American entrepreneur Steve Kirsch has said that Elon Musk, the world's second-richest person, replied to his e-mail in less than 3 minutes. "I am convinced he's super-human...How is this humanly possible...I want to know his secret," Kirsch tweeted. "Some people speculated it is AI. No AI is THAT good. It's totally him," he clarified. Musk responded "lol" to Kirsch's tweets.