Star Trek (1966–1969)
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Tomorrow Is Yesterday 

The Enterprise is thrown back in time to 1960s Earth.



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Episode complete credited cast:
Hal Lynch ...
Air Police Sergeant
John Winston ...
Transporter Chief
Mark Dempsey ...
Jim Spencer ...
Air Policeman
Sherri Townsend ...
Crew Woman


When the Enterprise is flung back in time while trying to escape the gravitational pull of a black star, they find themselves in orbit around a 1960's Earth. When they are seen by a U.S. Air Force pilot, they beam him aboard but then face the dilemma of what to do with him as he learns more and more about the future. They have to review their initial decision to just keep him when historical records show that his yet-to-be-born son will lead Earth's first successful mission to probe Saturn. Spock devises a plan to do so while also erasing any memory of recent events. Written by garykmcd

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26 January 1967 (USA)  »

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Did You Know?


Majel Barrett uses a very sultry voice for the ship's computer in this episode, similar to how she would later voice M'Ress in Star Trek (1973). See more »


During the slingshot attempt around the Sun, the speeds the characters talk about are impossibly fast. For example, if the Enterprise were traveling at warp 8 between the Sun and the Earth, it would overshoot the Earth by millions of miles within minutes, yet the elapsed time between the Sun and the Earth is clearly about the speed of light even though the ship is supposedly traveling much faster. See more »


[first lines]
Technician Webb: Captain?
Air Force Captain: What is it, Webb?
Technician Webb: A blip, sir. Just came on the screen.
Air Force Captain: How do you read it?
Technician Webb: Aircraft of some sort. By the size of it and the speed, it's not one of ours, sir. Doesn't even read like anything I've ever seen.
Air Force Captain: What was the approach?
Technician Webb: None, sir. It was just there, like it fell out of the sky or something.
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Featured in The Outside Man (1972) See more »


Theme From Star Trek
Written by Alexander Courage
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User Reviews

Back to the '60s
7 July 2009 | by (Italy) – See all my reviews

Tomorrow Is Yesterday introduces the most classic of Star Trek plot devices: time travel. After the original series, it was also used in the spin-offs (minus prequel show Enterprise) and three of the eleven - so far - Trek movies (The Voyage Home, First Contact and J.J. Abrams' reboot), always to great effect. This episode is no exception, especially as it gets more fun to watch as time goes by.

The travel itself is actually just an accident: when a mission goes wrong and hostilities ensue, the Enterprise flies towards the Sun and then away from it as quickly as possible. This, the so-called "slingshot effect", causes the ship to end up orbiting Earth - in the late 1960s! Unfortunately, a pilot working for NASA notices the ship and is taken the hostage by Kirk and Spock, who must now come up with a way to get back home without altering the course of history.

The usual elements of every good time travel story are all present: the discovery of a new age, the problems that derive from it and, of course, the discussions regarding possible paradoxes. What really makes the episode stand out, though, is its sense of fun and prescience: ordinary people's reaction to the sight of Kirk and Spock is always a joy to behold, and it's pretty funny to hear our heroes mention man's first landing on the Moon as taking place on a Wednesday at the end of the '60s: they got it right, weekday and all, a full two years before the whole thing happened. Ah, the pleasures of good sci-fi...

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