Christopher Nolan is a latter-day master of the head-trip blockbuster. But Interstellar, his latest (and, at nearly three hours, longest) film, is oddly earthbound, writes Kurt Loder. Especially for its first half hour, in which we see that our planet has been reduced to a parched and choking dustbowl, the movie is burdened by the exigencies of plot-setup. And even later, when it breaks free into outer space (and some glorious visual effects), its dialogue and characters keep pulling us Earthward. The picture is ambitiously brainy and technically meticulous; but like Nolan's earlier Inception, it leaves us (well, some of us) wondering if all the mind-knotting complexities really add up.