Sandra Bullock and George Clooney star in the 3D space odyssey that drew loud applause after a tight 90 minutes. It now has folks tossing around words like “astonishing” and “brilliant.” The tense sci-fi actioner sees Bullock and Clooney stranded adrift after debris hits their space shuttle. (Bullock also has a lot of alone screen time.) Cuaron, who makes use of his taste for long tracking shots, is being largely praised here in Venice with some now even wondering why the film wasn’t in competition. Cuaron has won prizes in Venice before, for 2001′s Y Tu Mama Tambien and for 2006′s Children Of Men. Gravity, co-written by Cuaron and son Jonas, officially opens the festival tonight with director and stars in tow.