"IT WILL BE DIFFICULT ENOUGH to avoid disaster in the next hundred years, let alone the next thousand or million," Stephen Hawking said in 2010. "Our only chance of long-term survival is not to remain inward-looking on planet Earth, but to spread out into space."

Easier said than done—especially given NASA's ever-shrinking budget and the fact that America, whose space program was once one of its proudest endeavors, has largely shrugged off its token stabs at space exploration to private enterprise. It isn't a particularly bright time for it, either: Last week, Virgin Galactic's manned SpaceShipTwo, intended to shuttle rich tourists on brief visits to Earth's upper atmosphere, crashed in the Mojave Desert; a few days earlier, an unmanned Antares rocket, owned by the Orbital Sciences Corporation and carrying equipment for the International Space Station, exploded just after liftoff.

At least we're not in as dire of a spot as the people in the near future of Christopher Nolan's Interstellar, where climate change has turned much of Earth into a poisonous dust bowl. It's a distressingly plausible end-point to our current environmental circumstances: Earth in Interstellar is a sun-baked dystopia where humanity scratches meager survival from increasingly barren soil, and where the financial, physical, and emotional challenges of daily life have relegated space travel to a half-forgotten past.

That changes when Cooper (Matthew McConaughey)—a pilot turned farmer, caring for his daughter Murph (Mackenzie Foy) and his son Tom (Timothée Chalamet)—is given the chance to lead a last-ditch effort to find a new home for humanity. He takes it, leaving behind his family and his planet to undertake a brutally uncertain expedition.

To say more about the journey of Cooper and his small team of astronauts—Amelia (Anne Hathaway), Doyle (Wes Bentley), Romilly (David Gyasi), and two friendly robots (!)—would kneecap the film's eye-widening moments of fear, excitement, sadness, surprise, and above all else, discovery. Interstellar (like Kubrick's 2001: A Space Odyssey, to which it owes a huge debt) is a film best gone into with little preparation, and (like Alfonso Cuarón's Gravity, with which it shares a few themes) it's also a beautiful, visceral display that you can't really claim to have seen unless you've seen it on the big screen.

Unlike most of Nolan's other recent pictures, though—which always succeed when it comes to bombast, but whose rickety narratives rarely hold up—Interstellar's story is earnest and complete. Even as Nolan (who co-wrote the film with his brother, Jonathan, following a concept from theoretical physicist Kip Thorne) veers from hard science to metaphysics, orbiting places and plot threads the previews have avoided even hinting at, all of Interstellar's far-ranging elements feel of a piece. "Feel" might be the operative word here, actually: This is the kind of intensely big-hearted science-fiction that cares as much about its characters as its wormholes; as with other speculative films this bold, like Robert Zemeckis' Contact or Spielberg's A.I., not every beat works, but it's a cold-hearted bastard who'd begrudge Nolan's ambition.

Which is what Interstellar's about, really: reaching. There are big, blockbuster moments here, with glorious, overwhelming spacescapes, a thudding Hans Zimmer score, and three hours of steadily increasing peril. But far more than most blockbusters, Interstellar has something to say. Beneath its spectacle, it's a film about how if we want to evolve, we first must explore. That's something we could all stand to hear. It's been 42 years since we went to the Moon.