When interested in answering questions of plausible future technologies, we obviously can only reasonably appeal to what is known of physical law. In the not-so-distant past, the quantum computer was only a kind of mathematical abstraction, but of late developments in laboratories have been making their way into the popular science press. In the area of space exploration, the situation appears to have moved in an opposite kind of direction as assumptions that space flight could be done over long distances have run up against a harder analysis of what this really would entail. It has even become a kind of dogma that space flight is so limited theoretically that life is always essentially stuck in its neighborhood of origin. This is in contrast to prior confusion over why if life should be relatively ubiquitous, or even not so ubiquitous, we should now find ourselves with no reliable evidence that it exists anywhere other than on Earth. The presumed fact that intelligent life must almost certainly by now have had the opportunity to at least contact us from elsewhere butting up against the absence of evidence is called the Fermi Paradox, and a reasonable article on the subject can be found at wikipedia, though it doesn't handle certain things like the topic of this thread at all well. I leave the floor open for discussion with only a note that there was written last year an article dealing with a very very extreme type of plausible engineering involving the generation of artificial black holes being used, when 'tethered' to the back of a vehicle, for propulsion via Hawking radiation. The fact that such an article was written is an indication, and the authors say as much, that the options for space flight appear to be very limited. [I will provide a link to the article as soon as possible if someone else doesn't beat me to it.]

Note: Hawking radiation is a generally accepted, but still unobserved (and unobservable without small black holes), part of theoretical physics. Black holes, though commonly thought of as sinks that gobble up everything including light that comes too close, should theoretically evaporate according to a precise pace that speeds up as they get smaller. The article in question deals with the ideal size for the authors' proposal.

Before we can colonize other solar systems, we need to learn to build habitable cities that orbit the sun, not Earth. Within our own solar system, in this way, the human population could reach hundreds of trillions. Many orders of magnitude more than if we could colonize the whole surface of every planet in the solar system. Very few resources would even need to come from expensive transport from planetary surfaces, with the asteroid belts to mine.

Only then would we reasonably expect the develop the technologies for colonizing other solar systems. The sun is the primary resource, not planetary surface colonies. I can't even imagine a planetary based civilization surviving deep time. By the time such hypothetical technologies to control planetary tectonic forces, and other issues, some highly unlikely event is more likely to take them out given the time span involved. Not to mention the population limits of a planet.

We have too much to accomplish in this solar system, before worrying about colonizing other solar systems just yet.

The Fermi paradox isn't a paradox, and isn't even a real issue for those with a real understanding of the size of the cosmos, which was only just being understood in 1950, when Fermi uttered his famous question 'Where is everybody'. The problems faced in crossing large distances in space in manageable time frames are not insignificant. Even travelling at close to light speed, so that the time experienced in the inertial frame of the traveller is reasonably small, the time outside that frame is still ridiculous. For example, a round trip to Andromeda at a snip below lightspeed would take only about 50 years from the frame of the traveller, while outside that frame, 6 million years would pass.

Yes, hackenslash made a good point. Consider a civilization just half the diameter of our own galaxy away from us, about 50k light years. They can't possibly know we are technologically advanced for at least another 50,000 years. By that time we'll be 50,000 years more advanced than they can see. Neanderthals were still alive.

Same for us looking for them. If they've been developing a technological civilization the last 40,000 years, then even if we had a telescope to see insects on the surface of their planet, we wouldn't see a technological civilization for another 10,000 years. From the perspective of the nearest galaxy, sapiens is not even within a million years of forming a separate lineage from the other primates yet.

The Fermi question is less about where than when.

hackenslash wrote:For example, a round trip to Andromeda at a snip below lightspeed would take only about 50 years from the frame of the traveller, while outside that frame, 6 million years would pass.

Is it (remotely) possible that while I am rocketing up Andromeda way at close to light-speed the scientists of Earth crack the Alcubierre Metric, only for me to arrive back in my home galaxy and find it over populated?

Ironclad wrote:

hackenslash wrote:For example, a round trip to Andromeda at a snip below lightspeed would take only about 50 years from the frame of the traveller, while outside that frame, 6 million years would pass.

Is it (remotely) possible that while I am rocketing up Andromeda way at close to light-speed the scientists of Earth crack the Alcubierre Metric, only for me to arrive back in my home galaxy and find it over populated?

Yes, it's possible, even without an Alcubierre drive. I don't even personally think an Alcubierre drive is even possible, but no sense giving up trying as long as it's not demonstrated to be wrong. Yet it's not needed if the speed and departure times are right.

Well it better be something more time-economical than just going bloody fast, otherwise the galaxy will die of old age before we get anywhere.
Not that I'm in a hurry, just saying.

The OP was not about colonization or about travel to Andromeda.

Here is a brief article that links to the more technical one.
http://www.universetoday.com/45571/blac ... starships/

hackenslash wrote:The Fermi paradox isn't a paradox, and isn't even a real issue for those with a real understanding of the size of the cosmos, which was only just being understood in 1950, when Fermi uttered his famous question 'Where is everybody'. The problems faced in crossing large distances in space in manageable time frames are not insignificant. Even travelling at close to light speed, so that the time experienced in the inertial frame of the traveller is reasonably small, the time outside that frame is still ridiculous. For example, a round trip to Andromeda at a snip below lightspeed would take only about 50 years from the frame of the traveller, while outside that frame, 6 million years would pass.

I was thinking explicitly of you, hackenslash. The fact that Douglas North Adams had this "real understanding" has always been satisfactory to you. Meanwhile, numerous actual scientists, as opposed to a solitary science-fiction writer, are benighted according to your quantitatively unsupportable dogma. When I suggested (eons ago, it seems) that you read the wikipedia article on the Fermi. Paradox, your response was that you essentially know all there is to know about the subject. Now, no doubt, you can at least find a scientist who believes as you do. When you name him or her, I'll address the opposing viewpoint.

I'm perfectly happy to consider that the Fermi paradox is not really a paradox so much as an unresolved issue; but in the final analysis all mysteries involving reality-based expectations butting heads with observations that don't meet those expectations can only be put in a few categories, and the historical use of the word 'paradox' matches up well with this particular unresolved issue.

Except, of course, that observations precisely meet those expectations when your expectations are based on the very real limitations to travel across huge stretches of space in reasonably manageable timespans. Given that we have been transmitting radio signals for somewhat less than a century, and given that even our own galaxy is 100,000 lightyears across, this means that our signals have barely begun to cross the galactic disk by comparison. That being the case, your ignorant assumption that we should have detected any civilisation that was out there by now is simply asinine, and only exposes the limitation of your thinking when considering the size of the cosmos and the time it takes to get anything done in it, even at the limit of information transfer. Perhaps it's just because the sixe of the cosmos is not palindromic, and therefore not open to your fucking preposterous wibblings, that you clearly have no fucking idea of what you're talking about.

Incidentally, Douglas Adams' middle name was Noel, not fucking North.

Oh, and what precisely do you actually think there is to know about the Fermi paradox that I haven't already demonstrated my understanding of? Indeed, I have perfectly stated the Fermi paradox in the post you have quoted, in the question 'where is everybody?' which was precisely how it was formulated by Fermi. I also delivered an explanation of why it isn't a paradox, which I note I have done in the past, but that you seem to have failed to grasp. Do you really need to be educated in how long it takes for signals to cross the cosmos, given that the cosmos is somewhere between (at current estimates) 96 and 156 Gly across? That means that it takes a signal at least 96 billion years to get from one side to the other at the lower end of the estimate. I don't know how good you are at counting, but that means that it would actually take roughly 7 times the age of the universe for a signal to cross from one side to the other!

This isn't remotely an unresolved issue, except to those who can't fucking count!

Awe, did I insult the closest person to a scientist you can think of who thought this was obvious by mistaking what his middle name was?
Now, you are certainly correct if you assert that perfectly plausible explanations have been adduced to resolve the issue, but your comprehension of what these arguments are is meager, to say the least, and you're demonstrably incompetent at making a good scientific argument (and your math is weak and manners absolutely without parallel in their atrociousness).
Also note that this very post, like others before, clearly indicates that I am not making the assumption you appear to believe I am.

I couldn't give a flying fuck about your opinion of my manners, as it is of absolutely no consequence to me. The rest, you'll have to actually demonstrate, rather than simply assert.

Oh, fuck, I forgot who I was talking to.

Quote me my assertion. You mean the one stating that you haven't named a scientist? I certainly haven't forgotten you, by the way.

Assertions quoth thus:

your comprehension of what these arguments are is meager, to say the least, and you're demonstrably incompetent at making a good scientific argument

Why would I need to quote a scientist, when I am citing well-established scientific principles? Do you really need me to cite Einstein for the principles of relativity, or is it that you doubt the citation of the size of the cosmos? If you really need these principles cited, I am perfectly happy to bury you in empirical verification of the principles of relativity and the implications thereof.

Even if we were to take the size of the cosmos, for the sake of this pretty silly discussion (especially one conducted with somebody who purports himself to be a mathematical genius, such as yourself), as only being that which we can observe, namely 27.4 Gly across, that would still require that a radio signal that left the outer edge of the observable cosmos would have to have originated at the big bang for us to detect it. This is further based on the assumption that we are actually employing the means of communication that our hypothetical signallers were using.

This isn't scientific argument, but empirical fact, which your palindromic fucknuttery seems ill-equipped to deal with.

Perhaps if you stopped looking for connections between arbitrary values, you might actually learn something about reality.

Well, on the basic subject of this thread of whether or not the limitations to reasonable-time-period interstellar space travel is possible, I'm sure we can agree that first one has to expand upon what is meant by a reasonable time period and then one has to address the engineering. Other questions are a side-show that may have some little purpose (Things like the size of the entire universe are totally irrelevant and only highlight that you are grasping at straws and bad at it), but they aren't what was intended clearly in the OP.

So, no actual support for your assertions, then? As I thought, the usual guff we've come to expect from you.

hackenslash wrote:Assertions quoth thus:

your comprehension of what these arguments are is meager, to say the least, and you're demonstrably incompetent at making a good scientific argument

My previous post tackles this choice of assertion directly in the parenthetical, but you say 'assertions', plural. What else?

Okay, a more broadly encompassing perspective people may wish to discuss is at http://en.wikipedia.org/wiki/Interstellar_travel . It includes some bizarre-sounding sub-topics, but it also points to at least one other propulsion scheme that doesn't involve physics not yet known and doesn't seem to have been ruled out as infeasible. I'm satisfied that I know what I want to about the subject right now from my reading of it.