New Atlantist: We used to look up in the sky and wonder at our place in the stars,' Matthew McConaughey's character says near the beginning of the 2014 movie Interstellar. "Now we just look down and worry about our place in the dirt.' The filmmakers surely must have intended that remark to serve as a comment on real-life America's diminished appetite for manned space exploration. But there is another reason we no longer marvel at the sky above us as we once did, and it has little to do with withered ambition: the...