BEVERLY HILLS, CALIF. — As Christopher Nolan’s long-anticipated outer space adventure “Interstellar” opened Wednesday — given a rave four-star review by Sun-Times movie columnist Richard Roeper — one of the movie’s stars, Anne Hathaway, admitted to me she had trouble getting her head around the astronaut role she plays.

“My character, Emilia Brand, she really perplexed me at first,” said the Oscar winner. “Usually when I read a script I get a strong sense of how to play a character. It’s almost a little bit mystical, like it’s this other energy that I tap into. With Emilia, she had so many layers, so many secrets, so many parts to her — I didn’t understand how they all fit together.”

Then Hathaway thought about some of the really smart people she has met over the years. “I remembered how when you first meet them, they can be a little socially awkward. Then as you get to know them they warm up and relax.

“So, when I figured out that aspect of her personality, the rest of it fell into place and I figured out how and why she got to be that way.”

While “Interstellar” is a big-budget film primarily geared to entertain audiences and, hopefully, wow them, Hathaway said Nolan also wanted to convey an ecological message, as the underlying theme of the movie is about a search for a new planet to support Earth’s inhabitants, who are facing the eventual collapse of the planet.

“Maybe because I played a character who spent a lifetime of NOT taking the Earth for granted, my relationship with nature in the film is different. But it also mirrors my personal feelings as well. I gravitate to nature. It makes me sound like such a hippie, but I don’t care. It makes me so happy to just sit and watch the breeze blow through the trees. I consider that to be as profound a miracle as you can imagine. The fact that it all works and we’re just sitting here, watching this thing, this Earth, exist — it really moves me,” said Hathaway.

Jessica Chastain, who plays Matthew McConaughey’s daughter Murph as an adult, was intrigued by how Nolan was able to combine a big space film with quite a few intimate moments and stories involving the primary characters.

“What I love so much about this film is it is definitely a thrilling, hold-your-breath, space adventure with the exploration of outer space and those unbelievable special-effects scenes that are happening the whole time. Yet at the core of the film, it’s about the powerful bonds of love. It’s about the relationship of a father and a daughter. It’s about the fact that love never dies,” she said.

Having made this film, Chastain said she’s now convinced human beings need to continue space exploration.

“At one point, I asked Chris [Nolan], ‘Do you think we will go back out there more aggressively and explore space further?’ He said, ‘I don’t think it’s a question of if, but when. We definitely will do that.’

“I see his point. It’s in our nature as people. We, humankind, we’re explorers. We always have been. I remember when I was young and seeing the terrible Challenger disaster. After that, I think the idea of going to space kind of disappeared from our radar.

“But how exciting it will be that there might be children who watch this movie who might then say, ‘I want to be an astronaut when I grow up!’ “