To the Stars!

[Donegeal]

The article of the '10 year long Civ II game' and recent personal Civ games where I make it my goal to win via Spacerace, has got me thinking: What would it take/How would we get a colony on a habital exoplanet?

For the sake of this particular argument, we'll go with the assumption that suspended animation is not feasable.

[Elok]

An asteroid headed for Earth, big enough to destroy all life and too big to destroy, seen coming with plenty of time. That's the most feasible scenario to overcome the political difficulties under our current understanding of physics, IIUC. Ask Lori or somebody about the scientific difficulties, but I think they're beside the point.

[/killjoy]

[Donegeal]

The political and economic aspects/difficulties are something that I hadn't really thought of and I was wondering more about scientific difficulties, but delving into them as well could be interesting.

Hmm... just thinking about the political aspects a little bit makes for some major hurdles to overcome. Lets hash them out as well.

[Elok]

Well, assuming AC's got a viable planet on it, that's...Wiki says it's four light years, if I'm reading it right. That's a couple of decades for people to spend on a ship just waiting for the thing to get there. Even with relativistic whatchamas, that's a considerable amount of one's life to sacrifice. I imagine we'd have to send a probe first just to know if the planet's viable, and the combined times mean the colonization of AC won't happen in either of our lifetimes unless we make some major longevity-boosting discoveries or revolutionize our understanding of physics. Or both.

With the nearest hope so far away, any colony will be effectively cut off from Earth. The expense and time required to reach it will make any commercial enterprise implausible; I don't think any known resource, in any concentration, would be worth such investment. It would take four years and more just to send a message, then another four to get a reply. As far as our planet is concerned, the people sent to AC would no longer exist. And that's why I'm pretty sure it won't happen; it's a massive, long-term investment that will produce nothing to benefit the investor beyond the satisfaction that human beings will exist somewhere so far away it boggles our comprehension. We managed to gin up the cash to land people on the moon, but that's a pitifully minor accomplishment by comparison, only took ten or so years to plan and about a week to accomplish, and we can actually see the celestial body we landed on with the naked eye. Despite that, we lost our enthusiasm for it quickly.

A more interesting idea, to me, is underwater cities. The technological and political barriers are far lower, the environment is far more viable, and it might even be cost-effective under the right circumstances.

[Guynemer]

When it happens, I'm joining the Gaians, because I want those creepy ****ing worms on my side.

[Elok]

Screw that, I'm with Lal--"the sane, emotionally balanced person's choice."

[loinburger]

Assuming no suspended animation and no way to bypass special relativity, I'd say the only scientifically feasible way to colonize another planet is to send over a bunch of frozen sperm and unfertilized eggs and have the ship be completely automated. As to how you then go about robo-teaching the artificially fertilized/gestated children, I dunno. I just don't see a way to keep humans alive for hundreds or thousands of years on the spaceship(s), and even if you can keep them alive then you can't keep them sane.

Having an automated ship might also let you get there faster (more acceleration is possible if you don't need to worry about crushing everybody on board), though I don't know how much of an advantage that would be on a centuries-long flight - if your engines are running all of the time at full blast then you're probably going to quickly run out of fuel. Hydrogen fuel obviously isn't going to cut it - you'll probably need some sort of solar sail or whatever, in which case you won't have much acceleration.

[Donegeal]

Actually, Elok, it would take significatly longer to get to AC than a couple of decades. The fastest spaceship to date was Helios, and it went upwards of 150,000 MPH. Going that fast the trip to AC would take over 170,000 years. Whatever ship goes to AC, would have to go significantly faster for it to be even a remote possibility.

I also think you are on to something about the economic returns on the trip. While the actually colony and ship would have no monetary return, the technologies gained in trying to get there could be exploited for profit (simlar to how some aspects of the movie Contact went). So one of the economic questions would be: Could companies get a profit out of the techs needed to go to AC?

Underwater cities are a great idea! So great, you should go start your own thread!

[loinburger]

In Alastair Reynolds's "Revelation Space" universe they manage to achieve speeds of around .99c simply by accelerating at 1G for a long time - if the journey is going to take you several years then you've got a long time to accelerate. (You've also got to spend a long time decelerating, though.)

In Larry Niven's "Ringworld" they have faster-than-light travel, but there's a species of extremely cautious aliens who refuse to use warp travel because of its dangers. In order to migrate to the edge of the galaxy (due to a disaster in the galactic core expected to reach them in the next 10,000 years) they take their entire star with them.

[The Mad Monk]

Did he address the increase in the mass (and the consequent increase in power required to maintain constant G) as the ship approaches c?

[loinburger]

No, he gives the ships magical engines (they're powered by a wormhole that tunnels to the instant after the Big Bang or some such nonsense)

In later books he also gives the ships magical inertia-reduction technology

[Donegeal]

Glad you mentioned Niven and the known space universe. That happens to be my favorite. Now aside from stepping disks and the FTL travel, Niven has a tendancy to to stick to Hard Sci-Fi. The early space exploration in the Known Space books, was done with Bussard Ramjets (the idea that if you are going fast enough already, you can collect enough hydrogen in interstellar space to fuel your engine). I believe that this type of engine is actually possible, but we just haven't developed the tech yet. Any of our physists out there know the feasabilities of a Bussard Ramjet?

[loinburger]

90% of the atoms in the interstellar medium are hydrogen, but according to Wikipedia up to 70% of the medium has a density of less 10^-2 atoms per cubic centimeter (liquid water is 10^22 atoms per cubic centimeter) which probably isn't going to cut it. It might be possible to pilot your ship through denser areas, but again according to Wikipedia only 1-5% of the medium has a density greater than 1 atom per cubic centimeter, so you're probably going to be taking a lot of detours to keep your ship fueled.

Intergalactic travel using such a method would be impossible - the average matter density is one proton per four cubic meters.

[Elok]

I was assuming we would just accelerate like a mofo with ion drives or something. I'm no scientist.

[Donegeal]

I wouldn't think steering the ship at those velocities is very practical.

http://answers.yahoo.com/question/in...5152446AAiNpnk

You appear to be right.