Star Trek: 10 Terrible Ways To Time Travel
9. The Atavachron
You certainly won't find this at your local library (assuming you still have one)! A fairly neat solution to an explosive problem for the pre-warp inhabitants of Sarpeidon, that is if they chose to go willingly, the Atavachron is still a lousy way to time travel.
Down on Sarpeidon in All Our Yesterdays, Kirk, Spock, and Doctor McCoy meet lone librarian Mr. Atoz, as in 'I don't give a…' when it comes to explaining what those data discs are really all about. Thinking they're just having a browse without borrowing, the trio soon find themselves on the other side of the Atavachron time portal at different points in Sarpeidon's past. Naturally, Kirk almost immediately gets himself locked up and also has to put up with some pretty dodgy accents. "He's a witch!" "Witch!" Witch!" Witch!" Nope, still can't place it… milord! Spock and McCoy have it worse off, however, in Sarpeidon's ice age.
Aside from trapping unsuspecting Starfleet officers, the regular operation of the Atavachron meant making changes to the user's cell structure and brain patterns that prevented them from returning from the past. Thoroughly unprepared for the trip, Kirk, Spock, and McCoy would die within hours if they didn't make it back to the future where Sarpeidon's sun was about to blow up. Plus, 5,000 years ago, Spock went all weird (again). Great episode. Not so great type of time travel!