Another Earth (2011)

Equal parts astronomy and philosophy, Another Earth is — like 2004's Primer — a Sundance darling that does smart sci-fi on the cheap. The discovery of another planet identical to ours serves as the backdrop to the story of a young woman (Brit Marling) who accidentally kills a family while driving drunk. Director Mike Cahill says the film's modest budget was a virtue, allowing him to focus on the story's character-based sensibilities. ''If we had a huge budget, we might have been tempted to have rocket ships nuking Earth 2,'' says Cahill. ''Or explosions and Will Smith in a cowboy hat and cigar rescuing everybody.'' Save that for the sequel. —Keith Staskiewicz