My favorite explanation of the unknown is the oft-repeated anecdote from Stephen Hawking. A scientist giving a lecture on astronomy is challenged by an old lady. "The world is really a flat plate supported on the back of a giant tortoise," she says.
The bemused scientist replies, "But what is the tortoise standing on?"
"You're very clever, young man, very clever,"
says the old lady. "But it's turtles all the way down."
That's good enough for me.