Astrophysicist-turned-TV-star Neil deGrasse Tyson with his wife at the 2014 Time 100 gala. Ben Gabbe/Getty Images for TIME Long before Neil deGrasse Tyson hosted Fox's successful documentary series "Cosmos," he was more famous for his work in the science community as a leading astrophysicist, author, and educator.

But it wasn't easy for the 55-year-old to transition from teacher to TV star.

"It was hard because as an educator and as a scientist, I give lectures and there's up to 1,000 people in the room and I see what their reaction is at every moment. Are they asleep? Are they bored? Are they excited? On TV, there's no response, no information," deGrasse Tyson told Business Insider at Tuesday's Time 100 gala, which celebrated what the magazine considers the most influential people in the world.

The astrophysicist added: "I prefer a live audience. The TV scares me a little bit, because I don't know if I'm connecting. I have to rely on my life experience having connected, to know that this is working, even though I have no data on whether or not it actually is."

"I prefer a live audience. The TV scares me a little bit, because I don't know if I'm connecting," deGrasse Tyson said of hosting Fox's "Cosmos." Patrick Eccelsine/FOX

As for why deGrasse Tyson wanted to resurrect "Cosmos" — nearly 35 years after Carl Sagan hosted the original show — he said, "I thought 'Cosmos' needed to be done again and I thought I could do it and do it well. Forces came together with the original writers of the series and so the rest came together."

But first, the scientist needed TV training.

"I have no experience reading from a teleprompter — none!" he said. "So I needed some training to read from a prompter in a way that's just natural. I think I pretty much succeeded. I can talk about the universe like I can talk about my living room — couch is here, TV is there, solar system there — but TV was more of a challenge."

With a show on a major network came a new level of fame.

"I was pretty public before then so it's really just an increment," the married father of two said. "It went from, like, 50 people a day to 200 people a day who would stop me in the street. But once I passed 10 a day, I knew that my privacy was gone."

Not that he minds. "It comes with what I've been doing, so it just is," he said. "Now I have to just be a little more groomed when I leave in the morning. You can't scratch yourself or do things that you may otherwise want to do, but I've grown accustomed to it."

But deGrasse Tyson said that, luckily, his fans aren't like the paparazzi:

"It's not people who ask me my favorite color or anything. Instead, they say, 'Thanks for teaching me about black holes and the universe.' To an educator, that's a special comment."