Copernicus for Five Year Olds

Don't you love it when you have a really good conversation with your kids about Life, The Universe and Everything?
My kids are five and are only three weeks in school, but they seem suddenly to have streaked ahead of where they were a month ago.
Last night in the car on the way home from Grandma's, we started talking about the sky and the clouds and this led on to a truly excellent discussion about day and night, the difference between the sun and the moon, how the world spins on its axis and circles the sun, and how the moon circles the earth. We covered how the sun is actually a big giant star ("yeah we know that mum"), and how stars are hot and the moon is cold; how daytime here is nighttime on the other side of the world, and how a pink sky at night is a shepherd's delight. 
At every point in the discussion it was actually a discussion - everyone joining in, everyone taking turns, and both kids really getting the whole thing, as much as a five-year-old can.

And there were some good questions.

"How did you learn that, mum?"
"I learned it in school."
"How did the teacher learn it?"
"From reading books."
"But how did they learn it, who got the books? How did the first people learn it?"
"Well, a long long time ago...."
"In the olden days?"
"Yes, in the olden days. But the really really old olden days, hundreds of years ago."
"Were you there Mum?" [Inevitable].
"No, sweetie, this is hundreds and hundreds of years ago, a long long long time ago before I was around."
"Where were we? Were we in your tummy?"
[Realising we only have 30 more minutes till we get home, talking a little faster]: "No no, honey, we weren't around. A long long long time ago, in the real olden days..."
"So we was not there, we was nowhere?" [referencing previous conversations on this topic - they don't really get it but they have a frame of reference for it].

"That's right. So in the olden days, so long ago, a smart man figured it out by himself, through looking at the stars and thinking about the earth and day and night and he looked at the sky a lot through his telescope..." [diversion here to explain what a telescope is] "...and he noticed that the stars seem to move around the sky because they're in different places at different times of the night..." [...diversion here to discuss and digest this] ..."and he figured out that actually the stars are not moving but the earth, our planet that we live on, is moving around the sun. Even though you can't feel it and it doesn't feel like we're moving at all. Isn't that amazing?"

"How come only he knew that mum? Didn't other people know that?"
"Well maybe some other people, but most people didn't believe him at first, they thought he was wrong. Until after awhile everyone realised he was right and then they all believed him."
"Did the mans believe him?"
"Yes, some did. Some didn't."
"And did the girls and boys and the womans too?"
[Mental note - interesting order and categorising of people. Must work on that. Sigh - so much to do...]
"Not at first, but in the end, yes most men and women believed him."

Short silence.

"And did YOU believe him mum? In the olden days?"