““You’re not very religious, are you?” said Irene.
“I’m more into gravity.””

“You’re beautiful because when you were born, undiscovered planets lined up to peep over the rim of your cradle and lay gifts of gravity and light at your miniature feet”

“The most profound joy has more of gravity than of gaiety in it.”

“Ender understood more than she said. Manipulation of gravity was one thing; deception by the officers was another; but the most important message was this: the adults are the enemy, not the other armies. They do not tell us the truth.”

“If gravity is a fundamental force, then it has to be explained by an expanded version of general relativity, a more complete, a more fundamental theory. Whether that is quantum gravity of something more radical that requires a paradigm shift like, for instance, our research in multiverse theory, nobody knows at the moment.”

“Power is like matter, it has gravity, it clumps and then starts to draw more into itself.”

“The light works," he said, indicating the window, "the gravity works," he said, dropping a pencil on the floor. "Anything else we have to take our chances with.”

“You know that the law of gravity will kill you when you jump.”

“As regards very small celestial bodies of a light-minded nature, the law of levity is allowed to supersede the law of gravity.”

“Khouri did not need to be told that Hades was a neutron star, any more than she needed to be told that there was no such thing as a safe close encounter with one. You either kept away or you died; those were the rules, and there was no force in the universe capable of negating them. Gravity ruled, and gravity did not take into account circumstances, or the unfairness of things, or listen to eleventh-hour petitions before reluctantly repealing its laws. Gravity crushed, and near the surface of a neutron star gravity crushed absolutely, until diamond flowed like water; until a mountain collapsed into a millionth of its height.”