I said gravity holds us on, I was speculating as to what keeps the comet together since it has little gravity and no spin (as far as I know) to create gravity as is done in a spaceship to create artificial gravity.
Spinning spaceships creates artificial gravity by using centrifugal force to keep the contents stuck to the inside of the outer wall, like some amusement-park rides.
Keep in mind also that “artificial gravity by spinning” kept many an unfortunate B-17 crewman stuck to the inside of his airplane after a wing had been blown off.