Michio Kaku believes that most intelligent societies eventually destroy themselves and it will be a miracle if we don't destroy ourselves.
unless you are moving at almost the speed of light 100 years gets you nowhere. also even if you have an extended lifespan and could travel at near lightspeed you would have to know exactly where you're going for it to be practical. at this point the signals from our species are still invisible to 99.999% of the galaxy. I don't. it is just one of many alternate hypothesis that would explain why we haven't been visited even if intelligent life happened to be common. you implied that there is some significance to the fact that we haven't been visited. there is not. there MAY be some minor significance to the fact that we haven't detected radio signals from other life, but we haven't really put a lot of comprehensive effort into searching so far (which is fine with Denny )
Well, assuming other planets are made from the same stuff our planet is made from and their resources are finite, much like our own, it's most likely that they are in the same boat as us -- doomed to die alone. Maybe we're in the backwoods, though, and there are solar systems with two or three inhabited planets. But the sheer distance is just insane, and the technology required is beyond imagination.
Derp. Okay well, I will backtrack and say that it is possible that intelligent life somewhere could come up with a way for interstellar space travel. But it won't be us.
We can only guess. Mine would be that we will be able to travel vast distances. Star Trek tech is going to be a reality. Warp Drive - a warp bubble something like this: http://en.wikipedia.org/wiki/Alcubierre_drive And it'll require antimatter type energy (mass quantities) to work.
