Dear Mr. Dawkins,
I'd like to tell you a fairy tale, since you like fairy tales.
Once upon a time, about 15 to 20 billion years ago, there was nothing; absolutely nothing anywhere in the entire universe.
Then the nothing exploded! A total vacuum, so they tell us, had become something!
After the explosion occurred, the law of gravity is supposed to have invented itself, which is quite a thought. Soon the complete formulas of other laws began inventing themselves.
"The naive view implies that the universe suddenly came into existence and found a complete system of physical laws waiting to be obeyed . . Actually it seems more natural to suppose that the physical universe and the laws of physics are interdependent." —*WH. McCrea, "Cosmology after Half a Century," Science, Vol. 160, June 1968, p. 1297.
At some point (theories vary as to when) as temperatures cooled, the nothingness magically turned itself into hydrogen! Then, at some point immediately or thereafter (opinions vary), some of the hydrogen changed into helium.
Both hydrogen and helium are gases. We are told that the gas spread outward throughout the universe for about ten billion years, and contrary to the laws of physics, the hydrogen and helium gas gradually pushed itself into chunks. More and more of it clumped together, until soon gigantic pieces of it had formed. These became stars and galaxies with their intricate orbits.
The initial "Bang" explosion is said to have produced only hydrogen and perhaps helium, but after the stars had pushed themselves together they began exploding like strings of firecrackers. Then, reforming, large numbers exploded a second time. And presto! All 90 elements had been produced by the second wave of explosions!
As the fairy tale goes on, explosion after explosion took place as loose gas pressed itself into stars and then those stars exploded. Hundreds of billions of stars were exploding all over the universe. This went on for long ages. There was no reason why it started, and there was no way for it to stop. It was a self-initiating activity, destined to continue on forever. These regularly occurring explosions should be occurring in our own time. When you go out tonight you ought to be able to see exploding stars in the sky.
Each time these stars exploded outward, they gathered back together and exploded again. We are told that our own sun had its third explosion about 5 billion years ago.
But, quite well aware that stars are not now regularly exploding in the sky, the theorists came up with the idea that about a million years ago the explosions mysteriously stopped! Why did they set that terminal date at "a million years ago"? Because the most distant stars were thought to be a million light years away, and since they are not now seen to be exploding it was decided that they must have stopped exploding just before the time that their starlight was sent to us from that those farthest distances from Earth.
End of story and the theorists lived happily ever after.
George Lemaitre, a Belgium Jesuit, struck on the basic idea in 1927, and George Gamow, R.A. Alpher, and R. Herman devised the basic Big Bang model in 1948-1949. But it was Gamow, a well-known Reasearch scientist and science fiction writer, that gave it its present name and popularized it after that. Gamow dubbed it the "Big Bang." Campaigning for the idea enthusiastically, he was able to convince many other scientists. Because Gamow was also a part-time science-fiction writer, he enjoyed writing about impossible things.
So when it came to explaining the "Big Bang" theory to fellow scientists, he used quaint little cartoons to emphasize the details. The cartoons really helped sell the idea.