For the past few years, at happy hours and dinner parties in San Francisco, Leopold Aschenbrenner kept confusing people by sharing his favorite outlandish idea.  He wanted to buy galaxies. Some of his friends weren’t always sure what to make of Aschenbrenner’s intergalactic ambitions. He once left the room and they debated whether he was referring to physical galaxies or a type of private plane.  No, he assured them when he came back. He meant galaxies.  His idea was that advances in artificial intelligence would soon unlock resources on a cosmic scale, enabling humans to colonize faraway planets. He planned…