
Previously on
The Big Bang Theory...
The Big Bang Theory Season 11, Episode 15

Um, it used to be string THEORY,
now it's dark matter.
The Big Bang Theory Season 9, Episode 8

There was a scientist who had a THEORY
And James Clerk Maxwell was his name-o
The Big Bang Theory Season 8, Episode 21

Previously on
The Big Bang Theory...
The Big Bang Theory Season 7, Episode 10