According to recent simulations, the idea of making a life for yourself on a planet closer to the center of the galaxy has hit a natural barrier as well as a (lack-of-way-to-get-there-and-survive) technological one: Too many comets.
New Scientist reports that Italian researcher Marco Masi has discovered that the stars and gas clouds at the center of the galaxy are so tightly packed that twice as many comets are shaken loose, and could hit planets at twice the impact of similar Earthbound objects. Which would mean that some kind of force shield that would protect future space colonies from collisions might be the first thing to add to any future to-do list, really.
Life in the inner galaxy would be bombarded by comets [New Scientist]
