Star Trek (s01e19)

Tomorrow Is Yesterday

by D. C. Fontana, directed by Michael O’Herlihy

Release: 26 January 1967
Format: TV Episode
Genre: Science Fiction
Audience: Adults
Content: Definite Time Travel
Original Language: English

Darn those high-gravity black stars! Always accidentally throwing starships hither and yon through time. Although in this case, the crew of the Enterprise manages to correct all the problems they caused by beaming 1960s Air Force pilot Captain John Christopher on board.

— Michael Main

Spock: Fifty years to go. Forty. Thirty.
Kirk: Never mind, Mr. Spock.
Spock: [silence]

DEBUT

Star Trek (s01e19), “Tomorrow Is Yesterday” (NBC-TV, USA, 26 January 1967).

VARIANTS

1 English variant

TAGS(SPOILERS!)

Time Periods

Circa AD 1960 to 1969: 1969
Circa AD 2200 to 2299

Time Travel Methods

High Speed, Angular Momentum, Gravity, Cosmic Strings, etc. Cause Time Warp: “Mr. Scott and I both agree that the only possible solution is a slingshot effect, like the one that put us here. My computations indicate that if we fly toward the sun, seek out its magnetic attraction, then pull away at full power, the whiplash will propel us into another time warp.”

Themes

Never Change the Past!: “We cannot return him to Earth, Captain. He already knows too much about us, and is learning more. I do not specifically refer to Captain Christopher, but suppose an unscrupulous man were to gain certain knowledge of man’s future. Such a man could manipulate key industries, stocks, and even nations, and in so doing, change what must be. And if it is changed, Captain, you and I and all that we know might not even exist.”
Technology and Science from the Future: “Uh, Colonel, would you mind being careful with that?”

Fictional Tags

Groupings

TIME TRAVEL ITINERARY (SPOILERS!)

From an unspecified place, AD 2267 ⋙ to above Omaha, Nebraska, 1969. Round trip.

INDEXER NOTES (SPOILERS!)

Time Travel Problems—<a href='C._R._Berry'>C. R. Berry</a> gives <a href='http%3A%2F%2Ftimetravelnexus.com%2Ftime-trek-star-trek-the-original-series-tomorrow-is-yesterday%2F'>a nice discussion</a> on why beaming Captain Christopher and the sergeant back to the time they were first taken makes no sense, won’t erase their memories, and opens a whole ’nother can of worms. He also gives an easy solution that the writers could have taken.