Stephen Hawking opens his book, A Brief History of Time, with the tale of a scientist who lectured confidently on the nature of our solar system and galaxy only to confront a disbeliever at the end of the lecture who had called it all rubbish.
"The world is supported by a giant tortoise."
The scientist, thinking that he could stop this thinking cold, replied, "What is the tortoise standing on?"
The challenger eagerly retorted, "You're very clever, young man, very clever, but it's turtles all the way down!"
The other inspiration for this animation has been the recent efforts in cosmological studies to find out the nature and size of all the dark, unseen matter in the universe. The theory goes that the unltimate answer may determine whether the universe is expanding forever or due to start contracting someday in the distant future.
Could the dark matter be turtles?