Andrew Ng helped create two of Silicon Valley's leading artificial intelligence labs. First, he built Google Brain, now the hub of AI research inside the internet giant. Then he built a lab in the Valley for Baidu, the company known as the Google of China. Ng was one of the primary figures behind the enormous and rapid rise of AI over the last five years as everyone from Facebook to Microsoft rebuilt themselves around deep learning. And on Tuesday night, he announced his departure from Baidu.