It's the 21st CENTURY.
The Big Bang Theory Season 5, Episode 17
...was a third CENTURY Roman priest
who was stoned and beheaded...
The Big Bang Theory Season 3, Episode 15
Why don't you have computers
and shit? It's the 20th CENTURY.
Breaking Bad Season 2, Episode 12
Bosoms would not have said, "Howdy,"
in the 15th CENTURY.
The Big Bang Theory Season 2, Episode 2
...to function in 18th CENTURY Vienna.
The Big Bang Theory Season 4, Episode 21