Episode: Tomorrow is Yesterday – Season 1, Episode 19 (1966)
Director: Michael O’Herlihy
Writer: D.C. Fontana
This episode starts awesome: the Enterprise being chased by an F-104 Interceptor through the skies of late-sixties Earth! But how? And WHY? Attend the tale, true believers:
After a near collision with a “black star,” the damaged starship gets tossed through space and time back to old Terra. Its decaying orbit allows detection by American radar, and fighters are scrambled to investigate a bona-fide UFO. When the jet assumes an attack posture, Kirk orders it arrested by tractor beam and soon its pilot is aboard the Enterprise. Safe to say USAF Captain John Christopher (Roger Perry) is a little confused.
What follows is Gene Roddenberry’s effort to grapple with the paradox of time travel. Now that Captain Christopher has seen a glimpse of the future, can he be re-introduced to “Old” Earth without disrupting the timeline and inducing the destruction of the Federation? And let’s not forget about the cameras on his now crashed jet: visual evidence of the Enterprise in flight!
Christopher is pretty impressed by the starship, but the real clincher to his status as anachronism is that he talks just like a normal guy. There’s none of that pseudo-Shakespearean delivery we get with so many of the Enterprise’s alien encounters. When told that he can’t be returned to Earth because [made-up time science] he’s all “Fuck you and your timeline, Kirk! I have a family and a job to do. You’re damn right I’m going back.”
But Christopher isn’t the real problem – eventually Spock realizes the guy will have significant offspring and has to go back after all. The problem is the footage back at the airbase. So Sulu and Kirk beam down to retrieve it, dressed in their future-time clown suits so that they can be extra-inconspicuous when Kirk gets arrested. Do I even need to mention that he punches like three separate cops? Sulu makes it back to the ship in one piece, but instead of Kirk they wind up with some poor Air Force officer shitting his britches on the transporter pad (Jim Spencer). It takes a visit from Sulu, Spock, and Captain Christopher to set things straight.
Once everyone is safely back on the Enterprise, Spock and Scotty hatch a new plan. They’ll use the sun’s gravity well as a sling-shot to accelerate the ship to relativistic speed, forcing it (somehow?) back into the recent past, and beam Captain Christopher and the Poopy Pants Policeman into the places they were before the events of the episode transpired (what now?). Then, the Enterprise will continue at relativistic speed but changing temporal direction (somehow?) to go forward in time to their own era. Spock talks like he has the math worked out, but nobody’s fooled and Sulu just has to white-knuckle it.
I’m not going to recreate the entire rant from my review of “The Naked Time,” but keep in mind that Einstein’s theories of special and general relativity had been common knowledge for something like 50 years when this episode came out. Roddenberry still gets it all wrong! Sure, we’ve been using gravity sling-shotting to accelerate space probes for decades, but at no point did any of these craft approach the speed of light. If that were possible, I’d already be wearing a redshirt and a phaser and taking out catastrophic life insurance.
 The first mention of a black hole in the franchise. By the time Jean-Luc Picard is rolling around, they’re pretty thick on the ground.