Nick Zentena wrote: > > On June 1, 2003 10:27 am, Steve Desjardins wrote: > > Sci. Am had a special section on this a while back. (July 2000) My > > favorite arguemnt involves assuming that a tehcnoogocial species arises, > > sends one colony ship out at 0.1 c, it takes 400 years for that colonoy > > to send out another ship, etc. Making these estimates, the entire > > galaxy should be colonized in about 5 million years, whihc is a blink of > > the eye in cosmic terms. So where are they?
Merely mathematically speaking, that's only 12,500 forays into the reaches of the galaxy. Way too easy to get lost, or from their viewpoint, way to easy to miss such a miniscule number of visitors! What is YOUR definition of "colonizing the galaxy?" Maybe I missed something. Dump a thousand tons of sand into the ocean. Once the murkiness disappears, where's your sand? Even bright flourescent orange sand, what are the chances for your ever finding such a grain? Seems to me it would take a LOT more than a 5 million year period. > > You then get into "intelligent but no tech", deliberately avoiding us, > > etc. A good read if you like this stuff. I guess I'll have to visit our local library to see if I can take out a copy... > My feeling is when the next door neigbour is 4+ light years away you're > aren't going for a cup of sugar. At 1/10 of light it's 40+ years each > way. Ignoring speeding up and slowing down. That's next door. > > Now lets say they have come. Say 100 years ago a ship showed up. Took out > there disposable camera. Took pictures of all the tourists things. Left some > graffiti on a wall. Ticked Earth off the list of things to do before they > die. Are we ever going to know they've been here? No. I am of the opinion it's happened before. and other than some inexplicable oddities here and there, which we've become used to "observing" but remaining ignorant of any significance, we go our way as tho' nothing happened. Of course we wouldn't know of it. keith > Nick
