Scientist Stephen Hawking -- one of the most brilliant minds in history -- has died at the age of 76.

Probably the most famous scientist of his time, Hawking was popular across the globe. When he joined the Chinese microblog Weibo two years ago, he quickly amassed a million followers within a day.

Blogging in English, the renowned astrophysicist occasionally answered questions from enthusiastic users, including one from a Chinese pop star asking how humans should prepare for interstellar migration.

Responding to another question about the reality of our existence, Hawking wrote, “How do we know if we are living in our dreams or reality -- well, we just don’t and perhaps can’t!”

In recent years, Hawking was among the leading voices warning about the danger of artificial intelligence.

It’s a particularly potent and timely message to China, which is aiming to become a global leader in AI. Speaking to thousands of tech workers in Beijing on video last year, Hawking said true AI can be either the best or the worst thing ever to happen to humanity.

“I believe there is no real difference between what can be achieved by a biological brain and what can be achieved by a computer,” he said. “Humans, who are limited by slow biological evolution, couldn’t compete and could be superseded by AI.”

On Wednesday, news of Stephen Hawking’s death was the top trending topic on Weibo.

One user wrote, “Stephen Hawking has returned home -- to the universe where he belongs to.”