Star Trek Reviews

Return to season list

Star Trek TOS - Season 1 - Episode 19

Star Trek TOS - 1x19 - Tomorrow Is Yesterday

Originally Aired: 1967-1-26

The Enterprise is thrown back to 20th century Earth. [Blu-ray] [DVD]

My Rating - 1

Fan Rating Average - 4.9

Rate episode?

Rating: 0 1 2 3 4 5 6 7 8 9 10
# Votes: 48 7 18 13 22 14 34 31 26 24 15

Filler Quotient: 3, bad filler, totally skippable.
- Pretty lame episode with no significant long term continuity.

- The pilot beamed off the aircraft shouldn't have been standing upright after transport because he was sitting in the plane cockpit.
- Kirk mentions that the Enterprise is a "United Earth" ship, which seems to contradict the previously retconned establishment of "The Federation" in the previous episode.
- In the remastered version of this episode the remastered shot of the Enterprise orbiting Earth with the moon in the background has an error. The moon is partially covered in darkness, but in the area covered by darkness you can see stars through the moon as if it were transparent.
- Kirk's interrogator threatens to lock Captain Kirk up for two hundred years. A bemused Kirk replies, "that ought to be just about right." However, in fact it would have to be three hundred years for that line to be "just about right" due to it having previously been established that Star Trek takes place in the 23rd century.

- Kirk said in this episode that there are only twelve ships like Enterprise in the fleet at this time.
- Spock's rank is established to be that of lieutenant commander in this episode.
- This episode was meant to originally be a follow up to the time warp in The Naked Time.

Remarkable Scenes
- The Enterprise being chased by US fighter aircraft.
- The look on the pilot's face after having been beamed up.
- Spock meeting the pilot.
- The computer being awkward.
- The pilot arguing that his sudden absence from Earth would have just as adverse an effect on the timeline as his returning with information from the future would followed by Spock countering the pilot's argument by claiming that according to his research, the pilot never contributed anything significant to history anyway. Ouch.
- Spock discovering that the pilot must be returned to Earth after all so that he may father a child who goes on to make significant contributions to history.
- The Air Force sergeant's behavior after having been beamed up.
- Kirk's interrogation.

My Review
A gravitational anomaly accidentally propels the Enterprise into the past whereupon the crew accidentally contaminates the timeline. I've never been a fan of the use of time travel in science fiction mostly because the power to travel through time is unimaginably dangerous in its implications and the resultant time paradoxes are a storytelling nightmare. Most time travel stories irresponsibly gloss over this stuff and this episode is no exception. While this episode goes to great length to clean up the timeline to remove all contamination, it does so at the expense of the credibility of the Enterprise's century because we've now learned that the magic time travel technique Spock invented in The Naked Time is a pretty damn reliable tactic. Twice now we've seen the Enterprise travel through time just by Spock crunching some numbers and plugging them into the ship's computer and twice now the implications of this power have been ignored as relatively trivial.

The truth is that no society, not even one as enlightened as the Federation, or United Earth, or whatever they're calling themselves now is going to ignore this kind of power the way our heroes seem to be doing. If Spock's magic time travel formula is as accurate, useful, and reliable as depicted in this episode and as depicted in The Naked Time, then why not go back in time and erase the Earth-Romulan war in the same fashion they erased their mistakes in this episode? Why not travel into the future in order to plunder its technological advancements? Why not do any of a million possible things this sort of technology enables? I'll tell you why. Because the writers have failed to properly comprehend what would realistically ensue if time travel technology were actually invented.

But misuse of time travel isn't this episode's only sin. I'd be negligent if I didn't mention the embarrassing "sensual computer" scenes, or the fact that Captain Christopher managed to escape his quarters because nobody felt it necessary to place a guard, or the even more idiotic decision by Spock to inform Captain Christopher of the significance of a child he hasn't even had yet. It's a good thing Spock's magic time travel formula let them erase that mistake.

What was with that whole transporter merging memory wiping thing anyway? Kirk says he'll transport Captain Christopher to a time before any of this happened which will cause him to have no memory of these events. Is the transporter somehow combining the uncontaminated Christopher with the contaminated Christopher and erasing the memory of future events? If so, since the goal is to no longer have a contaminated Christopher, then why not just blow the contaminated Christopher right out the airlock instead rather than risking a dangerous transport operation in the middle of the whole silly slingshot effect? Doesn't this transporter merging of the two of them effectively kill the contaminated one anyway? Because I fail to see the difference between that and merely executing the contaminated version. Either way an uncontaminated version lives out his normal life as history intended.

As written, this episode is simply riddled with far too many technical and logical problems to be worth many points. Let's all hope the next time they use time travel on Star Trek they treat the subject with a bit more care and take the implications of what would realistically ensue due to their plot device a bit more seriously.

The following are comments submitted by my readers.

  • From 411314 on 2009-06-15 at 8:45pm:
    I really enjoyed this episode and seeing the reaction of a character from when this was made seeing the future as presented in Star Trek. The slingshot effect didn't bother me at all. Obviously, Star Trek takes place in a fictional world where the rules are different from what they are in the real world.
  • From Arianwen on 2010-07-21 at 2:15am:
    Also one of my all-time favourite episodes. The dialogue was excellent, the acting on a par to the dialogue. I really think this is one of Shatner's best episodes.

    The slingshot effect is probably very daft (so is the whole time-travel thing; they managed to drop their visitors off at the exact moment after they had taken them?), but then so are most of the premises of Star Trek or any other Sci-Fi show. (Ever seen Doctor Who? Now there's suspension of disbelief for you.)
  • From Strider on 2012-10-24 at 5:50am:
    This is one of my favorites, too. I liked that Captain Christopher was strong and not easily intimidated, and that he both gave respect and earned the respect of the Enterprise's officers. I could really see him becoming a starship captain if he'd been born at the right time. When Spock stopped him from holding them hostage at the end of the episode, I got the sense Spock knew what to do because he knew Jim so well, and Captain Christopher was the same kind of man.

    As far as time travel goes...if this happened to me and my crew, it would never make it into my log. I wouldn't want Starfleet or the Federation to have that information.
  • From Alan Feldman on 2013-02-11 at 5:33am:

    Ridiculous time-travel problems, but if you can swallow them, this can be a fun episode to watch. Ok, let's go!


    Near the end of the episode they're heading for the Sun. What do we see on the screen? Stars whizzing by and no Sun. Where is the Sun? They're heading straight for it and it's not on the screen! What are all these "stars" moving by doing in the Solar System? At times the ship doesn't look like it's moving at all.


    There's another problem with the scene with the Moon in the background: Not only can you see stars through its dark side, the moon, as rendered, is WAY TOO BIG! It wouldn't look any bigger from low-Earth orbit than it does from the ground. Still yet again, the remastered effects make things LESS realistic.


    Yeah, the time-travel paradoxes are a nightmare. My additional question: How can you change a future that already happened? Does this question even make any sense? If it does, then they can't screw things up; otherwise, the Enterprise and its crew wouldn't already be as they are/were in the 23rd century in order to go back to the 1960's to be as they are/were then to mess things up in a way that makes everything happen as it did the "first time", as there is no "second time". Got it?

    And what about the butterfly effect? Well, it turns out that it is irrelevant.

    OK, analysis: There is a time interval in which there are four Enterprises at the same time. One is the one that first went back in time. The second is the Enterprise going forward again, splitting off from the first. If those on the second Enterprise could see their counterparts on the first one, they'd see them going backwards, and vice versa. The third Enterprise is going back in time as it heads toward and then away from the Sun. The fourth is the ship going forward in time again, back to the 23rd century. Again, each crew would see the other going backwards. And, as I mentioned in my review of "The Naked Time", there will be two overlapping enterprises near each turnaround point. Sorry my diagram didn't make it over intact in that review. Think of it this way: You're in one place at 2:00 going backward in time. At 1:00 you switch to going forward in time and at 2:00 your in another place. So at 2:00 you're in two places at the same time, going backwards in one, and forwards in the other. At 1:00 your two places are overlapping and begin to separate. So from the viewpoint of an outside observer, you suddenly appear as two overlapping ships that separate, with one crew going forwards and the other going backwards. Cool, huh?

    Things like this are what you'd have to accept in order to believe in time travel, unless you make a discontinuous jump in time, in which case you can avoid this overlap paradox.

    As for Captain Christopher: If Spock and crew got the timing just right, Christopher was being beamed out of the plane by the Enterprise going forward in time the first time at the same time that the Enterprise going forward in time for the second time beams him back in. And that time one beaming him back is going faster than warp 8 while beaming him back! If Spock's timing is off, there will be a time interval with either no one in the plane, or two overlapping pilots in the plane. Yuck! Now the hardest part. Does the plane break up, or return to base? Both possibilities are going forward in time. The episode has him doing the latter, but I think in fact it would be the former, with our new Christopher ejecting or dying in a crash. Why? At this point there are four Enterprises. And one of them destroys the plane with a tractor beam. None of the other three can do anything to prevent that, so the show is inconsistent. And he would later appear out of nowhere to snoop around the base with Kirk and Sulu. Sometime after that he'd be beamed up and never appear on Earth again! But that's not how it happened on the show. We have the same problem for the sergeant encountering Kirk and Sulu, but this has the same contradiction problem. So according to the episode, all this trickery somehow wiped out the version with the plane breaking up and the sergeant finding Kirk and Sulu looking for films. Sorry, that doesn't fly. It's a total mess. Well, I almost got it to work.

    So what would this look like to an outside observer? This is basically what I said above, but in chronological order. She'd first see the Enterprise, with our "stowaways" on board, pop out of nowhere. It would immediately turn into two overlapping ships and would begin to separate. (This violates conservation of energy, energy in the form of mass, i.e.) The overlapping ships then continue to separate with one heading for the Sun, with its crew doing everything backwards, and the other heading for Earth, doing everything forwards. Both have Christopher and the sergeant on board. Both Enterprises then pass near each other by Earth. One transports Christopher from the plane to the ship. The other from the ship to the plane. Note that the Enterprise coming from near the Sun is traveling at over warp 8 while they beam the stowaways back to Earth! The outside observer would then see another pair of Enterprises pop out of thin air and separate. One would be in orbit with the crew going forwards. This one would beam Christopher and the sergant up to the ship. It would later head for the Sun. The other would head for the black star with its crew going backwards. So we find that at two points, one Enterprise would beam people up from Earth, and another would beam them back down. Then the unavoidable contradiction.

    AEF, a.k.a. betaneptune
  • From Scott Hearon on 2014-03-21 at 10:34pm:
    Not a very good episode, for all of the reasons that Kethinov points out. Time travel is always a tricky one, and unless handled very deftly, a ruinous one. Some people don't mind the paradoxes, contradictions, and willful ignorance of writers towards the ramifications of time travel. I, however, am often greatly bothered by sloppy time travel stories. This was one of them.

    I found Kirk's attitude in this episode pretty annoying, too. Partially due to the script and partially due to Shatner being Shatner, the smarmy, self-satisfied demeanor was a nuisance. His sarcasm and condescension towards the Air Force officers, who were only doing their jobs, seems far beneath one of Kirk's station.

    If had been watching this episode back in 1966, I probably would have been pretty disappointed. Much of the story takes place on "modern" Earth, which is not what I'm watching a science fiction show for. Add in the fact that the "science" in the fiction is weak, and it's not a very strong entry into the canon.
  • From Alan Feldman on 2014-11-28 at 6:10pm:

    Correction to my first post:

    I got the time-order of events as seen by an outside observer not quite right, or at least not clear enough! I will correct it here. (Recall that we get multiple ships as follows: Say at 1:00 you're going forward in time. At 2:00 you start going backward in time. So at 1:00 you're going backward in time. And now your ship is in two places at the same time!)

    There are basically as many as five ships from the viewpoint of an outside observer present at a single time. As viewed by our heroes, there is one ship on one trip, but divided into five parts in time. I drew myself a space-time diagram to figure this all out, but unfortunately I am unable to post it here. I'm forced then to leave this as exercise for the reader: Draw 7 parallel horizontal lines on a sheet of paper (landscape mode). Label them t0 at the bottom through t6 at the top. Draw a vertical line on the left (leave a little room for ship A). That will be the black star. Draw a vertical line down the middle to represent Earth, and one on the right to represent the Sun. Draw the path through space-time based on my description below.

    A - going forward in time, from before any of this happened, to the encounter with the black star, t0 -> t6.

    B - going backward, from the black star to earth, t6 -> t2

    C - going forward, from earth until zooming toward the sun, t2 -> t5

    D - going backward, as they zoom to, and then away from, the sun, t5 -> t1

    E - going forward, passing Earth for the beam-backs at t3 and t4, as they return to their own period, t1 -> t6 and forward.

    An outside observer would see A through E as five distinct ships. Here's the timeline. Each t<n> is a point in time:

    t0 - Just one Enterprise, zooming along before any of this happened.

    t1 - Ships D and E appear out of nowhere at the same place -- yes, overlapping -- and then separate. Inside D, from t1 to t5, things are going backwards. This is the second turnaround from going backward in time to forward in time as seen by our heroes. Ship A is also present.

    t2 - Ships B and C appear out of nowhere at the same place and then separate. Inside B, from t2 to t6, things are going backwards. This is the first turnaround from going backward in time to forward in time as seen by our heroes. Ships A, D, and E are still present. There are now five ships existing at the same time!

    t3 - Ship C beams up the pilot, while at the same time ship E beams him back to the fighter jet. Ships A, B, and D are still present. Shortly thereafter, the fighter jet breaks up.

    t4 - Ship C beams up the sergeant, while at the same time ship E beams him back to the base. Ships A, B, and D are still present.

    t5 - Ships C and D merge together and disappear. Ships A, B, and E are still present. This is the second turnaround from going forward to backward in time as seen by our heroes.

    t6 - Ships A and B merge together and disappear. This is the first turnaround from going forward to backward in time as seen by our heroes. Ship E continues to the next episode.

    At some unknown time between t1 and t5, ship D reaches its closest point to the sun, and then reverses to move away from the sun.

    Kirk and Sulu are on the base at some time period between t4 and t5.

    From t2 through t5 there are five ships present!

    There are then two problems: (1) the sergeant would remember what happened when he was on the Enterprise, and (2) at time t3, ship C destroys the fighter jet, while ships A and E do nothing to put it back together. Too bad for Captain Christopher!

    But if we follow what Kirk says, from Christopher's viewpoint, what happened from the time when he was beamed up to the time when he was beamed back, somehow "never happened". And similarly for the sergeant. This is quite problematic for what the outside observer sees!

    Yes, this is what you get when you work it out. And having multiple Enterprises popping out of thin air, so to speak, and disappearing, violates conservation of energy (energy in the form of mass), which is one of, if not the, most firmly established laws of physics.


    Some new comments:

    Spock complains about "poor photography" (funny!) while he's smearing up the film with his hands!

    Capt. Christopher is credited as _Major_ Christopher in the ending credits.

    Can you imagine what it would be like to be transported by surprise, and not having watched Star Trek? I think Capt. Christopher was surprisingly rather underwhelmed by it. I mean, really. He was flying a fighter jet, then suddenly he's standing in the transporter, and his first words are, "You speak English." Only later does he start asking the obvious questions and such. He then adjusts to the situation rather quickly. The sergeant's reaction seemed like a much more likely and believable one to me -- well, perhaps a little too overwhelmed.

    "Now the experts can figure out who you are, what you are."

    "I'll have it disassembled and examined. We are not dummies, mister. We know how to find out things we want to know."

    Who are these experts, and how can they be this good?


    To Kethinov, who asked, "What was with that whole transporter merging memory wiping thing anyway? . . ."

    Yes, the beam-merging makes no sense. But it's not just that. They have to wipe out the part where Christopher's jet is destroyed. I don't see how the beam-merging is supposed to fix that. It's nuts, but if you go with it you get a fun episode. I still enjoy watching it, though I do cringe during the beam-mergings. And the reason to watch it is the interactions between our heroes and 1960s people. Oh, and the computer being affectionate, with Spock being disgusted by it being female! "Computed"!


    To Scott Hearon:

    I like the scene with Kirk being questioned by the Col. Fellini. I think Kirk did just fine. So he made a single smart-ass remark. I don't think it's _that_ much of a big deal. And here we have clear evidence of our heroes normally being 200 years, not 300, in the future (from c. 1967).

    As far as this episode taking place on "modern Earth," we also have our heroes and the Enterprise from 200 years in the future interacting with present-day people (assuming you're in the late 1960s, of course). That, and the fact that there is some time travel going on, make it science fiction.

    Weak science in just this episode? The entire series is loaded with weak science, and occasionally really, really bad science ("The Alternative Factor" comes to mind). Still a fun show to watch, except for a very few episodes.

    AEF, a.k.a. betaneptune
  • From Alan Feldman on 2017-07-23 at 10:45pm:

    Another problem with the scene with the Enterprise, Earth, and Moon in

    The lighting on the ship is not consistent with that of the moon. From the moon we can see that the Sun is behind us. But the Enterprise is lit from a Sun in front of us. What's the point of trying to make things more "realistic" if they screw things up like this? It would not have taken much to get it right. So we have at least three things wrong with this picture:

    1) Can see stars through the dark side of the moon.

    2) Moon is way too big. (It wouldn't look any bigger from low earth orbit than from the ground. And you can't see that much detail from the ground. And it can't be a telephoto shot because in such a shot the engines would _look_ parallel or at least _much closer_ to parallel.)

    3) Angle of the sun is different for the ship than for the moon. (Explained above.)
  • From Chris on 2018-02-08 at 5:27pm:
    One additional problem with this episode aside from everyone else's!!!

    Cap't Chris somehow says, "You seem to have a lot of 'em..." Referring to problems on the Enterprise, yet he's seen no problems of any kind!!!

    THANK YOU VERY MUCH!!! Just sayin'... ;-)

Prove to me that you are a real person and not a spam robot by typing in the text of this image:

Return to season list