go “black” for trillions of years. There is never an urgent reason to leave, because it all happens so VERY slowly, compared to our lifetimes.
Except, admittedly, for that one time when the sun goes boom. That one time may well be reason to leave, but it can also be sat out a lot closer to home than a distant “nearby” star. In the shadow of outer planets, or in the interior of Kuiper belt or Oort cloud objects, where the increased sunshine during the nova phase might even be welcome. I will not venture a guess what percentage of the population will chose the interstellar trek, but I am willing to bet a large amount (in nova-time dollars) that it will not be everyone.
Also, consider, that all of those “nearby” distant stars will already have been settled by those who did not want to wait around for the catastrophe. They would by then be every bit as populated as our system. Perhaps a wave of trillions of bedraggled alien refugees would not be welcome.
“Perhaps a wave of trillions of bedraggled alien refugees would not be welcome.”
We would probably exterminate the natives; our only other option might be extinction. We think it would be a difficult choice but in the event there would be little debate.
Tall order, that. A little bit like Great Britain sending an invasion fleet to exterminate the Americans, today. Not going to happen, even if the Brits were desperate because their Isles just sank into the North Sea. Clearly, they would be better off braving the immigration lines rather than trying to “exterminate the natives”
Even a trillion people in ships have very little chance against a trillion people entrenched in their system with all the industrial resources under their control. Of course, it depends on the relative technological prowess, but chances are that information exchange will have made that about even, and in any case I would give the former colony a better than even chance to be the more advanced. Kind of like Europe and the US, only on a larger scale…
I think when talking about a stable space based species, you have to think big.
Once you get a foothold, so you can live, procreate, prospect, mine, refine, produce and build in space, you can keep developing and expanding non stop. The resources in between planets and stars are nearly unlimited. Growth would be slow at first but would gain pace exponentially. Within a million years such a species should be found being spread around thousands of star systems with millions of city sized ships. They would dwarf any planet based civilization.