Actually, in space, someone can hear you scream.

And now they’re here.

They’re the alien invaders of “A Quiet Place,” giant insect predators that hunt by sound. Ferocious and voracious, they’ve already eaten most of our planet, city by city. And now they’re in your little town. Better hold your breath.

It could be your last.

That’s the idea behind this great scary movie from real-life couple John Krasinski and Emily Blunt. They co-star as a couple of New York farmers, with three cute kids, a nice spread upstate — and a horde of hungry, grasshopper-like things trying to get into their house.

The busy Krasinski also directed, and helped produce and script. He has created a smart, surprising little shocker. Because sound has become the most dangerous thing on earth, the family stays as silent as it can. So does the film, giving it a fresh, unearthly feel.

Mom and Dad and the kids mostly talk in sign language. (One of their children is played by the hearing-impaired young actress Millicent Simmonds.) Music and sound effects are kept to a minimum. Wordless seconds turn into almost unbearable minutes.

The actors, though, don’t need dialogue to build characters.

Krasinski brings his own quiet, small-town decency to the hero. Blunt gives her farm wife plenty of old-fashioned, pioneer-woman pluck. The deserted small-town locations are genuinely spooky, too, and there are a couple of shocking action sequences.

In one, the pregnant heroine, alone on the farm, suddenly goes into labor — knowing that even a small gasp of pain may bring on the predators. In another, a child falls into a silo, corn kernels sucking him down like quicksand — giving new meaning to the phrase “popcorn movie.”

What’s most shocking about those scenes is the movie’s own unsentimental realism. This may be a sci-fi fantasy about giant man-eating bugs, but it’s grounded in human facts and folly. Little here is safe. Nothing is predictable.

It’s surprising how effectively the silence increases the scares, too. We’re used to directors who can’t dial up the tension simply pumping up the volume, adding shrieks and screechy music. They trade horror for headaches, monsters for migraines.

“A Quiet Place,” though, cleverly reminds us of just how unearthly nothing can be. You sit and watch, on the edge of your seat, straining to hear. Wait! Wait, what’s that?

Oh, right. Your heart, pounding.

MOVIE REVIEW

“A Quiet Place”

Grade: A

Starring John Krasinski, Emily Blunt and Millicent Simmonds. Directed by John Krasinski.

Rated PG-13 for terror and some bloody images. Check listings for theaters. 1 hour, 30 minutes.

Bottom line: A smart, surprising little shocker of a scary movie