The world’s richest man now has the keys to one of the most influential social-media platforms. Can it be the free-speech wonderland he is aiming for? Should it? In America marriages involving those under the age of consent remain surprisingly common; we examine why reform remains distant. And a look at the push to redesign outdated, clunky spacesuits. For full access to print, digital and audio editions of The Economist, subscribe here www.economist.com/intelligenceoffer