They watch a new world come to life side by side. An alien sunrise. It is breath taking. The Doctor has seen it all before, of course, but never with her. He never gets tired of her child-like wonder at the universe.
"Oh, Doctor, it's so beautiful," she breathes.
The Doctor is not looking at the sunrise. He is looking at her face, upturned and radiant in the growing light.
"Yes, beautiful," he responds.
Her eyes light up and her smile grows.
"It makes you think how small you are, doesn't it?" she asks, not taking her eyes from the scene.
"Maybe not for you. You've traveled all over the place. But for me, the universe feels so large and I feel so small."
"It makes me feel… lonely," the Doctor says.
Rose wraps her arm around his waist, and he puts his around her shoulders.
"Not lonely any more," she insists.
They stand in silence for a long time, watching the sun rise.
"How long will you be staying with me?" he asks, almost afraid of her answer.
"Forever," she replies, leaning her head on his shoulder.
He smiles sadly. She does not know how long forever is.