This has always bothered me. In Quantum Leap, the string theory they explain in the show suggests that one can travel to random points in time within their own lifetime.

The Quantum Leap project exists in 1999, and episodes involve leaps to times before 1999, but why not anything after 1999?

I know the premise of the show was to fix something that went wrong in the past, but could there future events that need fixing too? You would think that Sam Beckett would be alive beyond 1999. I would like to think that this would make an interesting episode where he leaps into someone who exists in the future. Al finds him and they have no clue who Sam leaped into or what needs to be fixed. They would need to figure out what will go wrong to fix it. Their computer, Ziggy, is wrong most of the time anyways.

  • 1
    Sam became displaced in time from the experiment and never returned to his body. So 1999 was the final "year" of his life. Oct 13, 2014 at 19:20
  • 2
    It Is impossible to go beyond the temporal devastation caused when the moon got knocked out of the solar system, duh. Oct 13, 2014 at 19:31
  • Back when Quantum Leap was on the air, it was difficult to imagine the distant future of the 21st century. Apr 16, 2015 at 20:58
  • I recently started the show on Hulu & it seems to have a fix on the 50's 60's & 70's guess because those were the creators favorite time periods or something I guess. To bad they couldn't have had him go back any further than the mid 20th century. Would have been interesting to see Sam leap into a soldier in the American revolutionary war or a 16th century pirate.
    – Jack
    Jul 10, 2017 at 4:36
  • 1
    Oh boy........!
    – user60893
    Jul 10, 2017 at 8:35

4 Answers 4


According to the finale:

Sam never returns home. So he doesn't have any lifetime after 1999...


Given that past events are malleable (since that's the whole premise of the show), that would mean that the future is always in flux. There would be no way to get a solid lock on anyone further forward than the project itself, because that would necessitate Ziggy knowing future events. Sam could never "put right what once went wrong" because a) it hasn't gone wrong yet, from the POV of the project itself, and b) there would be no way to know what to fix, because there would be no way to access the records.

Notice when Al describes the changes that Sam has made, he can only explain as far as his relative present -- he has no information about any post-1999 events since, as far as Ziggy's database is concerned, they haven't happened yet.

So, it would be more accurate to say that the Quantum Leap project allows a person to leap between the days of his or her lifetime from birth until the point where they stepped into the machine.


It was considered, but vetoed by Bellisario, possibly leading to the series cancellation:

An unused ending for the final episode (then only the fifth season finale) of Quantum Leap exists in which Al himself leaps in order to find Sam, and the pair end up on a space station in the far future. Reportedly, the direction NBC wanted the show to go in was for Sam to stay in the future and take on a young sidekick, which makes little sense, since how could he alter what once went wrong when it hadn't happened yet? Series creator Donald Bellisario wasn't very inclined to cooperate, leading to the show's cancellation, reportedly.

  • Is it possible to see this footage?
    – Wallnut
    Jan 10, 2017 at 10:05
  • I have a vague memory of seeing it in a "next time on Quantum Leap" bit, but I can't find it online, so I might be misremembering.
    – FuzzyBoots
    Jan 10, 2017 at 11:09
  • "Bellisario has said no script exists and that he does not know where this idea came from." - en.wikipedia.org/wiki/….
    – Valorum
    Nov 12, 2023 at 9:09

I assume that NBC did not pour enough money to create the look and feel of the post-1999 (futuristic cars, high rise buildings and people's way of life) akin to Back to The Future II. As a result, they fixed the story in a way that Sam could only travel back in time during his lifetime (the string theory as opposed to the grandfather paradox in BTTF trilogy). Beside that Quantum Leap does blatantly violate the law of time in which a traveler can travel from one point of time to another but not from place to another.

  • 1
    This seems to be pure guesswork. Can you offer anything by way of evidence to support these bold statements?
    – Valorum
    Dec 16, 2018 at 19:00

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