PHOTOS | Real-Life Men of Science Who Made 'One Giant Leap' into 'The Big Bang Theory'
For as many shenanigans the gang gets into on The Big Bang Theory, we sometimes forget that they're among some of the most brilliant minds on the planet. So, it stands to reason that Sheldon (Jim Parsons), Leonard (Johnny Galecki), Howard (Simon Helberg), and Raj (Kunal Nayyar) would occasionally run into real-life scientists, astronauts, and tech moguls.
Elon Musk -- Howard meets Tesla founder Elon Musk, quite by chance, while serving Thanksgiving dinner to the homeless. What a caring guy!
Ira Flatow -- Former Newton's Apple host and science personality Ira Flatow has made several guest appearances on The Big Bang Theory, often interviewing the guys about their latest scientific exploits on his radio show.
Bill Gates -- In the Season 11 episode "The Gates Excitation," Penny (Kaley Cuoco) gets the opportunity to host renowned tech billionaire Bill Gates at work when his company wants to partner with her pharmaceutical company.
George Smoot -- During a conference in San Francisco, Sheldon and the guys encounter Nobel laureate Dr. George Smoot, who conducts a keynote lecture at the event.
Mike Massimino -- Buzz Aldrin isn't the only astronaut to pop up on The Big Bang Theory! Space Shuttle veteran Dr. Michael J. Massimino accompanies Howard aboard a Soyuz craft on Expedition 31.
Stephen Hawking -- The late, great theoretical physicist Stephen Hawking guest starred a number of times on The Big Bang Theory as himself. After his first appearance, he become a mentor to Sheldon, both personally and professionally.
Bill Nye -- When Professor Proton (Bob Newhart) asks Leonard for advice instead of Sheldon, the latter seeks revenge by rubbing elbows with the "Science Guy" himself, Bill Nye.
Steve Wozniak -- When Sheldon meets—or rather e-meets—"The Great and Powerful Woz" via his own "Shelbot" invention, he asks the Apple co-founder to sign his Apple II computer.
Buzz Aldrin -- While none of the guys actually meet Buzz Aldrin, they do see the legendary astronaut handing out candy to trick-'r-treaters on Halloween in a video.