
And, of course, it's Gravity Probe B.
The Big Bang Theory Season 1, Episode 13

Unless you have Gravity
on Blu-ray under that skirt,
The Big Bang Theory Season 7, Episode 21

What about loop quantum GRAVITY?
The Big Bang Theory Season 7, Episode 20

...for this university's
six-loop quantum GRAVITY calculations.
The Big Bang Theory Season 6, Episode 9

Loop quantum GRAVITY
is the future of physics.
The Big Bang Theory Season 2, Episode 2