Star Trek TOS’s Duplicate Earths - A Great Story-Telling Technique

I always loved the stories that featured a duplicate Earth in the original series of Star Trek (TOS). I believe it is a largely forgotten aspect of TOS, and I am unaware of anything similar being explored in the subsequent Star Trek series and movies. I’m sure that if we did a survey of each series, we could find many, many examples of Earth-like people living in Earth-like situations, but that is not what I am referring to here.

I am also not referring to the idea of parallel universes (presently known as the “multiverse”), with duplicates of every person in each universe, which was also developed in two TOS episodes, the most famous and echoed one, Mirror Mirror.

I am referring particularly to TOS episodes that featured a duplicate or near duplicate of the Earth itself found in another part of our own galaxy. The idea appeared in all three seasons and featured three episodes with a duplicate Earth as well as several more episodes where the visited planet’s history has some parallel to Earth’s. Star Trek’s creator, Gene Roddenberry, must certainly have been fond of this story idea as well because he wrote two of them himself.

The Duplicate Earth story-telling technique allowed Kirk and his crew to visit with people situated in past times from our own history. But even better, the technique allowed the series to explore, in a real and meaningful manner, the possibilities of what might have happened had our history taken another direction. This is, in my opinion, a more effective way of telling a such a story than using an alternative timeline or universe. Alternative timelines and universes, by their very nature, take us away from the "real" universe we live in. Alternative timelines are, well, alternative--they are different from our "real" timeline and can be fixed by going back and repairing the problem. Similarly, an alternative universe is not our own universe--it's some far off other world or dimension. Rather than casting the story into this alternative reality, the duplicate Earth's history takes place right here in our own galaxy and universe. It's not so unreal or easily erased--like a holodeck, which is simply turned off at the story's ending.

The duplicate Earth’s existence is often presented as a mystery. The planet’s mere presence on the bridge’s screen provides a sense of awe and mystery. “Another Earth!” someone exclaims. Right away we are pulled into an almost magical sense of curiosity. How could it even be there? We want to know how it’s the same and how it’s different – and what happened to them that didn’t happen to us.

While they never completely explain the existence of the duplicate planets, Star Trek liked to stress the “science” aspect of science fiction, and posited a theory for the phenomenon, naming it “Hodgkin’s Law.” (You can read all about it here: http://memory-alpha.wikia.com/wiki/Hodgkin%27s_Law_of_Parallel_Planetary_Development). This theory attempted to explain how other planets could have Earth-like people on them but also similar Earth histories. While the theory itself would probably not stand up to scientific scrutiny, it is only mentioned in passing and does not really take away from the magical, mysterious atmosphere of the episode.

Another theory, also explored in a later series, suggested that advanced aliens “seeded” people around the galaxy. This, again, did not attempt to explain the great (and fun!) mystery of how there could be physical duplicates of the Earth and, even more mysteriously, have nearly the same historical events--but with very interesting differences. And keeping it a mystery makes it all the more interesting as far as I’m concerned.

A quick survey of these episodes follows. There are five episodes where the Earth is more or less duplicated as charted below. I’ve also included two more that are near fits.

Season 1 - Miri

The Enterprise visits an exact duplicate of the Earth. The active civilization ended in the 1960s (of this planet) when a biological weapon killed off every adult on the planet. Only the children, who now grow very slowly, live there, but die when they finally become adults. Writer: Adrian Spies

Season 2 - The Omega Glory

The Enterprise visits a near duplicate of the Earth with a primitive population. The people reverted to a more primitive state after a civilization-ending war that still rages to this day between the “Asian” and “White” races. Writer: Gene Roddenberry

Season 2 - Bread and Circuses

The Enterprise visits a near duplicate of the Earth with a modern day (1960s) civilization. The difference here is that Rome never fell. (This is the episode where Hodgkin’s Law is mentioned.) Writer: Gene Roddenberry

Season 3 - The Paradise Syndrome

While not identified as a duplicate Earth, the Enterprise visits an Earth-like planet that mysteriously contains American Indians, living as they would without contact with more modern men. Writer: Margaret Armen

Season 3 - All Your Yesterdays

Also not identified as a duplicate Earth, the Enterprise visits a planet that is about to be destroyed by its own sun. Its people’s only escape is to use technology to escape safely back in the planet’s own history, which is remarkably (from what we see of it) similar to Earth’s own history. Writer: Jean Lisette Aroeste

Season 2 - Patterns of Force

Close but not quite - The Enterprise comes to a duplicate of Earth created artificially by a violation of the Prime Directive. A Federation expert transforms the planet into a Nazi government, copying all aspects of it, thinking that if run benevolently, it will be the most efficient government for the planet. Writer: John Meredyth Lucas

Season 2 - A Piece of the Action

Close but not quite - The Enterprise must repair the damage done to highly imitative people who create a planetary duplicate of the 1930s mob gangs of Chicago. The damage was created accidentally by a visit by a prior ship that pre-dated the Prime Directive. Writer: David P. Harmon

And at each of the episodes’ endings, we are left behind as we watch the great ship fly off into the night of space. We are left to ponder what has happened in our own history and what might have happened, if only…

So, rather than the more popular technique of going to alternative universes or timelines, the episodes described above gave us a fun and ultimately more real way of visiting another version of the Earth. And I would love it if future iterations of the show tried this technique again.