I imagine that to travel across galaxies, we wouldn't travel in a linear fashion, the way that we do in a car. Instead, we would teleport. Of course, we would have to find out how to teleport. I also liked the imagined theory of bending time and space, the way it was described in "A Wrinkle in Time." I know that was a fictional book, but alot of what was considered science fiction in the past is now a reality today.