A well-known scientist (some say it was Bertrand Russell) once
gave a public lecture on astronomy. he described how the earth
orbits around the sun and how the sun, in turn, orbits around
the center of a vast collection of stars called our galaxy. At
the end of the lecture, a little old lady at the back of the
room got up and said "What you have told us is rubbish. The
world is really a flat plate supported on the back of a giant
totroise." The scientist gave a superior smile before replying,
"What is the tortoise standing on?" "You're a very clever, young
man, very clever," said the old lady. "But it's turtles all the
way down!"

    - Taken from
    "A Brief History of Time: From The Big Bang
    to Black Holes" by Stephen W. Hawking

