Thanks to his Emmy-winning PBS children's television show, Bill Nye is the ultimate science educator to a generation of 1990s kids. His popularity has endured since Bill Nye the Science Guy ended in 1999 — including a Netflix show that returns for a second season Dec. 29 and 5.6 million Twitter followers. Yet, little is known about this beloved personality's personal life.

Nye, 62, is the subject of Bill Nye: Science Guy, an in-depth documentary that gives fans a larger sense of who Nye is as a man, as well as his motivations for being such a dogged proponent of science. Directed by David Alvarado and Jason Sussberg, the film opens in Philadelphia at the Ritz at the Bourse on Friday.

We recently spoke with Nye ahead of Science Guy's Philadelphia premiere, and got his thoughts on everything from the movie to marijuana legalization. 

Bill Nye: Science Guy gives a deeper look at your life. You’re a pretty private guy, so that must have been nerve-wracking. 

Absolutely. I'm no Kardashian. There's a part in the middle where I want to kill myself, because I signed a deal where I had no creative control.

What made you want to open up on this project?

Do you know who James Randi is? He is the Amazing Randi, a magician who offers a million dollars if you can produce a paranormal effect that he cannot reproduce. No one has ever won the million dollars. I saw a movie about Randi called An Honest Liar, which came out a few years ago. There's a part where he gets choked up and goes, "You better not put this in the film!" And that's the most telling part. I realized that if it's going to be successful, you've got to give them access.

What do you hope people take away from the film? 

That science is the best idea people have ever had, and my concern about climate change is very real, and we should all be concerned about it. We should all be optimistic and work together to change the course of human history for the betterment of all humankind. Is that bad?

That’s noble. Science denial, however, is a big part of the movie. 

The fossil fuel industry has been successful in introducing the idea that scientific uncertainty about climate change shouldn't be expressed as plus or minus 2 percent.

Will there be big fires in California? Yeah, someday — 98 percent chance. They say, "You mean there's a 2 percent chance there won't be? That's the same as 100 percent." No, it isn't, but the fossil fuel industry has been very successful. They hired some of the same guys who worked on cigarettes to introduce the idea that it wasn't completely proven that cigarettes cause cancer.

Has the Trump administration influenced the science denial sentiment in America?

I think [Trump] is a product of [science denial], not the other way around. Science denial had gone full steam before the last presidential election. Our critical thinking skills are so limited. People didn't question that Hillary Clinton may have been running a child pornography ring from a pizza place in Washington, D.C. People clicked on that and kept clicking.

So we’re screwed, basically. 

I think the pendulum is going to swing back. Here's why: the economy. What keeps the U.S. in the game is innovation — innovation in computers and phone technology, but also in agriculture. Innovation in everything. Without a better investment in basic research, you're not going to get new technologies, and you're not going to get innovation.

I think investment in all that is going to rekindle. The sooner it does, the sooner things turn around, which I think they will. But I'm of an age where I remember when Nixon resigned over what looked to be far less serious interactions. Can I say "interactions" on a phone call?

Do you consider what you do activism?

It's activism for science. As I say all the time, science is inherently political — we just don't want it to be partisan. What we decide to invest in in a society — should we send a space craft to Saturn? That's a political decision on some level. You're deciding where to apply your intellect and treasure. But that's not a red state, blue state thing.

There's a hexagonal storm on the north pole of Saturn, a geometric shape. Do you know why there's a hexagon there?

No, I don’t.

Nobody knows why! The investigation of that will lead to discoveries, and — I guarantee you — a better understanding of weather and climate on Earth. And you wouldn't even ask the question if you weren't exploring.

Sometimes people can explore too much, though, as with the recent crop of conspiracy theories, like flat Earth, going mainstream. How do you explain those ideas’ gaining traction?

Flat Earth is weird. There are clearly people who have not paid attention to anything. But the thing about a conspiracy theory that's so appealing is, it's a shortcut. If only there were 60 people running everything, we could round up those people and tell them to cut it out, and the world would just be great. It's 7.5 billion people all trying to make a living, that's how we all ended up here. It's no conspiracy.

Speaking of flat Earth, you’re going to focus on marijuana for an episode of Netflix’s Bill Nye Saves the World in the upcoming season.

The first episode's about marijuana. Turn it up loud! We wanted to call it "Episode 420," but not everyone would get it.

How did you approach investigating cannabis?

Marijuana is a Schedule I drug. That means it is presumed to be addictive and have no medical value. But many people use marijuana for medicine. Should they? No one knows, and if someone tells you they know — whether it's a politician or a physician — they don't. Marijuana hasn't been studied well enough to know. That's the premise of the show.

Those are some pretty strong words, Science Guy. Do you partake?

Speaking for myself personally, I don't smoke marijuana. It's not my thang. I smoked it once in college, but I'm just not a good smoker. I never learned to inhale very well. I didn't get high. But bear in mind that while the show is an extension of the host, I did my best to look at it objectively. A lot of people really enjoy marijuana, and a lot of people use it for all kinds of medicinal reasons.

After investigating, do you think marijuana should be legalized?

Yes. I think it has to be regulated. They say that I have DDT, an insecticide that is considered carcinogenic, in my system because when I was a kid, they sprayed DDT on everything to suppress mosquitoes. Is that bad, or is it just a thing? I don't know, man.