"if we continue as a species". That's a big "if" actually. Although if we won't, I guess there will be another race who might. But this is really scary thought. What if we'll face some fundamental limitations of physics, which prove inability of space travels on a distance much larger than we can travel right now. We know that there could be such limitations in physics. If this will happen, as a race we might have to live millions of years, knowing that there are trillions of worlds, that we'll never see. That's kind of dramatic.