Imagine if we actually found life on that planet. its a destinct possibility as well because if I'm not mistaken all life starts in the ocean. that could be our first encounter with multicelular life Also would we not want to wait untill theres a planet we could visit without dying before pulling the Reach card.
or faster than light speed travel? and, assuming "space" is comprised of nothingness, you would only need one HUGE burst of energy to travel as fast as light, then a hell of alot of energy to stop.
The guy who came up with star trek has a whole theory on faster than light travel (or near too is) basically warp sapce, same concept as the halo sakawafujia drive that the ships use.