“I’m going to put this in a lead box and take it away now.”
Turns out it wasn’t just an active set… but a radioactive one.
Many scientists even say the serieshelped make subjects like physics and astronomy cool.

Simon Helberg, Melissa Rauch, Kunal Nayyar, Mayim Bialik, Jim Parsons, Johnny Galecki, and Kaley Cuoco on ‘The Big Bang Theory’.Michael Yarish/CBS
It became so famous in the scientific community that many notable figures stopped by the sitcom’s set.
“He’d just come by and hang out.”
During one shoot, a famed physicist stopped by… and noticed something a little peculiar.
“One day this super famous physicist was visiting,” co-creator Bill Prady says.
During the tour, the physicist noticed one of the props in Leonard and Sheldon’s apartment.
The physicist looks at it and goes, ‘That’s an old Geiger counter.'"
(A Geiger counter is a machine used to detect radiation).
It turns out the Geiger counter was more than just a unique prop.
I wonder if there’s uranium in that.'"
“It’s sorta like a class-action suit waiting to happen,” Lorre says with a laugh.