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Humans Will Sail To The Stars
oddsheep points to an "article on BBC news from the AAAS Expo in Boston about how researchers are discussing spreading the human race across the galaxy in solar sailing ships. Not a new idea of course but the social implications discussed are great: what the hell do the volunteer colonists (and their descendants) do for the hundreds of years it would take to get anywhere? Cue "Are we nearly there yet?" from the back seats ad infinitum and the longest game of 'I Spy' in history..."
It would seem that the people on the ship would have a lot stronger sense of forward history. Say, generation two of ten, for a long voyage, they'd understand the critical nature of conservation, preservation, and making sure that their children's lives aren't for naught.
There are many science fiction stories about "people born on the way," in ark-like ships of this sort.
What strikes me is the sense of drama and tragedy if the on-ship culture panics or corrupts itself before it reaches the goal. Does anyone know of any stories that focus on that? Where generation eight of ten finds that they need to scrap the historic goal, due to some miscalculation or some unforeseen hardships, or merely a decadent generation five?
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what the hell do the volunteer colonists (and their descendants) do for the hundreds of years it would take to get anywhere?
Do what people do now to kill lots of time: play games or hack on the next open source project.
Heh. I wouldn't be very concerned about the boredom level of the colonists... I mean, if we were going to build such a big spaceship, it wouldn't be much of an extra cost to give them:
a) A digital collection of the complete works of art of Humanity (you know, something to read in the way), and
b) A laser-link or something similar to give them fresh news (inasmuch as 50 or 60 years old news can be considered "fresh").
What I would be concerned is to how to convince their descendants to continue the work started by their parents. No matter how sophisticated the ship's systems may be, there's always gonna be the need for knowledgeable people to keep them in shape, or as backups, or something.
"But I really want to be a... ballerina!",
"Shut up, John, you'll be a cooling system engineer just like your father was, and his father before him, and so on".
Of course, we could end up with something similar to Robert Heinlein's "Universe", where the descendants are so remote from the original colonists that they don't even know they're on a spaceship.
Tongue-tied and twisted, just an earth-bound misfit, I
Learning to fly, Pink Floyd.
Even if such a voyage were possible and volunteers do (which is bound to happen), we must seriously examine how mentally flexible they are and how adaptable would they be to a hostile environment with no longer the comforts of yellow sunlight bearing down on them, and fresh air carrying the scent of flowers around. More so, how comfortable would they be with co-existing with each other, since it is imperative that in a situation such as this, the common good far exceeds the individual benefits accrued.
After the colonists spend a few centuries or millenia traveling to another star system, their society will have adapted to life in space. They'll have become emotionally acclimated to living in a confined habitat surrounded by vacuum, and they'll have learned the technical skills necessary for survival there. Hell, they'll probably be agoraphobic.
So why bother going back down and living on a planet again? Any other star system will have enough comets, meteors, and other matter to provide plenty of resources for the colonists to live. Why go back down to a planet to live in a gravity well and have to deal with all those scary wide-open spaces?
TheFrood
If you say "I'll probably get modded down for this..." then I will mod you down.
...or at least 80, according to an article at New Scientist.
However, there could be a slight problem with inbreeding. From the article:
"The decrease in genetic variation is actually quite small and less than found in some successful small populations on Earth," he says. "It would not be a significant factor as long as the space travellers come home or interact with other humans at the end of the 200 year period."
"It remains to be seen if the human brain is powerful enough to solve the problems it has created." Dr. Richard Wallace
(What follows is a joke. Laugh)
I have a theory. We Americans are the descendents of the people too screwed up to make it in Europe (my anscestors were expelled from Britain for participating in a political revolt). So you have a bunch of crazy Americans living on the East Coast. Some of them were too screwed up to make it there, so they went further and further west. Which is why California is so fucked up.
Think of how reckless and dumb you'd have to be to get on board one of those ships. Do you really want to populate the galaxy with people like that?
That brings us to our possible problem. Do reall you want to populate the world with the kind of people that are reckless and dumb enough to get on board that ship? I don't think so.
Steve
A consequence of human intelligence is that it encourages individual selfish behavior. Extending the domains of the human race suddenly takes a very very low priority, well under personal and tribal survival, personal ambitions, plain convenience and indulging our laziness.
What do we care if the Van Neumann machine is a more efficient AND effective method of colonizing the universe?
The humans on those planets will not be "us". They will never have had direct contact with Earth, and probably would be quite different from what we consider human unless we provide very strict controls... and hope they work 300 years and some light-years away with no intervention.
Why do we care about interestellar travel at all? It's not really to spread mankind through the universe; we already have seen how much enthusiasm we have even for a measly solar system.
We care because WE WANT TO BE THERE. Personally, if possible. Symbolically, at least, through direct descendants that we can see growing and becoming "us". At the very, very least, we want to give ourselves the illusion that we're part of the trip by climbing on a ship and going away.
The Van Neuman machine has all the romanticism of the postal service, therefore people won't care, therefore no decent resources will be assigned to such a project. It may be the intelligent solution; so was automated exploration of the solar system.
No, what we're currently doing does not count as systematic exploration of the solar system anymore than your high-school chemistry lab is doing serious research.
Freedom is the freedom to say 2+2=4, everything else follows...
Saying we will sail to the stars can be likened to the inventor of the zepplin saying that we will have mass crossings of the atlantic via deridgible.
Not even the ultra skeptical Nasa believs this solar sail stuff, which is why they are working on the REAL way that people will colonize the stars, with next generation propulsion systems.
These new systems are to chemical rockets as the sails of sea ships are to the jet; profoundly differnent and unpredicted by the "scientists" and sailors of old.
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You could never put several generations of humans on some form of interstellar ark and then have then continue as they had on Earth once they got there. A couple generations removed from the rest of human society would cause them to develope independantly from the rest of the human race both physically and socially. As an example many cultures cremate or bury their dead after performing some traditional rite. This is unrealistic in a self contained environment thus the dead would be recycled to eventually become food for the living. Lets say a voyage was launched tomorrow, how much do you think the culture on the ship would change in 20 years after several people died from various causes, natural and unnatural. A whole dogma might form around the mere act of eating, on an ark you would be eating the remains of your dead* on a daily basis. In a hostile environment (which deep space certainly qualifies as) the weak either die or become a burden on the rest of society. Unproductive members of society would be a waste of resources. Like samurai warriors or elder Eskimos ritual suicide would be a common and revered cultural dogma. Any culture being sent into the wilds of deep space would not have an analog back on Earth, in fact they would be almost an entirely new culture, a result of people adapting to a dangerous environment.
.99999999c that way it will only take me about 8.5 years ship relative to shoot out of the other side of the galaxy. That's one fast rocket monkey.
Thus it is of my opinion that sending people to the stars without a warp drive does little to preserve a culture or way of life which when it comes down to it is the only real difference between any of us. Spaceborne cultures would not resemble anything we've seen here on Earth specifically because they weren't born there. If a decendant of some space colonist were to meet a human from Earth they would be as alien to them as anything else dispite the similarity of their DNA and maybe even the fact they share a common ancestor. It wouldn't matter what you did to prepare people for the rigors of a generations long journey into space they would become wholly alien to anyone back here.
As for the technical feasibility of enormous solar sails propelling people to stars that is 99.99% bunk. The people envisioning such systems disclaim their theories by saying "if we could only find a way..." which usually requires something along the lines of changing the physical laws of nature. I'm sorry but even the magical properties of carbon nanotubes isn't going to solve any inherent problems in using a giant physical structure to capture photons. I groan every time I see this idea rehashed. The key factor in sails all of all sorts if the ratio between the sail surface area (for much force is can use for propulsion) to that of the overall mass of the craft (how much force it needs to get going). While a giant solar sail might work fine for sending a ship to Mars (albeit a small one), getting megatons of personnel and equipment outside the solar system is another matter entirely. The sail needed for a colony ship would be stupendously large which means increased mass and you guessed it needs more force to get it moving. The bigger they are the bigger they need to be to have the energy to get them going. Say the ship is heading to the other side of the galaxy and a solar sail ship is doing about 10% lightspeed by some means. Relative to the rest of the universe not doing 10% lightspeed the vessel would have to survive 600,000 years worth of cosmic travel without something going HCF. Even with relativistic time dialation which would only save you about 2,390 years ship relative off of the 600k that is still quite the feat. Humans not frozen, kept in some form of stasis, or otherwise inert would have evolved into a completely alien species by then. Shit it'd been only recently the last of the other monkeys in our genus died out. Wake me when we hit
I'm a loner Dottie, a Rebel.
And once you get outside of the solar system (say one light year from the sun) you actually have the galactic wind exerting pressure towards our sun.
As for the radiation, yes the earth does a pretty good job. You could use an artificial magnetosphere to shield against the solar wind, but power failures do happen, and you still have cosmic radiation (which is the bigger problem). Our atmosphere is equivalent to 13 feet of concrete WRT shielding cosmic radiation.
One thing is clear: long-range manned spacecraft are going to be big and heavy.
OTOH, solar sails could make for very low-cost, light-weight probes (without chemical or ion engines and fuel tanks). And they could still be useful in giving an initial boost to manned ships.
Did you know you can fertilize your lawn with used motor oil?
It would appear that this poster didn't even take the time to read the article. In fact, the term "solar sail" is somewhat misleading, because the scientists quoted proposed using directed pulses of light from lasers to propel the interstellar craft. The 1/r^2 law is only true for isotropic radiation -- not for a directed laser beam, which can remain well-collimated over great distances.
This idea is not at all new -- I recall reading essentially the same notion as a high school student in the mid-1980s in a book on solar sails. Some futuristic plans included building a massive bank of lasers on the far side of the moon. While we are still very far from realizing such dreams (as we will need the infrastructure in place to support such a lunar base first), I always thought that such ideas were intringuing, and provided a physically viable mode of transporting large payloads, to say, Mars, and the outer solar system.
Lastly, I should also point out that it appears that this author doesn't even understand the basic physics of conventional solar sails. Solar sails use light pressure from the sun, not the solar wind itself. The pressure from the hot plasma streaming from the solar wind is orders of magnitude smaller than the light pressure. Light pressure is also tiny, but since your net velocity is proportional to the time exposed to the source of light, you can build up significant velocities over weeks or months. A great number of people extend the "sail" analogy a bit too far.
Bob
Science, like Nature, must also be tamed, with a view turned towards its preservation.
The chance of a collision with asteroids is very minute. There are actually very few significantly sized asteroids, and they are spread over an enormous volume of space, generally concentrated between Mars and Jupiter. If you don't believe me, just consider that any number of space missions have made it to the outer solar system by now. JPL has launched Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Galileo, Ulysses (on a gravity assist to get to the sun), and Cassini (now halfway between Jupiter and Saturn), and none were taken out of commission by an asteroid (though Galileo had unrelated problems).
Dust and micrometeorites are a much bigger problem, especially since they are distributed throughout space, and the further your mission travels, the more material you will inevitably sweep up. There is an interesting solution here, though. Although the article refers to laser-pulsed sails (in the visible range), it is also possible to use masers (in the microwave range). Since a "good" reflector need only be smooth to within a wavelength of light, a maser sail would only have to be smooth to within a few mm or cm. Not only would this enable you to save greatly on the mass of the sail by using a conducting "spiderweb" sail, which would be mostly empty space, but the sail would also be greatly resiliant to many small dust impacts.
Whether such a design is actually feasible for an actual mission is not immediately clear. However, the distribution of dust sizes in interstellar space is well-known to astronomers, so it would be very straightforwards to study the "damage" done to a sail, as a function of the speed of the vessel. (I'm sure someone has done this...)
Bob
Science, like Nature, must also be tamed, with a view turned towards its preservation.
Even in the remote chance that we do develop a manned space ship that is capable of supporting generational travel to some nearby part of the galaxy, then unless there's something terminally wrong with planet Earth, it's more than likely a ship which is twice as fast will be developed within the next decade. Before the first ship even arrives at its destination, we would most probably have a ship that could make the journey there and back in less than half the time.
It's kind of like imagining what would happen to a family who got lost on a small self-supporting island (a family who could not make radios out of coconuts) during the late 1800's, and being found by GPS or satellite photos somewhere in the 1980/1990's.
The technology of any offworlders we send out into space will be obsolete a year after they have left, let alone generations. So is there any point in sending people until the travel time is negligable ?
As you get nearer to the other star, you'll have to turn it around, and let it start decelerating.
You've gotta decelerate if you don't want to just shoot through the other system.
However, there are some tricks you can pull to slow yourself down faster than you get started, and thereby spend more time going faster and get there sooner. For example, you can use a big loop of superconducting wire to transfer your momentum to charged particles. Space isn't all that empty, and you can get drag in an imperfect vacuum if you try hard enough. You might even manage to scoop up propellant to finish braking maneuvers.
Another trick: imagine two mirrored sails forming a right angle. Now imagine that light is coming from both sides equally. Aim the point of the wedge at the destination star, and the light from it will be redirected to the sides, while the light coming from the departure star will be reflected straight back, resulting in a net gain of momentum towards the destination star. With this system, you can get forward acceleration about up until the light from the destination is double the light from the departure point. You can up that by bringing the sails closer to parallel, but you lose area as you do that.
Such a trick might not be worthwhile, of course, since light intensity drops off pretty quickly with distance. You'd get most of your boost early on. As a double-whammy, as your velocity increases, your driving light will red-shift, reducing its pressure, while your braking light will blue-shift, increasing its pressure.
However, as the pressure reduces, you might be able to increase sail area by reprocessing structural support into sail surface.
Maybe some nice people back home will let you leave a system of mirrors (or perhaps solar-pumped lasers?) to focus the sun's light on you as you go, and keep the pressure from dropping off. If you can do that, you can have almost constance acceleration for the trip, which is really nice for space travel. OTOH, how much do you want to trust the people of Earth not to redirect your system for their own transportation or power generation?
It's a thoroughly interesting topic.
I admit that it was a few years since I studied the theory of relativity, but I belive it is you who don't know your physics.
Either I've been suckered by an elaborate multi-person troll, or you're both arguing the same thing: travel fast and the people back home are a hell of a lot older than you when you get back, but you aren't much older at all.
Although I was under the impression that teh Edge of the Universe was defined by photons travelling at the speed of light away from the big bang, and that it is therefore impossible to ever catch up to them...
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Benjamin Coates