91av

• War in heaven. Titan is a moon of Saturn (7 May, p 31).

• Not that axis of evil: the is a project (30 April, p 30).

• , who suggested throwing AIs at role-playing games, is at the California Polytechnic State University in San Luis Obispo (19 March, p 5).

• The acidity of seawater fell by the desired amount when adding olivine: the pH rose (14 May, p 10).