“Balance. It was all about balance. That had been one of the first things that she had learned: the centre of the seesaw has neither up nor down, but upness and downness flow through it while it remains unmoved. You had to be the centre of the seesaw so the pain flowed through you, not into you. It was very hard. But she could do it!”

“There is nothing particularly special about that location of the centre of mass. If you were to find yourself at the precise spot that is the centre of mass of the earth-moon system, the only thing unusual that you would notice is that there would be one thousand miles of rock on top of your head.Pluto is only about twice the size of Charon, so if you put Pluto and Charon on the cosmic seesaw you would find that the balance point is a little bit outside Pluto, rather than inside it. Again, there is nothing particularly special going on there. If you were to find yourself at that precise spot, you would only notice that you were very, very cold and could no longer breathe.”

“I've heard people talk about the circle of life. What comes around goes around and other such contiguous descriptions. But I think life is a seesaw, the kind that used to populate every children's playground. Seesaws rarely balance. They're usually in motion, either flinging you up or dropping you down. They can be fun or they can be terrifying - a lot of it depends on the other person.”

“Quietly they moved down the calm and sacred river that had come down to earth so that its waters might flow over the ashes of those long dead, and that would continue to flow long after the human race had, through hatred and knowledge, burned itself out.”

“In a single week I had lost the two most important men in my life. Yet the word “lost” was misleading. Neither had died and it had been years since either had played any outwardly discernible role in my life. Internally, however, they have been pivotal, at the centre of everything. Now that centre, my centre, had slipped.”

“He pulled her back, off balance so that she fell against him, and he took her face in his two hands and held it very still while his eyes looked down into hers. Somber, truthful, painfully honest. "I love you, Chloe," he said. "Which is the most dangerous thing I could do.”