Sean Murray, one of the creators of the computer game No Man's Sky, can't guarantee that the virtual universe he is building is infinite, but he's certain that, if it isn't, nobody will ever find out. "If you were to visit one virtual planet every second," he says, "then our own sun will have died before you'd have seen them all."

No Man's Sky is a video game quite unlike any other. Developed for Sony's PlayStation 4 by an improbably small team (the original four-person crew has grown only to 10 in recent months) at Hello Games, an independent studio in the south of England, it's a game that presents a traversable universe in which every rock, flower, tree, creature, and planet has been "procedurally generated" to create a vast and diverse play area.