You can't travel faster than the speed of light, thats why scientists in a few years will raise the speed of light.
-- end futurama joke.
I think anything is possible. This is going to sound stupid and I am 100% sure some people will disagree with this, but if you look at some of the things we take for granted now, and what we had just 10 years ago, it is impressive.
When I was on a 40mb, 286, monochrome, brick of a laptop with no network/internet,(maybe more than 10 years!) I never thought we could get graphics cards with 100x the power of the laptop itself, dual core cpus (with quad and more coming probably before the end of 06), internet, and more.
I never thought that I could hold a mobile phone in my hand, and have a video chat with someone who is far away.
I never thought a lot of things would be possible!
a few years ago, I would not beleive that in a car, I could have a GPS system that can tell me exactly where to go by voice and 3d maps (maybe more than a few years ago!)
When it comes down to it, science is only true untill someone says it doesnt make sense anymore, If you look in history, like the Romans, they were sure they knew how the human body worked, they were sure they knew everything, and it was reguarded as the truth, and barely anyone questioned it. Doctors, scientists, and everyone else believed what they were doing as much as we believe in what we are doing now.
fine, it was wrong, and now we actually have to do a higher level of proof to any claim, and a lot of things have changed, but what I am trying to say is that they believed so much in everything they did, as much as we all believe in our rules today.
I am not saying things like faster than light travel will be here tommorow, or in the next 50 years, but who says what the next 1000 years will bring... we have come a long way, and I believe we have much further to go.
I saw on a program Nasa are trying to make a family plane that is self guiding, and could be used to replace cars in the next 10 years... I think more like 50 years, but still.
sci fi is becoming ever so more real, I never thought that holograms could become real,
http://www.io2technology.com/
things of fantasy that some people say are impossible, are becoming real.
there are things that will be impossible of course... but I just dont think there are too many things to rule out, as I said, not tommorow, but who knows what will happen in 100 years from now!