Another version of Earth appears in the heavens, close enough to us for the human race to ponder the possibilities of a world that is “a mirror to our own” in “Another Earth.”

But this quiet, intimate drama is science fiction in name only. The wildly improbable set-up is merely the jumping off point for an exploration of grief, guilt and redemption that plays out almost entirely between two people thrown together by circumstance.

Rhoda (Brit Marling) is a student at MIT, but even she can’t quite get her head around this new reality — a second Earth visible in the night sky, the one scientists talk about on the news and everybody chatters about in parties.

And she certainly ought to know better than to drink and drive. But she does, and kills a woman and her child. Four years later, she gets out of jail and forlornly sets out to start her life over.

First order of business — go to the husband (William Mapother) and apologize. But on seeing him, a college professor of music utterly crushed by grief, she can’t. John doesn’t recognize her. So actually, she says, she’s here on behalf of a new maid service. Under false pretenses, she starts cleaning his bottle-strewn house — never cashing his checks, never letting on who she really is. It’s atonement and a lovely gesture that and turns downright creepy as their attraction for one another presents itself.

Whatever the survivor of that accident is feeling as he self-medicates, Rhoda is utterly lost. It’s as if she’s given up her right to feel as an act of penitence. Marling, who co-wrote the script with writer-director Mike Cahill, gives Rhoda a zoned-out naivete tinged with regret. This cleaning, this falling into bed with a man whose life she destroyed is the best she can think of, in terms of making things right.

Mapother and his character are more problematic. He lunges from damaged/distraught to romantically interested in this much younger woman in what feels like an instant. It doesn’t ring true. He doesn’t make us feel it.

Cahill makes barely enough of the sci-fi elements — with echoes of “Contact” and “The Island” (people prepping to travel to this new Earth) — never overtly showing what the script suggests, that maybe on this other Earth, the version of Rhoda and John get it right, avoid tragedy or find each other under more honest circumstances.

“If you met yourself, what would you say?”

“Better luck next time.”

Cahill, a photographer turned cinematographer turned documentary co-director (he and Marling did “Boxers and Ballerinas” a few years back) shoots much of the film hand-held, with sudden zooms instead of edits, all underlining the film’s DIY low-budget credentials.

It won’t be to everyone’s taste, but “Another Earth,” opening here Friday, has a contemplative and melancholy air that makes you ponder the questions it poses even if you dismiss the gimmick that it poses them in.

“Another Earth” opens Friday in Orlando.

MPAA Rating: PG-13, for disturbing images, some sexuality and brief drug use.

Cast: Brit Marlin, William Mapother.

Credits: Directed by Mike Cahill, co-written by Cahill and Brit Marling, produced by Cahill, Marling, Hunter Gray and Nicholas Shumacker. A Fox Searchlight release. Running time: 1:32