Los Angeles — In the life of the universe, 12 years is nothing. In the life of a network sitcom, it's an eternity.

With 279 episodes, "The Big Bang Theory" is one of the longest running comedies in TV history, and the most-watched, earning 52 Emmy nominations. That's really saying something for a show that geeked out over topics like string theory, and quantum brain dynamics.

It made nerdy cool, even romantic. But it doesn't take a rocket scientist to know that nothing lasts forever.

The show wasn't cheap. Its main cast each made around $1 million an episode and Jim Parsons, who won four Emmys for his role as Sheldon Cooper, had decided to move on.

None of that made the goodbyes easier during the final taping earlier this month.

"There was just a synergy there. Whatever that elusive chemistry you create, it was, it was just there," said "The Big Bang Theory" actor Johnny Galecki.



Exactly how it will end is closely guarded secret. Maybe that elevator will finally be fixed.

Whatever happens, it's fair to say much like a comet, "The Big Bang Theory" will keep hurdling through space in syndication for years.

Watch the series finale of "The Big Bang Theory" Thursday, May 16, in two back-to-back episodes starting at 8 p.m. ET/7 p.m. CT on CBS. At 9:30 p.m. ET/ 8:30 p.m. CT, Cuoco and Galecki will host the special retrospective, "Unraveling the Mystery: A Big Bang Farewell."