Stephen Hawking was a well known sci-fi fan. You'd expect as much, given his lifelong dedication to science, and when he got the chance to meet William Shatner, he'd one question in mind.
Hawking was a particularly big Star Trek fan, to the point he was in the Star Trek The Next Generation cast very briefly. Naturally this led to an audience with one of the best Star Trek captains. Speaking with Wired, William Shatner recalled his meeting with the British theoretical physicist. "The great scientist Stephen Hawking – I interviewed him, it may have been his last interview – he said, 'I've got a question for you. What is your favourite episode?'"
Unfortunately for Hawking, Shatner didn't exactly have the best answer to give him. "One of the greatest minds of the 20th century wanted to know… I said, 'I don't know. For God's sake, Stephen. I don't know! It's 55 years ago'."
However, the iconic Star Trek captain was able to offer some worthy insight into how he categorised episodes of the best TV series of its era. "There were some [episodes] that were so good. Star Trek broke itself down into these great episodes. Maybe half of them were really really terrific and the other half were less than really terrific, but really interesting ideas. But I don't have a favourite."
https://youtu.be/JW_P3SRrExw
Well, William Shatner, if you won't pick out the best Star Trek episodes from The Original Series, we'll be more than happy to. Mirror, Mirror, Amok Time, Balance of Terror, and The City on the Edge of Forever would all be worthy recipients, and Shatner – not to mention Hawking – would probably agree.
Of course, it was in his Star Trek movies that Shatner really excelled as Kirk. Perhaps if Hawking had asked the actor about his favourite of these, he would have had more luck getting an answer.