Kirk commands Scott to restart the warp engines at their highest capability, a hazardous procedure that combines matter and antimatter in an inactive state to create a managed explosion and push the vessel away from the planet. This is based on a hypothesis suggesting a connection between time and antimatter, but it has not been attempted before. The restart is successful, thrusting the Enterprise at inconceivable speed from the planet into a space-time warp that returns the ship to 71 hours prior. Spock remarks they now know a way to time travel. Kirk's answer is "Maybe we can try it someday, Mr. Spock."