>#4 is ultimately at least partially a failure -- an admission of defeat on planet Earth. You assume that we give up on Earth if we ever leave for another planet? I see that as one of the biggest successes of our species should we accomplish it. Becoming an interstellar species would be a huge achievement. But I don't see why the critics of this always have to make it one or the other... why can't we take care of Earth AND travel the stars? Traveling the stars and establishing off world colonies could be the very human event that brings us all together and makes things better down here. Just look at the moon landings. Imagine a group of people from different nations starting a colony on Mars, or on a planet orbiting another star. That could be the inspirational and binding event for our species that would lead to many other better changes even down here on Earth. Perhaps you've already seen this, but it's The Sagan Series, a fan made series of videos pieced together by a fan. He explains a similar sentiment far better than I ever could.