Leave it to someone as ambitious as Sufjan Stevens—who once pledged to write an album for every U.S. state—to help dream up a song cycle about the cosmos. Starting life as a commissioned work by the composer Nico Muhly, Planetarium pairs Muhly and Stevens with National guitarist Bryce Dessner and percussionist James McAllister for a restless, eclectic set that weaves from Auto-Tuned R&B and trombone chorales (“Mars”) to sparkling washes of ambience (“In the Beginning”) and wide-eyed EDM (“Saturn”). It’s an indie-world take on the wonders of '70s prog.