★★★ (3 out of 4)
Since Ridley Scott’s 1979 sci-fi epic “Alien” is an acknowledged masterpiece, you might worry about this eight-part prequel to the blockbuster epic, which debuted its first two episodes on Tuesday on FX on Hulu. Drop the anxiety. “Alien Earth,” from showrunner Noah Hawley (“Fargo,” “Legion”) is a massive achievement with a visual scope to match its intellectual reach.