For propulsion around the solar system:
“Project Orion”, q.v. (Google or Bing “Project Orion Loomis” if this is meaningless to you, but then please read beyond what first comes up. Dig deep! it’s worth it!).
For interstellar propulsion:
same answer, except use fusion devices, instead of fission ones.
Eventually: there are possibilities beyond H / Li fusion devices, but that’s for later.
For payload: initially, Orion-type vessels; eventually, Oort objects to which fusion propulsion systems have been attached.
It’s all entirely feasible — even now — technically, at least.
Why not? What do you all think we — the “human race” would have to overcome, how would we have to grow, to mature, in order to unite and take advantage of this technology, so clearly and immensely superior to our weak little chemical rockets, and so clearly and immediately possible?

Thanks to all of you in advance for doing the homework, and commenting. When I was a child, I dreamed of such travel; I will never see it happen in my lifetime, but perhaps our children, or our children’s children, or children’s children’s children, might…

So yes, immortals perhaps, in the beginning then. But they will be competing for the resources soon enough.

Hmm. Seems selection always win out in the end. :-~

With the advances in technology, it is inevitable that aging (as we know it) will be eliminated, and as a consequence future space colonization prospects become more reasonable.

That’s a toughie.

No organism has evolved functionality for being individually immortal, because it was quite opposite to the process how populations survive (individual differential reproduction).

And obviously evolution is more efficient than stagnate immortals, because where are they? (That SETI question again!)

To change our irreducibly complex cell functionality to do that now is likely impossible.

But it is claimed at least one cnidarian have evolved _a process_ making them immortal, or so it is believed. I don’t remember the species name, but IIRC the trick is that the jellyfish back up all or most of its cells to an adolescent state and redo much or most of the development again. That we can do to individual cells too now (albeit not in situ)!

Of course, the jellyfish will eventually do that to its neuronal cells as well to regain youthfulness and that was observed IIRC, so it wouldn’t be “you” if applied to a human. It would at best be “your twin baby brother/sister” all over again.

But if we forget about exact individuality and try to do a “Peter Hamilton”, say. (Spooling of neuron states near enough that a “repatterned” clone would accept continuity however flawed in functional and memory detail. No worse experience than waking up.) Would that “immortality” be feasible?

Yes, but only if we retain sex and have that infinite colonization wave! (Presumably with infinite life times we can imagine licking galaxy barriers. Say, taking a black hole and enough mass to shoot at it for energy while in intergalactic transit. With a whole solar system that we “coax” by gravitational assist.) Incidentally, I can live with both. (^o^)

This is why I’ve always felt that the most fruitful next step for manned space travel is the development of low-earth orbit longterm habitats, and not flashy projects like going back to the moon or mars.

I’m all for that. (Though I reserve the place for some flashy exploration projects in between.)

LEO tourism could be incentive for Moon exploitation (fuel!), then Moon tourism, NEO exploitation, et cetera.

@ Mikey G:

We have yet to successfully see a mammal get pregnant, gestate, give birth, mature, get pregnant, and give birth again in Outer Space…Until that happens, we ain’t going anywhere.

Quite possibly true, but now you are talking sex technique. :3

More to the point, inside a hollowed asteroid or comet (Oort object), there will be the same type of volatiles, refractories, acceleration (centripetal to make up for microgravitation) and radioactivity as here.

My point was that before we can make it a billion years that we have to make it through tomorrow morning. To that end, it is better to look to tomorrow which will be a factor in our survival whereas things happening a billion years from now will not affect us (and yes, I intend to be around by then, just not in this present form ;-).

In Solomon it says to not invite the troubles of tomorrow into this day since the troubles of this day are enough.

Amphiox suggested that bypassing asteroids and the moon was a better option for our inevitable future space explorations. If I get his/her thinking right, it is predicated upon the idea that to reach the resources of space we must live in artificial structures for entire life times. While I agree that is the case, I’m proffering that it is too soon to worry about such things. To me it’s much more important to exploit the resources that are attainable in this era than to plan for an era that is at least decades away.

Like you I believe our next step is the moon. I meantioned arteroids in that one, it is a survival benefit to know how to move them and two, it is a big lump of shielding already in space that doesn’t need to be lifted to orbit.

If it seemed as if I disaggee with what you wrote, I was unclear because I think we are on the same page.

Thank you for your thoughtful input!

[q]
However, to divert resorses that could be better used now toward some unthinkably distant future is error.
[/q]
What of the short term benefits? There is already a corporation trying to gain permission to build a ring of solar panels on the moon, which in theory could provide all the energy needs of earth. Would this not be a really beneficial use of resources? Would it not require a leap in off world colonization technology?

[q]
Why would we seek to waste all the protection and resourses offered by settling upon even an asteroid? I mean, at the very least there is a hunk of rock that can at least partly shield us from radiation and insulate us from the cold and vacuum of space, right?
[/q]
No one is saying we should. Off world colonization is the priority, but there are many methods to achieve this. Colonizing an asteroid is just another method that if proven viable, will most likely be invested in.

I was the first to publish (and maybe the only one to this point) the easily implemented plan of having a fleet of a thousand space stations ping ponging from Jupiter to earth to transfer momentum from Jupiter to earth to lift earth out to the orbit of Jupiter in the short period of a billion years.

That’s a very interesting definition of “easy” you’re using there!

Although with a couple billion years of projected progress to play with I’m sure it will be quite feasible (assuming projected progress of course), but with that same time frame of projected progress we should expect to have lots of options to choose from.

I should point out that moving earth outwards might work for the expansion into red giant phase, but then what? What happens a billion or so years after that when Sol shrinks to white dwarf? When the white dwarf cools to black dwarf? When the solar system gets irradiated by a nearby GRB or supernova, or has a close encounter with another star or black hole? (on long enough time scales such an event is inevitable – if you’re planning on surviving all the way to Sol’s white dwarf stage you’ll have to account for it)

On the very long term, we have to cut the umbilical to the planet. We have to reach a stage where individual planets, and even individual stars, just don’t matter.

We have yet to successfully see a mammal get pregnant, gestate, give birth, mature, get pregnant, and give birth again in Outer Space…Until that happens, we ain’t going anywhere.

There is no physiologically coherent reason to suggest that this will be an absolute barrier. The potential complications that we can currently foresee (changes in gravity, radiation exposure, etc) are all very solvable.

If thinking we will survive to a billion years as a species comforts you in some way, I really see no harm. However, to divert resorses that could be better used now toward some unthinkably distant future is error.

Why would we seek to waste all the protection and resourses offered by settling upon even an asteroid? I mean, at the very least there is a hunk of rock that can at least partly shield us from radiation and insulate us from the cold and vacuum of space, right?

To my mind, there is much to be gained by learning to exploit resources in space to facilitate present life on Earth. That way IF the distant stars ever get within reach of mankind, we will have knowledge and technology to exploit them to our benefit as well.

As for self destruction, I first heard about Mutually Assured Destruction when I was five years old. I thought it over for a bit and proclaimed that no one was stupid enough to blow up the whole world.

I’m glad that so far I have been right!

Nobody has discussed that because it’s rhetorical and can never be tested or confirmed.

If we can survive the next 100-200 years, it is probable then that we will survive indefinitely. This is simply the result of our likelyhood to have offworld colonies by then, which no single apocoliptic event even a nuclear war could destroy.

http://www.youtube.com/watch?v=zSgiXGELjbc

This is why I’ve always felt that the most fruitful next step for manned space travel is the development of low-earth orbit longterm habitats, and not flashy projects like going back to the moon or mars.

Because from these habitats, we get space colonies, and over time, solely due to human nature, and not requiring any special government/political impetus at all, some of these colonies are going to want more self-determination and independence, and they will invest on their own volition in making themselves self-sufficient from earth. And at least some of them will eventually get to the milestone of complete self-sufficiency, where they no longer require any input of resources, energy, or people, from earth, again solely because of human nature and again requiring no special government investment. And once that happens you just have to stick an engine onto such a colony, and you have a generation spaceship and you can go anywhere, absolutely anywhere you want in the universe. (We can go to the moon and mars then with ease, of course, and do everything we want to do on those two worlds, without having to spend a single dedicated red cent on it – we’ll get all the science and exploration for free, basically, if we aim for colonization as the primary goal first in this way). You won’t even need relativistic speed. These colonies are going to become growing, almost organic entities, moving from resource source to resource source, expanding themselves as their populations expand, and on occasion even self-replicating by building new colony ships for their excess population. They will diffuse out of our solar system as naturally as the first cells diffused out of the primordial hydrothermal vent (or wherever else abiogenesis began).

In fact, biologists seems to find that gene-cultural evolution, along with the increased efficiency of selection in a large population, is speeding up our evolution compared to other species.

When we colonize space, we and our kept biospheres will diversify into many descendants. And the universe will be richer for it.

The other non-argument against colonization:

too far away for us to colonize

You should look at xkcd comic posts of universal distances. On a log scale it is the distance to the Moon that is the hardest step, IIRC. The step to Oort cloud objects is about the same difficulty when we come so far, seeing that resource and technology base expands exponentially.

Oort objects contain many Earth masses (well, ~ 2, but who is counting “many” :-o) of volatile and refractory resources to sustain a colonizing civilization. Fissionables (already licked problem) or fusion (seems lickable) will have to provide energy to make up for the lack of solar energy.

Our Oort cloud is predicted to seamlessly mix with the surrounding stars. In fact, it is believed that ~ 10 % comes from other stars, and in turn makes up for our own losses at the gravitational borders of the system.

Hence a colonization wave can continue indefinitely, stepping from comet to comet and use them their innards for habitats or habitable vehicles. After that first long step, no one will be further away in the log scale. And especially if you live in your vehicle, what does time and distance really mean?

It is dubious if such galactic colonists would want to make the expensive descent into deep gravity wells of Earth analogs. Further, those giant habitats are too large and too dependent on stars – they are uncontrollable drifters – such clumsy design! But hey, maybe those descendants too will be as curious about “the next place”.

Human beings have evolved to live with earth conditions. They are not adaptable to other planets with different atmospheres, gravity, temperature or lack of water.

And what do you mean by “earth” conditions? The conditions we “evolved to live with” no longer exist. They changed hundreds of thousands of years ago, and continue to change every day. And we have adapted and changed with them. When we leave this planet and find other places to live, we will adapt to the conditions we find. If we do not, then we will die.

Making “things work here at home” is not a viable longterm option. Because earth will not continue to have “earth conditions” forever. If we’re lucky we’ll have at most 1 billion years. If we’re not lucky, we may have no more than 300 million years or so. (This has nothing to do with the death of the sun, by the way, but just its normal evolution as a normal G-type main sequence star. Earth will turn into something like Venus some time between 300 million to 1 billion years from now. Barring massive geoengineering on a scale we are not currently remotely capable of, and which may or may not even be possible at all, that much is guaranteed.)

And if we’re very unlucky, or very stupid, it’ll be only a few centuries.