The passing of Stephen Hawking is a terrible loss to the world of science, but it's also a blow to the world of epic television cameos. Throughout his life, the theoretical physicist showed up on a number of nerdy television shows like The Big Bang Theory, Futurama, The Simpsons, and, of course, Star Trek: The Next Generation. On Trek, Hawking appeared in the 26th episode of Season 6, entitled "Descent, Part 1."
The 1993 episode found Brent Spiner's Data playing cards on the Enterprise's Holo-deck with some of the most notable scientific minds in history: Isaac Newton, Albert Einstein, and Stephen Hawking, who tells the group a highly scientific joke that Data then has to explain to Newton. He's the only member of the group who doesn't have a grasp on "the relativisitc curvature of space-time."
Einstein calls Hawking's bet, saying that he is bluffing, but the physicist counters with "Wrong again, Albert" before throwing down four of a kind and winning the hand.
To date, Stephen Hawking is the only historical figure to portray himself within the Star Trek universe. Those who have an intimate relationship with the Star Trek universe like the actors from the original show and new movies mourned Hawking's death on social media.