Another Earth

 It's a metaphor for Rhoda's internal state. The other Earth is "kind of this externalization of the interior world of Rhoda," says Cahill. "She can deal with those ideas of the confrontation of the self just by looking in the mirror, but I felt like there was something very powerful about really externalizing it," by creating a situation where there really is another version of all of us.
And the image of the other Earth provokes a primal reaction in people, says Marling. "We all feel something about looking back at the Earth." She feels strongly that spectacle should always have an emotional context — stuff blowing up for its own sake isn't that interesting. "It's a lot cooler when things are blowing up, and they have a lot of emotional impact."
conceit in the film as a way of exploring "the inner world of who we are, and what it means to be human." Rhoda's desire to become an astronaut and explore this other Earth is a metaphor for exploring your own inner self.
the time we're living in is so alienating and lonely. "We're so connected by emails and skype and text, we're more connected than ever before, "but at the same time, there's something lonely about it." All of us carry secrets that we don't share with anyone, because we're "afraid of being judged, or not loved." And Rhoda has a huge secret, and the only person she could ever really share it with is herself.
 "poetic metaphor," and so a lengthy explanation of it seemed superfluous.
Basically, it's the multiverse, and the idea that string theory suggests there are infinite other universes in which every outcome that could have happened has happened.
And that's called superior conjunction. We don't know, we don't have good photographic evidence, of what lies behind our sun...
"You're always inside the story and you know you are acting in certain ways, and you look for the feelings behind those actions."
Going to work at a high school as a janitor, Rhoda becomes a kind of alien. "She comes back to this place that should be so familiar, and she hasn't been gone that long. But it's such an alien landscape," says Marling. Rhoda is surrounded by high school students who ignore her because she's just the janitor, and she's struck by their "naievete and innocence," while she's been through this insane, life-changing experience. So she might as well be on another planet.
Rhoda hears in a telecast a scientist postulating that the citizens of the mirror Earth might be identical to those on her Earth in every way until the moment they learned of the others' existence. From that point on, the identical people on the different Earths probably began to deviate in small ways, changing their actions. Rhoda hopes her identical self on the other Earth did not make the mistakes she made on the night of the accident.