Posted on 01/13/2016 9:28:58 PM PST by LibWhacker
It's a common theme in science fiction, but migrating to planets beyond our solar system will be a lot more complicated and difficult than you might imagine
The idea that humans will eventually travel to and inhabit other parts of our galaxy was well expressed by the early Russian rocket scientist Konstantin Tsiolkovsky, who wrote, “Earth is humanity’s cradle, but you’re not meant to stay in your cradle forever.†Since then the idea has been a staple of science fiction, and thus become part of a consensus image of humanity’s future. Going to the stars is often regarded as humanity’s destiny, even a measure of its success as a species. But in the century since this vision was proposed, things we have learned about the universe and ourselves combine to suggest that moving out into the galaxy may not be humanity’s destiny after all.
The problem that tends to underlie all the other problems with the idea is the sheer size of the universe, which was not known when people first imagined we would go to the stars. Tau Ceti, one of the closest stars to us at around 12 light-years away, is 100 billion times farther from Earth than our moon. A quantitative difference that large turns into a qualitative difference; we can’t simply send people over such immense distances in a spaceship, because a spaceship is too impoverished an environment to support humans for the time it would take, which is on the order of centuries. Instead of a spaceship, we would have to create some kind of space-traveling ark, big enough to support a community of humans and other plants and animals in a fully recycling ecological system.
On the other hand it would have to be small enough to accelerate to a fairly high speed, to shorten the voyagers’ time of exposure to cosmic radiation, and to breakdowns in the ark. Regarded from some angles bigger is better, but the bigger the ark is, the proportionally more fuel it would have to carry along to slow itself down on reaching its destination; this is a vicious circle that can’t be squared. For that reason and others, smaller is better, but smallness creates problems for resource metabolic flow and ecologic balance. Island biogeography suggests the kinds of problems that would result from this miniaturization, but a space ark’s isolation would be far more complete than that of any island on Earth. The design imperatives for bigness and smallness may cross each other, leaving any viable craft in a non-existent middle.
The biological problems that could result from the radical miniaturization, simplification and isolation of an ark, no matter what size it is, now must include possible impacts on our microbiomes. We are not autonomous units; about eighty percent of the DNA in our bodies is not human DNA, but the DNA of a vast array of smaller creatures. That array of living beings has to function in a dynamic balance for us to be healthy, and the entire complex system co-evolved on this planet’s surface in a particular set of physical influences, including Earth’s gravity, magnetic field, chemical make-up, atmosphere, insolation, and bacterial load. Traveling to the stars means leaving all these influences, and trying to replace them artificially. What the viable parameters are on the replacements would be impossible to be sure of in advance, as the situation is too complex to model. Any starfaring ark would therefore be an experiment, its inhabitants lab animals. The first generation of the humans aboard might have volunteered to be experimental subjects, but their descendants would not have. These generations of descendants would be born into a set of rooms a trillion times smaller than Earth, with no chance of escape.
In this radically diminished enviroment, rules would have to be enforced to keep all aspects of the experiment functioning. Reproduction would not be a matter of free choice, as the population in the ark would have to maintain minimum and maximum numbers. Many jobs would be mandatory to keep the ark functioning, so work too would not be a matter of choices freely made. In the end, sharp constraints would force the social structure in the ark to enforce various norms and behaviors. The situation itself would require the establishment of something like a totalitarian state.
Of course sociology and psychology are harder fields to make predictions in, as humans are highly adaptable. But history has shown that people tend to react poorly in rigid states and social systems. Add to these social constraints permanent enclosure, exile from the planetary surface we evolved on, and the probability of health problems, and the possibility for psychological difficulties and mental illnesses seems quite high. Over several generations, it’s hard to imagine any such society staying stable.
Still, humans are adaptable, and ingenious. It’s conceivable that all the problems outlined so far might be solved, and that people enclosed in an ark might cross space successfully to a nearby planetary system. But if so, their problems will have just begun.
Any planetary body the voyagers try to inhabit will be either alive or dead. If there is indigenous life, the problems of living in contact with an alien biology could range from innocuous to fatal, but will surely require careful investigation. On the other hand, if the planetary body is inert, then the newcomers will have to terraform it using only local resources and the power they have brought with them. This means the process will have a slow start, and take on the order of centuries, during which time the ark, or its equivalent on the alien planet, would have to continue to function without failures.
It’s also quite possible the newcomers won’t be able to tell whether the planet is alive or dead, as is true for us now with Mars. They would still face one problem or the other, but would not know which one it was, a complication that could slow any choices or actions.
So, to conclude: an interstellar voyage would present one set of extremely difficult problems, and the arrival in another system, a different set of problems. All the problems together create not an outright impossibility, but a project of extreme difficulty, with very poor chances of success. The unavoidable uncertainties suggest that an ethical pursuit of the project would require many preconditions before it was undertaken. Among them are these: first, a demonstrably sustainable human civilization on Earth itself, the achievement of which would teach us many of the things we would need to know to construct a viable mesocosm in an ark; second, a great deal of practice in an ark obiting our sun, where we could make repairs and study practices in an ongoing feedback loop, until we had in effect built a successful proof of concept; third, extensive robotic explorations of nearby planetary systems, to see if any are suitable candidates for inhabitation.
Unless all these steps are taken, humans cannot successfully travel to and inhabit other star systems. The preparation itself is a multi-century project, and one that relies crucially on its first step succeeding, which is the creation of a sustainable long-term civilization on Earth. This achievement is the necessary, although not sufficient, precondition for any success in interstellar voyaging. If we don’t create sustainability on our own world, there is no Planet B.
Baby steps, first a Moon Pie then a Mars bar then a Milky Way.
Discovery of some sort of warp in space-time "wormholes" or the like to jump the distances. Otherwise the relativistic time issues are going to create a bunch of totally disconnected nodes of humanity never to contact each other again. Once someone has left, that is it. No further contact, ever. in a useful manner. Radio conversations with multiyear pauses between replies do not work so well I should think. And that would be for close neighbors.
>What Will It Take for Humans to Colonize the Milky Way?
A lot of Mars Bars. ;-)
IMHO, the whole enterprise is “beyond imagining”. The reality of these distances conquers any notion we may rationally maintain of traversing them. I may cite the Fermi paradox ... where is everybody?
“Forget arks. We’re going to have to do it with speedy starships, so that people can get there in a couple of years (ship’s time), or not at all. And before we do that, robotic scout vehicles are going to have to check the planet out first to determine its habitability. Condemning generations of unborn innocent people to spend their lives in some nightmare, totalitarian prison ark is inhumane, unethical in the extreme.”
An asteroid the size of Ceres has been calculated to provide as many hectares/acres of arable land inside the asteroid as all of the arable land on the Earth. Such a craft would be a mobile world rather than a restrictive prison. A cavern space wit a ceiling about 700 meters in height is sufficient to give the impression of a blue sky, while centrifugal force provides a substitute for Earth’s gravity necessary for good health.
Ummm, I think we have already colonized the Milky Way. It is called Earth.
Never happen, we will not go back to the moon, or ever try for Mars. After Jesus comes and kicks some evil bootay yes. Man by himself, we are too busy fighting each other and always will be.
It's only a matter of time until some rebel physicist breaks the universal speed limit of 186,000 mps, then all bets are off. The whole universe will open up for the humans of this little mud ball we call planet earth.
Lol!
There was a time when humans couldn't imagine distances we routinely travel today. The same will hold for the future, which is endless. We've literally got forever to figure this stuff out - and we will.
Well, we have to go back to the moon first. It’s been almost 50 years since we’ve been there. Currently, the U.S. can even refly John Glenn’s mission without paying for a Russian seat. :-(
Immortality.
Thanks to Obutthole, who had the gall to cite the U.S. space program in his rant last night.
After the first few colonies, we can automate the process.
Send a colony ship with self-replicating robots to do all the work of building habitats, stockpiling fuel and materials, making air and water, raising food, and then terraforming the new world.
Once everything is ready, take some embryos out of the freezer and raise the kids (a great clone army). Call home and report in, or lay low and try to hide from the government (no reason to think they will be any better then).
Then start building and launching an endless stream of further colony ships.
Repeat exponentially.
Let us not be unkind to creatures beyond our realm, and restrict human perfected suffering and misery to our own planet.
Excuse me, but I'm hard put to name what these unimaginable distances are that we routinely travel today, since we haven't left the earth since Apollo.
“where is everybody?”
The vast majority of extraterrestrial Life can be expected to be single cell like forms, which you cannot expect to be attempting to communicate. Where the more complex multicellular lifeforms exist and developed into sentient beings, there is still the problem with overlap in time and space. Humans have been aware of the radio spectrum for only an instant in time. There are innumerable reasons why the Universe is teeming with Life and we would not yet detect it.
I think the answer is suggested in the Bible. The answer is not to try and go faster than the speed of light, but to stay still and bring the mountain to Mohammed, so to speak.
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