dystopic dystopic

bussard ramjets, cryonic stasis, and exoplanetary colonization

bussard ramjets, cryonic stasis, and exoplanetary colonization

what will it take?

hello everyone,

i'm a bit of a writer, and i can't help but feel drawn to science fiction. that shouldn't be surprising.

lately i've been reading up a great deal on theoretical physics, exobiological speculation, and all that. i was dismayed at first to learn that the chances of faster-than-light travel being physically possible are slim. it was also pretty discouraging when i sat down and looked at the actual speeds that'd be required to traverse sizable parts of the galaxy in a single conscious lifetime. it was a kick when i was down to learn about how difficult terraforming probably would be. but the more i've been learning, the more i've been excited about telling a different kind of science fiction story.

to draw an analogue to our world, the thing that made both the european colonial age and the modern process of globalization have been technology. it's not that we couldn't go to various places around the world before, it just cost too damn much to make anything worth it. i got my BA in sociology, and these sorts of things interest me.

if FTL travel isn't possible, then more than likely it'll be too damn costly to ever colonize beyond our own solar system as the way it's been envisioned in most of the celebrated scifi universes. But there are examples such as Arthur C. Clarke's Songs of a Distant Earth or Sid Meier's Alpha Centauri where humans colonize to escape destruction on earth.

recently i had the chance to meet both Kim Stanley Robinson and Geoff Ryman. Robinson is a hard scifi writer after my own heart; the Mars Trilogy is a really interesting look at our first attempts to colonize within our own star system. Ryman was actually more interesting to talk to, though. maybe because few people have ever heard of him (i was only there because i work at UCSD where he was being hosted). but i actually got to talk to him. he said he thinks we probably won't ever leave our galactic neighborhood.

i'm interested in writing a hard scifi story (or series) myself. i'm interested from a sociological point of view: what would drive us to colonize space? from a writer's point of view, i want to keep the earth around, so i'm not interested in a flight from disaster. what would societies be like after colonies were established? trade would be difficult, but not impossible. same goes for war.

while i'm certainly interested in contributions along those lines, i'm also interested in learning more about the hard science and engineering behind interstellar travel. i've got a lot of questions i haven't been able to answer through wikipedia and google alone. but i'm not about to list them all here.

it seems like a discussion about real ("real") colonization and space travel could use a place on these boards.

i'll kick it off. i've been reading up on propultion especially, and bussard ramjets seem like the most economically feasible option since they gather their fuel as they go - perhaps especially if it could be hybridized with another form such as antimatter-catalyzed fusion. the wikipedia article on bussard ramjets describe that they'd probably need what is essentially a magnetic funnel or ramscoop to gather interstellar hydrogen as propellant.

The mass of the ion ram scoop must be minimized on an interstellar ramjet. The size of the scoop is large enough that the scoop cannot be solid. This is best accomplished by using an electromagnetic field, or alternatively using an electrostatic field to build the ion ram scoop. Such an ion scoop will use electromagnetic funnels, or electrostatic fields to collect ionized hydrogen gas from space for use as propellant by ramjet propulsion systems (since much of the hydrogen is not ionized, some versions of a scoop propose ionizing the hydrogen, perhaps with a laser, ahead of the ship.) An electric field can electrostatically attract the positive ions, and thus draw them inside a ramjet engine. The electromagnetic funnel would bend the ions into helical spirals around the magnetic field lines to scoop up the ions via the starship's motion through space. Ionized particles moving in spirals produce an energy loss, and hence drag; the scoop must be designed to both minimize the circular motion of the particles and simultaneously maximize the collection. Likewise, if the hydrogen is heated during collection, thermal radiation will represent an energy loss, and hence also drag; so an effective scoop must collect and compress the hydrogen without significant heating.


talk about kick-butt imagery! spirals of heated gas careening towards a ship only to be fused and expelled in a jet plume? sweet.

anyway, i've written enough, and i hope it hasn't put anyone off. some of the the community here has proven to be very well read with regard to these kinds of science, so i thought it'd make a great topic for discussion: all things related to space exploration and colonization with reasonable extrapolations of current technology.

my biggest point of curiostiy was with respect to ramjets, so i'll take the kickoff: could the spiral motion of the inbound gas somehow be harnessed to artficially generate gravity by rotating the ship, instead of producing drag?

any volunteers?

final words: i hope no one minds my double-motive. i won't try to steer any dicussion, though if things quiet down i might pose more general questions to keep it going; i encourage anyone interested to pose your own!
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Reply #126 Top
Sorry, but they are very large... this is why the athiest threads are split into about five different threads (I think), or at least that should be why...


yea it is called write so much that no one can follow your point. making you right.


i hope you guys don't take this remark offensively, but: do you think that real understanding comes easy?

it takes a lot of words to make complicated points, and esepcially to explain details. if you leave out the details, you can make mistakes and misinterpretations. while you guys might just want to get to the point, as milltertime said, i'm interested both in writing novels and in learning about things i don't know much about (especially in here, genetics).

and danielost, what millertime said is completely true. sometimes i have other motives, but in this thread i'm not interested in being "right," i'm interested in understanding - and not just the topics we're discussing in here, either.

so i guess all i have to say is this: the only request i have about how to participate in this discussion is to be respectful. if you'd prefer to make short posts, that's fine. i'm sorry if you feel like some posts are too long for you, but out of respect for the people who enjoy longer posts, please avoid givign the appearance of being condescending about it.

PS edit: i myself am very much an intellectual, and i'm prone to being very, very wordy. i try to keep my posts as short as i can without losing clarity, but that doesn't mean they end up short, only shorter.

Dystopic... make a reference to the hitchhikers guide somewhere in there! (a good one preferably) Even though nothing in the guide has anything to do with reality... just please have something in there... plz...


sure the novel has to do with reality. it was really written, wasn't it? so people in a fictitious future could very likely remember it and talk about it. personally, i like it when characters in stories reference other stories, and i think i could manage it. though, i should probably re-read Hitchhiker's Guide - it's been almost 10 years!
Reply #127 Top
I wasn't trying to offend anybody!
You can keep writing long posts, I understand that you need to in order to understand all the aspects of the stuff your writing about.

And I think danialost was making a joke, even though it was wrong.

Though, i should probably re-read Hitchhiker's Guide - it's been almost 10 years!


  

Thanks!
Reply #128 Top
what is the most important phrase in the hitchhikers guide
Reply #130 Top
42, no?

and i believe it's So Long, and Thanks for All the Fish - title of the forth book.
Reply #131 Top
So Long, and Thanks for All the Fish


i guess i actually should have looked it up

let me poke back: are you sure "42" qualifies as a PHRASE?
Reply #133 Top
"We apologize for the inconvenience"

- God's last words to creation
Reply #134 Top
the resources of one solar system nearly die out, it seems to me it'd be exceedingly easy to justify an interstellar war.
yes, but how did you intend to answer the problem of excessive delay? if it takes 100-1000 years one way from system A to system B, how to wage a war? by the time a fleet arrived, it would be obsolete(as stated above) and nobody would be ready for planetary battle.


i'd wanted to come back to this. i indeed posed this challenge to my own imagination. Ender's Game proposes an intersting model for sub-light interstellar war, but it still relied on instantaneous communication and remote piloting.

this might be a longer post, just to warn   i actually want to start with some of the circumstances that could lead to interstellar war.

as we've discussed before, the atmosphere of Mars is much thinner than that of the Earth. about 4 billion years ago, Mars lost its magnetosphere because its core cooled. the Earth's magnetic field is generated because its iron core is constantly churning, as Mars's did a long time ago. this will happen to the Earth one day too; it's believed that our core remains hot because of the energy created by a very large impact that also formed the moon.

that, i think wouldn't be enough in itself to abandon Sol. if we do indeed terraform Mars, i think one thing we'll need to do is learn to create an artificial magnetosphere. i imagine this could be achieved with a satellite network, but i don't know enough of the physics to be sure. if it is possible, then the same thing could be done to the Earth way down the line.

but that leads to another interesting point. i think it most likely that the Sol system would, at any given point, have access to the most advanced technologies. as the center of the Terran diaspora, it'd have the lowest average time to receive transmission from other human settlements, and its history wouldn't be perforated by hundreds or thousands of years of travel through interstellar space, and hundreds or thousands of years of development in a new star system.

still, i don't think war between stars will likely occur unless the potential gains would likely outweigh the costs and potential losses.

there are always freak accidents. at this point in history, we're afraid of a large comet hitting the Earth. but by the time we've got colonies, i think we'd be able to handle something like that, personally. do you?

but i'm going to up the ante. what would happen if a large rogue planet crashed into the sun? or something like that. i need an event that would leave the entire solar system nearly uninhabitable. a rogue planet in itself wouldn't do much to the sun. a small rocky planet would have about as much effect as a drop of acid on the pacific ocean's ph level. a large gas planet would add fuel to the fire. but it'd have to be several dozen jovian masses to make a noticeable effect, at least that's what i'm speculating. but remember, space is big. and unless it were actually aimed, i think it's very unlikely anything would crash right into the sun, or even be moving on the same solar axis. but a planet that massive getting caught in the sun's gravity field would seriously screw up the orbits of damn near everything in the solar system, even if it only passed through once.

keep in mind, this is our solar system i'm envisioning, the origin of humanity. i could imagine us having half a trillion people in the solar system eventually. definately not all on Earth. and on Earth, i think most of the population would be concentrated in massive megastructures in more desolate places.

imagine a golden age of humanity, so to speak. we face a crisis long before we go into space, caused by our own destruction of the environment in many ways, but we manage to come through the crucible, repair the environment as best we can, and give the surface and oceans back to Earth's other life forms. we move as much as we can into the rest of the solar system, and those who do stay on Earth have managed to reduce their 'environmental footprint' to nearly nothing. but it's this event that leads us to see ourselves moving out of the Sol system and colonizing new star systems - for curiosity and security of survival, for adventure and relief of the constant urge to reproduce. that, after all, is the golden rule of all living things, isn't it? don't get me wrong, i myself am a green-liberal type and believe we need to curb our population growth... for now. but i'm a living breathing life form, and i want progeny!

i'm not trying to get into real politics of the present day by any means as an end in itself. i'm just trying to extrapolate from the present, and explaining how i see it to make my extrapolations clearer. i think eventually when technology and culture get to the point - for whatever reasons - that we can preserve the Earth's natural beauty, live elsewhere and believe we've got good lives, and perhaps even learn a thing or two and have some wild adventures - we'll absolutely do it. it'll probably take a whole helluva lot of bickering amongst ourselves, but there it is.

and here comes a rogue planet, alomst on the verge of being a brown dwarf, careeing into our home after millenea of prosperity, hundreds of colonies, and what we'd believed to be a point in history when our morals were finally clear and sympathetic to all and universally true, and our characters pure. we'd be able to detect something that big with our future technology a while before it hit us, it'd catch objects in the Ort cloud and Kupier belt, scattering comets and asteroids all throughout the system in wildly unpredictable trajectories. all of our space-bound infrastructure would be in supreme peril, all the populated planets and natural satellites might potentially have their orbits thrown off, might even be ejected from the system entirely, or crash into the sun, the rogue or one of the gas giants. we couldn't survive that... but we could flee... go somwhere rich. we are the progenitors of all humans, will we live as refugees, or will we retain our noble status? ethical dilemmas as we've never faced, but possibly even millions of years to prepare for what we decide...

* * *

by the way, have any of you heard about the gaping hole in the universe?

edit: actually, this article's better.
Reply #135 Top
and here comes a rogue planet, alomst on the verge of being a brown dwarf, careeing into our home after millenea of prosperity, hundreds of colonies, and what we'd believed to be a point in history when our morals were finally clear and sympathetic to all and universally true, and our characters pure. we'd be able to detect something that big with our future technology a while before it hit us, it'd catch objects in the Ort cloud and Kupier belt, scattering comets and asteroids all throughout the system in wildly unpredictable trajectories. all of our space-bound infrastructure would be in supreme peril, all the populated planets and natural satellites might potentially have their orbits thrown off, might even be ejected from the system entirely, or crash into the sun, the rogue or one of the gas giants. we couldn't survive that... but we could flee... go somwhere rich. we are the progenitors of all humans, will we live as refugees, or will we retain our noble status? ethical dilemmas as we've never faced, but possibly even millions of years to prepare for what we decide...




we would handle this as we handle everything. after it was over pick up the pieces and keep going.

Reply #136 Top
here is a question.


we decide to send a science expedition to alpha. fifty year travail time. how big of a crew do you send. remember too small and they'll kill each other. too big not enough resources. also remember they will probable have to come back as well. ie a generation ship
Reply #137 Top
we decide to send a science expedition to alpha.


use AI.

we would handle this as we handle everything. after it was over pick up the pieces and keep going.


i really don't think we'd recover from that.
Reply #138 Top
use AI.


an AI can tell you if a planet might be habitable. but it can't tell you if you can live there.

and an AI can't handle the unknown and remember the closer it is to alpha the more independent it will have to be. round trip communications will increase to 9 years.

i really don't think we'd recover from that.


as long as we are not completely wiped out we can recover from anything.
Reply #139 Top
what is the most important phrase in the hitchhikers guide


"What is the ultimate question then!?!?"  
Reply #140 Top
an AI can tell you if a planet might be habitable. but it can't tell you if you can live there.

and an AI can't handle the unknown and remember the closer it is to alpha the more independent it will have to be. round trip communications will increase to 9 years.


AI doesn't need to communicate in real time, and sure, sufficiently advanced AI can do all those things and plenty more, not to mention lots of stuff living humans can't do.

as long as we are not completely wiped out we can recover from anything.


nope. not in my story anyway.
Reply #141 Top
nope. not in my story anyway.


even in your story. you can't save everyone. and probable what would happen is they would get out of the way and when it was over come back in hook up with who ever had survived. and start again.
Reply #142 Top
even in your story. you can't save everyone. and probable what would happen is they would get out of the way and when it was over come back in hook up with who ever had survived. and start again.


i simply don't agree. if you want to provide more details as to why you think that, you might convince me, and if you'd like me to clarify any of the points i made earlier i'd be happy to; but otherwise it's simply a difference of opinion.
Reply #143 Top
the problem is you will only have so many years to build enough intersteller craft to transport people to another system. it will probable take 10 years to build and stock such a craft.


the reason people will survive is because not everyone will be living on planets and moons. and the more spacestations you have the more people who will survive. because there would be more stations not directly affected by the brown dwarf. the brown dwarves gravity will affect the whole system yes. but its gravity will only be effective out to a certain range.

and any stations not in the eleptic will probable not be affected by the orbital change of the comets and astroids which are in the eliptic.

and i don't think any humans who were able to get out of the way would just leave these stations without trying to save somemore of them.
Reply #144 Top
fair enough, and i think two clarifications may be in order on my part.

i didn't mean to suggest that Sol would become a 'ghost town' entirely. i'm sure some people would remain, if for no other reason than to maintain the system as part of an intersteller communications network (sort of like the poney express).

there's also a point i made earlier that didn't really consider in your post. with the kind of technology available at that point, i believe the inhabitants of the system would be able to detect the gas mega-giant hundreds, if not thousands of years before it had a major effect on the system. that's more than enough time to build up a truly massive invasion force, esepcially if you don't need to worry about preserving the planets after you leave. i'm sure lots of people wouldn't believe in it, but at the same time, desperation is powerful fuel for a war. the rationalizations for it are huge - if you've been getting reports about these genetic freaks taking hold in some pristine system, and you've got the natural diversity of your home planet to worry about, plus billions or trillions of people to think about, war doesn't seem that unlikely a prospect. that was my point: to imagine the kind of events that'd facilitate an interstellar war, not that we'd abandon the home system entirely.
Reply #145 Top
i don't see us being able to see a brown dwarf for a very long time since it doesn't shine. jupiter is close to a brown dwarf. in fact when they first came up with the term jupiter was considered a brown dwarf. because of the amount of radiation it produces.
Reply #146 Top
if we can see things that are barely big enough to be spherical way past neptune, we'll be able to see something just under a brown dwarf. at the high end, they can be 90 jupiter masses, which would make detecting them fairly easy - we'd see gravitational lensing effects grow exponentially as it came closer. and since i'm envisionthing this at a point when we'd developed interstellar communication, we'd start noticing its effects on EM signals early. and you said it yourself, objects that size emit radiation, though not by means of fusion. visible light isn't the only method we have to "see" things. we can infer the presence of dim objects when they pass in front of bright objects or relatively nearby, affecting their trajectories; we can detect photons across the entire EM spectrum, and we can also use gravitational lensing effects to detect both very large dark objects very far away, and the effects on gravity on objects nearby.

considering the intensity with which we already watch the skies, considering the fact that signal receivers are essentially like highly specialized sensors (especially when something behaves anomalously), and considering that we'll probably continue building observatories of more and more stregth, and have colony ships traveling all over for centuries before, it's a matter of time before some turns up funny and further investigations reveal the existence of a doomsday planet, should one exist.

though, your objections do bring to mind the issue that even if such a thing were discovered centuries ahead of time, people well might not believe it's actually a threat.
Reply #147 Top
In my opinion, interstellar war just isn't feasible without reaching Star Trek-level technologies. Even any sort of relations aren't possible without FTL communications. Really, going out of our system at all is a one way trip, as far as a "hard" sci-fi is concerned (in my definition of "hard", at least). All that would really be feasible is news transmissions, just reports in case anyone wanted to hear the latest events on Earth (ha, I mean ten years old events).

By the way, if you are in the market for extinction level events, might I recommend gamma ray bursts? Gamma ray bursts are the pillars of high energy gamma and X rays that are emitted out of the poles of a collapsing star as it becomes a black hole. Since gamma rays are light, they would be totally undetectable until after they actually struck Earth. These beams, should they strike Earth for a mere 10 seconds, would burn off half of the ozone layer, severely damaging Earth's biosphere, damage which would last for years. Gamma ray bursts can last several minutes, however, so you have convenient options of varying lethality, from atmospheric disruption to total incineration .
Reply #148 Top
In my opinion, interstellar war just isn't feasible without reaching Star Trek-level technologies. Even any sort of relations aren't possible without FTL communications. Really, going out of our system at all is a one way trip, as far as a "hard" sci-fi is concerned (in my definition of "hard", at least). All that would really be feasible is news transmissions, just reports in case anyone wanted to hear the latest events on Earth


well yeah, i think i had all that in mind when i was describing a 'war.' what i have in mind bears more resemblance to a massive number of very well armed refugees, more than a war in the traditional sense. they don't hope to bring anything back to their home system; they're hopeing to take a new home system. i mean, if people in the Sol system had been colonizing nearby systems for a very long time, such that human settlements spread over the space of hundreds of light years, the refugees would be hard-pressed to find worthwhile systems that weren't already habitated. and as we discussed before, given enough time people in different systems might chose to mutate their bodies in different ways, develop seemingly alien ethics and culture - those seem like violitile ingredients, you know?

and it wouldn't be communication in the way we have it now, by no means at all. but i think it'd be a lot more than just news from earth. news, yes, but also new discoveries, further information about destination stars, scematics for new technology, letters from home (family members and decendants of family members). the colony ships and colonies would also be sending back near constant streams of information as well. art, history, new technology, all sorts of scientific discovery and data. i'd bear far more resemblance to the days of sailing ships and (gasp) snail mail, but on a scale we've never experienced. i'm sure some groups would 'drop out' of the interstellar ham radio club, but still i see no reason why communications wouldn't remain open, if not very delayed, among at least some of the colonies.

as for a gamma ray burst, it's an interesting idea, but even if the Earth lost its entire ozone layer, i don't see that as presenting much more of a challenge than terraforming another planet. it'd be disasterous, but it wouldn't cripple civilization throughout the whole system, would it?
Reply #149 Top
as for a gamma ray burst, it's an interesting idea, but even if the Earth lost its entire ozone layer, i don't see that as presenting much more of a challenge than terraforming another planet. it'd be disasterous, but it wouldn't cripple civilization throughout the whole system, would it?


It depends on how much the colonies were supported by Earth at that point. Remember, if you opt for a longer burst that lasted minutes, the entire surface would be incinerated. Earth would be New Mercury. So besides a large portion of humans being destroyed (probably a majority), there would be no supply shipments of any kind, and if Earth was serving as a hub for communications or a remote government, that would be gone too.
Reply #150 Top
It depends on how much the colonies were supported by Earth at that point. Remember, if you opt for a longer burst that lasted minutes, the entire surface would be incinerated. Earth would be New Mercury. So besides a large portion of humans being destroyed (probably a majority), there would be no supply shipments of any kind, and if Earth was serving as a hub for communications or a remote government, that would be gone too.


your point is entirely valid. for the sake of plot, i wanted to imagine an event that'd distrupt the entire system after a fairly advanced level of development had been reached - Mars and possibly even Venus both terraformed, dozens or hundreds of mostly self-sufficient habitation stations in orbit and on the surfaces of other objects, and underground.