John Powers reviews Nostalgia for the Light, Patricio Guzman’s tribute to the Atacama Desert — the driest place on Earth, and home to both sophisticated observatories and the sober memories of a military regime’s abuses:  ”Watching Nostalgia for the Light, I suddenly remembered visiting the memorial to the Jewish heroes who fought the Nazis in the Warsaw Ghetto. I was surrounded by an Israeli school group, whose teachers, moved to tears by what struck them as sacred ground, were aghast to see their students giggling, horsing around and flirting — in short, being teenagers. And though my brain sympathized with the adults who honored the memory of those blood-stained cobblestones, my body was on the side of the kids, who were living, breathing, exuberant proof that life goes on.”