Doppelgänger (Doppelgänger)

The doppelgängers are a species almost entirely identical to Humans, only mirrored, living on a Counter-Earth, a planet in Earth's orbital period, but on the opposite side of the sun.

Biology
Externally, the doppelgängers are completely identical to Humans. Internally, all functions of their physiology are exactly the same as Humans, with the only difference being the fact that the organs of the doppelgängers are reversed from the Human orientation. Compared to Humans, they all appear to have situs inversus.

Culture and society
The society of the doppelgängers, for reasons unknown, is exactly identical to Earth's society at the same time, with the same countries, languages, cultures, laws, and developments. However, almost every part of their society is a "mirror" of Earth. For instance, their languages, while spoken the same as Earth's languages, are written backwards, and the driving side for every country is reversed as well.

Technology
Like their society, all technology used by the doppelgängers are identical to their counterparts on Earth, only reversed, with controls and inner workings oriented opposite to the way they normally are on Earth, making them rather distinct from a technical perspective. However, their electrical circuits still function exactly the same as Earth circuitry, as electrical flow is a constant on both worlds.

History
The doppelgängers arose on a planet in the same orbital path as Earth, just on the other side of the sun, as a sort of Counter-Earth. For reasons unknown, likely supernatural, the doppelgängers and their planet developed exactly like Earth, with their planet mirroring the same landscapes and conditions while their society reflected the same developments, with the only difference being that the doppelgängers' world was "reversed," as if viewed from a mirror. In 2069, the doppelgängers' version of EUROSEC detected Earth, registering it as an unidentified planet, and the findings were leaked to an Eastern power. In order to prevent the East from reaching Earth first, EUROSEC convinced the doppelgängers' version of NASA to launch a crewed mission to Earth, sending NASA astronaut Glenn Ross and EUROSEC astronaut John Kane on the three week journey.

At the same time, Earth sent the Human Glenn Ross and John Kane on the exact same mission to the doppelgängers' world. The Human astronauts used their landing craft, the Dove, to attempt to land on the doppelgängers' planet, but end up crashing during a thunderstorm. Human Ross and Kane are picked up by a rescue team, having had landed in the doppelgänger Mongolia. Assuming that they were their doppelgänger counterparts, Ross is questioned by doppelgänger EUROSEC security chief Mark Neuman, while Kane dies of his injuries. Neuman demands to know why Ross and Kane abandoned the mission, but Ross insists he made it to the other planet, still believing that he had somehow returned to Earth. Meanwhile, doppelgänger Ross and doppelgänger Kane were presumably going through the exact same scenario on Earth.

Ross is allowed to return to "his" home and wife, soon seeing all the reversed aspects of the doppelgängers' planet, such as the backwards writing and different driving sides. Realizing that he truly is on the other planet, he attempts to tell this to the other doppelgängers, but they do not believe him. However, doppelgänger EUROSEC director Jason Webb believes him after seeing the orientation of Kane's organs during his autopsy, which were reversed relative to the doppelgängers. Doppelgänger Webb has the Dove retrofitted with doppelgänger technology to allow Ross to return to Earth, but assuming that electric currents were reversed as well, reverses the polarity of electrical circuits. When Ross took off, the ship malfunctioned and crashed on the doppelgänger EUROSEC Space Centre, destroying most of it and killing all who knew of the truth of Earth and Counter-Earth. The same fate presumably met doppelgänger Ross and Kane. It is unknown if the doppelgängers ever tried to reach Earth again, or vice versa.

Appearances

 * Doppelgänger (1969)