rosborne979 wrote:Setanta wrote:Our own Roswell wrote:I would also point out that even without Von Neumann machines, all it would take is one single technological civilization (with a healthy desire to reproduce and the inclination to colonize), to cover an entire galaxy within 10 million years (even without suprauminal drives).
This suffers from the same naivete as Fermi's original question.
No it doesn't.
All I stated is a fact related to travel times and sizes. I also stated that I was assuming a technological civilization with the desire to colonize.
You followed with a whole slew of assumptions which may not apply to alien civilizations. How do you know they don't have a religious imperative which drives them to colonize at any societal cost. Or a biological imperative. You don't.
A technological civilization with a desire to colonize is still going to be limited by factors which are unavoidable. To create a viable colony, you're going to need large numbers of people, to assure genetic variety, and to assure that sufficient survive the slings and arrows of outrageous fortune so that the colony can eventually prosper.
Large numbers of people going into interstellar space immediately face two problems which cannot be ignored--weightlessness and cosmic radiation. Weightlessness can be dealt with, to a limited extent, with artificial "gravity"--and that means a significant increase in material and energy costs. You can either expend a huge amount of resources on providing an "artificial gravity," or you can go really, really fast. Large material and energy costs would be required for either alternative.
Cosmic radiation is a serious issue which the lovers of science fiction never deal with (and that's not a specific reference to you, so don't take it personally). To negate the effects of cosmic radiation, you'd need huge shielding, which would increase material costs by orders of magnitude. It would also increase the cost of lighting payloads out of the mother gravity well, even if only the raw materials to be assembled in orbit.
The other way to combat cosmic radiation is to mimic the system that we have on earth--to create a magnetic shield to envelope the colonizing craft. Huge energy and material costs once again.
So what it gets down to, is that people who like to imagine that colonizing the stars can be quick an easy with just small increase in our technological sophistication are ignoring basic problems of what we can call "human nature" and some hard realities of the cosmos.
For example, you continue to see a technological civilization as a monolith in which all the members have the same ideas--such as your reference to a religious devotion to the notion of colonizing. Would that mean the entire population of their home planet? There would be no heretics? All cultures on the home planet have exactly the same religious views? The one example of a technological civilization about which we know anything--our own--is not an encouraging example for imagining ant-like cultures in which all the members think the same way and work happily toward whatever goals the leadership sets them.
It is as naive to make such assumptions, and i would argue more naive, than it is to imagine that our civilization is a good template for how technological civilizations arise. If your imagined civilization has a religious devotion to colonization, how was the level of fervor maintained over the what doubtlessly was the centuries from the completion of the colonization of the home planet until space-faring on a large scale became plausible?
People don't seem to think these things through when it comes to science fiction. Your basic crap, garden variety mystery novel is much more plausible than the best of science fiction, which almost inevitably relies upon notions of some kinds of technology which are magical and disdain mere laws of physics, and which imagine planetary governments, or galaxy wide confederations with a tight grip on the lives of the inhabitants of individual planets. It just ain't too bloody likely.
