Walmart Security said:
It'd be nearly impossible for us (humans) to travel throughout the whole universe, there isnt a ship big enough or enough fuel to do that.
The problem isn't exactly having a large enough ship, or enough fuel, but the incredible distances. (I don't mean to pick on you Walmart, but I wanted to clear this idea up, as I've heard it before. =P) The only time a significant amount of fuel is required is when the ship fights against a planet's atmosphere on launch (and possibly a good amount on landing, depending on the method of landing). Navigation through space itself takes very little fuel, only to rotate the ship to follow the flight path; an object moving on a straight course in space, baring any gravitational interaction, will continue to do so indefinately, in theory. Actually, a few of our early probes (Voyager, Pioneer) are coming upon their exit of our solar system. Voyager 1, launched in 1977, is the most distant human-made object in the Universe, at 8.7 billion miles from the Sun.
Getting back on track, that leads to the real problem. Distance and time. The size of the Universe is seemingly infathomable. It's so large, we don't even know if it's infinate or not. (I personally don't believe it is, but if it isn't, is it a sphere? Does it "wrap around" itself like a good ol' 2D sidescroller? I couldn't give a good answer.) Voyager 1 was launched 28 years ago, and is just
now leaving our solar system. Your lifespan would expire millions of times over on a trip to a neighboring galaxy. There's a large variety of solutions to that problem, such as cryogenic freezing, biodome-type ships able to sustain entire communities for an indefinate period of time, instantaeous teleportation (wormholes, etc), and many others.
So, therein lies the problem. Thinking mathematically, there almost
have to be other intelligent civilizations out there. The problem is, given our lifetimes and methods of travel and communication, will we ever meet them?
Carl Sagan said:
If we are alone in the Universe, it sure seems like an awful waste of space.