As one of their own realizes they have a terminal disease, the crew of the Enterprise finds an asteroid filled with a civilization unaware they are not on a planet.
“For the World is Hollow and I Have Touched the Sky” is the 10th episode of the 3rd season of the original Star Trek television series. Written by Rik Vollaerts and directed by Tony Leader, it first aired on NBC on November 8th, 1968.
In the episode, Dr. McCoy finds he is suffering from an illness that will claim his life within a year’s time. This comes as the crew discovers that an asteroid is set to collide with a planet that has a population of billions. Inside that asteroid, they find an alien race who is unaware of their dire situation. Meanwhile, Dr. McCoy begins to find a romantic connection with a woman on the asteroid-planet.