The Centre of the Universe

A young one asked an old one how to get to the centre of the universe.
"It's an awfully big place. How do I get there? How will I know I've arrived?"
"Look inside."
"I'm not the Universe."
"Yes, you are."
"It is impossible," said the young one.
"As long as you believe that you will never find it."
This answer was not good enough. It confused the young one who was used to concrete examples, boundaries, and measures.
"Very well," said the old one. "This is what you do. Find a tree. Sit at its root and lean back against it. Close your eyes.  Follow your feelings into the tree."
The young one looked doubtful, but at least this answered offered a tangible exercise.
"And then what do I do?"
"Invite the tree into you."
"Absurd," declared the young one. "How can a tree get inside of me?"
The wise elder smiled. "Go ask the tree."