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General Discussion / Re: Stephen Hawking is afraid of aliens
« on: May 06, 2010, 11:32:40 pm »It's a tossup. They might be quite close, depending on how common life is. http://www.solstation.com/stars3/100-ks.htm and http://www.solstation.com/stars3/100-gs.htm is one reference, for G and K type stars. Obviously the number in range is going to increase non-linearly - you won't find 1500 more by going out 200 light years, rather quite a bit more. 200 LY is not an impossible distance at sub-light speeds, especially not relativistic speeds relatively easily achievable with an unmanned device. If they were at exactly 200 ly, and were actively looking for radio waves with large telescopes and without much interference from their own technology (something we can assume given they are at a stage that requires long-range communications, since we haven't heard anything out there yet), we'd still have well over 300 years to prepare for an automated attack. But the way things are going now I don't think we'd be prepared, even given that time span... Eh, who knows really?This is assuming they do have FTL. That their technology isn't more like how science will realistically go without it - higher and higher speed computation, towards digitization of intelligence, or at least very powerful research and engineering tools. Realistically, interstellar distances are the exact opposite of what you need to build better computers. That means they might not have bothered to establish a foothold on other planets, and even if they have, they might be more vulnerable than we are to sudden attack, or at least more cautious with better tools to exercise that caution.
We aren't afraid of swords and plate-mail anymore. We have guns. Does that mean we'll let someone walk around in the city threatening people at sword-point? No. We detain them, kill them if we have good reason to believe they are about to kill someone else. Same, I think, with us. Our best bet is to step carefully. Unfortunately that will never happen.
If they don't have FTL, the chances of them finding us are pretty much nonexistant.
Seriously, space is just that big. Without FTL it's just flat out not feasible to travel beyond your star system and any immediate neighbours.
Oh i'm not saying it would be infeasible to find other aliens nearby, just that it would be infeasible to actually do anything to them.
To take your 200 LY example, that means that even at light speed, it's going to take at least 200 years to get from there to here. There is no way in hell you can manage any sort of invasion or anything with a 200 year travel time.
The old Medieval kingdoms managed with a few years travel time, and i'd say anything out to ~10 light years would be doable, but difficult. Anything further than that isn't though, especially since in order to go much further than that you're going to need 'generation' ships, which are never going to work.
And just what do you think we can do against orbital bombardment? If they blow up a couple of major cities, we're going to be crawling into their asses so deep you won't see our shoelaces, just if they promise to stop killing us.
We can already send nuclear missiles into space you know. If they're in orbit, they're in range.
