Early in Sunshine, a scientist on board a ship headed for the sun sits in his cabin, basking in the glow of sunlight. The sun is close enough to make out its shape and the texture of its surface, but not so close that the pure brightness of it overwhelms the senses. The scientist sits in justifiable awe for a moment, and then asks the ship’s computer what percentage of the sun’s full power he’s seeing.

“Two percent,” it tells him. It then tells him that showing just 3.4% of the sun’s power at this range would permanently blind him.

The scientist, caught in something like religious fervor, slips on a pair of sunglasses and asks to be hit with 3.1%. Just for thirty seconds. The white light surrounds him, burns him, cleanses him—as the character more or less says later, the sun’s light and power envelopes him. It’s simply that overwhelming, and the awe transfers to us: It’s one brief glimpse of the sheer power and scale of the universe we inhabit. The scientist can be nothing but humbled. This is Sunshine in its best moments.

Further humbled is the scientist’s mission: He and his crewmates are flying a massive shielded ship toward the sun to fire a bomb into the heart of it. The sun is dying and Earth is freezing over, and it’s the dim, distant hope of the crew that their bomb will rejuvenate the sun anew. That their ship is named the Icarus II indicates they are not the first crew to attempt the mission. The first crew and ship, we find out, simply disappeared.

When we come to them, the crew has been in space for 16 months. They’re fast approaching their target, and stress levels are running high. Some are more obviously stressed than others: bomb designer Capa (Cilliam Murphy) and pilot Mace (Chris Evans) often come to blows, while Searle (Cliff Curtis), ostensibly the ship’s psych officer, spends more and more time staring at the sun. One minor course-correction—and one chilling beacon from the dim hulk of the Icarus I—topples the fragile house of cards. Docking with the Icarus I only makes it worse.

Sunshine is the second collaboration between director Danny Boyle and writer Alex Garland, third if you count The Beach, based on the Garland novel of the same name and adapted for the screen by John Hodge. The other is 28 Days Later, a zombie film with ambitions to be more than just a zombie film. 28 Days Later was a flawed but worthy production, and its final act was like a compression of George Romero’s Day of the Dead. But its well-rendered characters and willingness to treat the subject matter seriously carried it into the halls of semi-cult classic status.

Sunshine has some of the same problems in its third act. Suspense and mortal peril (the kind created by human hands) makes an appearance, and though this touch is thematically sound it can’t help but feel like a substantial gear-shift from the previous hour. Sunshine is also ambiguous in many scenes, sometimes to great effect but often simply due to confusing editing. I’ve seen a hell of a lot of movies from a hell of a lot of countries, eras, and filmmaking schools, and yet more than one sequence left me completely baffled.

Less clear, too, is the film’s message. The crew of the Icarus II is quite literally trying to save their world from a catastrophe that, for once, was not caused by human hubris. But something like a debate rages through much of the film’s final moments: Is trying to literally restart the sun—an action so outsized in scope it seems absurd on the face of it—ultimate hubris or desperate courage? No, not every science fiction film needs to have a message at its heart… but Boyle and Garland always put theirs front and center. The results are, as with much of the movie, ambiguous.

But it is a beautiful film, beautiful enough that I was kicking myself for not seeing it on the big screen. A big HDTV with ambient lighting helps, but it was, to paraphrase the great sage, the difference between a lightning bug and a lightning bolt. Sunshine is a movie that instills in you a sense of the vastness, the stillness, and (yes) majesty of space. It is powerful in unexpected ways, surprising in others. Sunshine is no perfect movie, but it’s not time wasted.