Out of This World. Music from ''2001: A Space Odyssey;'' ''Alien''; ''BattlestarGalactica''; ''Return of the Jedi''; ''E.T.''; ''Star Trek''; ''Twilight Zone.'' The Boston Pops, John Williams, conductor (Philips digital 411 185-1). - I suppose one could call this album predictable, but what glorious predictability. Williams's Boston Pops orchestra is superbly recorded, and he gets it to play with a fervor he cannot get out of the studio orchestras he works with for his sound-track albums. And to find such items as Jerry Goldsmith's ''Alien'' represented - if only three minutes' worth, and it's such a good score - and Marius Constant's ''Twilight Zone'' theme and variations (in a fine symphonic presentation) is welcome. The only trite moment is in the ''Star Trek'' TV show theme - a sample of the old-Pops-style arrangement that sounds out of place on this disc. Otherwise, Mr. Williams has given this music concert hall status, as it richly deserves. Bravo, and more please!