Most people must have, at some time, pondered the possibility of doppelgängers or of a parallel world where an Identical version of themselves exists, and the dichotomy of whether the other them would be a better or worse person, or exactly the same. The concept has certainly provided a rich source of inspiration for sci-fi, fantasy and horror writers, from Victorian novelists to contemporary screenwriters such as JJ Abrams with his mind-bending TV series Fringe.

While quantum physicists are debating the possibilities of parallel worlds, astronomers, interested in slightly more tangible realities, are busy exploring space for earth-like planets in the hope of finding somewhere that will sustain human life (also the subject of countless sci-fi stories). The what-if scenario of parallel worlds and the search for an Earth-like planet collide in the award-winning Another Earth from multi-hyphenate filmmakers, writer-director Mike Cahill and actress-writer Brit Marling.

The lives of Rhoda (Marling), a brilliant young student, and a music professor, John Burroughs (William Mapother from Lost) are tragically thrown together and ripped apart at the same moment a planet identical to Earth is discovered in the night sky. Four years later they meet again and given the circumstances of their previous encounter develop a relationship that is rather disturbing. It has taken those four years for Earth to make radio contact with the mirror planet, clearly visible in the sky, which does make you wonder how they managed to broadcast from the moon in the ’60s, or why no one (US, Russia, China or India) has attempted to visit the planet except for an Australian entrepreneur, who runs an essay competition to give someone a seat on his private shuttle, which Rhoda conveniently wins, leaving her with a difficult decision.

Despite its title, this is not hard sci-fi, which, after being bombarded by fatuous effects-driven blockbusters over the summer, is not necessarily a bad thing. However, it is a hybrid indie genre movie, like Never Let Me Go and Franklyn, which can divide, or even alienate, audiences. Sci-fi audiences, in general, tend to be more open-minded in these matters, although far more critical of the science element if they show a lack of cohesive logic, which this film does on occasion. For example, why don’t the orbits of the two planets affect the gravitational pull of each other, or, considering the butterfly effect, the probability of the two planets being identical is infinitesimal?

However, if you are prepared to suspend disbelief and overlook the scientific anomalies, this plays out as a solid, low budget, indie human drama about dysfunctional people and their relationships, but with sci-fi elements lingering in the background, making it the perfect antidote to the more vacuous Hollywood blockbusters.

Another Earth is in cinemas from Friday 9 December.

Watch our interview with director Mike Cahill, who addresses some of the scientific questions.

Mike Cahill by SFLTV

And for a far more scientific analysis of parallel universes, listen to our interview with Oxford University quantum physicist David Deutsch.

Parallel Universes by scifilondon