Everybody in “Interstellar” keeps talking about Gargantua, a massive black hole that must be delicately negotiated during space travel. Christopher Nolan’s movie is similarly scaled: This 168-minute epic contains vast sights and wild images, and exerts a heavy gravitational pull.

At its center are some basic, reliable sci-fi ideas. They’re just intriguing enough to justify the film’s poky sequences, but in Nolan’s universe this one falls shy of the ingenious spectacle of “The Dark Knight” and “Inception.”

The very slow opening reels introduce us to Coop (Matthew McConaughey), a former astronaut now involved in Earth’s last-ditch effort to grow crops. The future is starving to death, but Coop has a shot at saving the day when he’s called back into astro-service for a do-or-die mission.

NASA honcho Professor Brand (Michael Caine) sends Coop toward a wormhole, the better to galaxy-leap and find the remnants of previous explorers who searched for a new home for humanity. The crew includes Brand’s daughter (Anne Hathaway), two specialists (Wes Bentley, David Gyasi), and a cool mobile computer (nicely voiced by Bill Irwin).

Once in space, the mission offers good science fiction stuff. The most tantalizing idea is how space travel alters the way time passes — so the longer the astronauts linger near Gargantua, the more McConaughey’s kids back home will surpass their father in age. Relativity can be harsh.

Jessica Chastain and Casey Affleck play the grown-up Cooper children. Except for McConaughey’s straight-up emotionalism, none of the characters is especially vivid. Nolan seems bored by many of the Earth scenes, as though he can’t wait to expose the quantum physics that lurks in the walls of an ordinary farmhouse. (Late in the movie, he will.)

I enjoyed the science talk, and the worlds we visit are cool — there’s a watery planet with mountain-sized waves, and a frozen planet where the travelers meet a very relieved survivor of a previous mission (this is one of the movie’s best sustained episodes). Nolan aims big with these things, and there are some bulls’-eyes.

I saw the film at an IMAX preview, which is a sensory-overload experience. Some of those big-format visions are impressive, although the non-IMAX scenes (shot on film, not digital) look drab by comparison.

People are already comparing “Interstellar” to Stanley Kubrick’s “2001: A Space Odyssey,” because both films tackle large ideas in space. This does “Interstellar” no favors. “2001” makes us ponder the nature of existence by declining to explain its enigma; “Interstellar” explains like nobody’s business, and settles on answers — intergalactic love vibes, for instance — that Kubrick would have blanched at.

Nothing is left unstated in this journey, which may be why the movie doesn’t have that glorious sense of mystery that great sci-fi films leave behind. Still, its reach for the stars is often exciting, and as utter spectacle it delivers a rare sense of the colossal.

“Interstellar” (3 stars)

Matthew McConaughey journeys into space to save the human race, a trip full of director Christopher Nolan’s big-scale visions. The movie’s got its poky sequences and a tendency to explain away its mysteries, but whenever it’s in flight it conjures up a real sense of the colossal. With Anne Hathaway, Jessica Chastain.

Rating: PG-13, for language, subject matter

Showing: Alderwood Mall, Cinebarre Mountlake Terrace, Everett Stadium, Galaxy Monroe, Marysville, Stanwood Cinemas, Meridian, Thornton Place Stadium 14 + Imax, Varsity, Woodinville, Cascade Mall, Oak Harbor Plaza.