"We just had to bring it and

show you," our neighbour told us. She had come over with her older granddaughter, age four.
They had made a trip to what we call "the untidiest shop" in search of some cardboard because granddaughter wanted to make "a sun". They came back with a polystyrene kit to make a model of our solar system instead.
I am not sure how much a reasonably intelligent four year old understands about the solar system. She undoubtedly knows about Earth and the Sun, the Moon and Stars but I think the rest may be just a little confusing.
I say this because I asked whether they had seen the photograph of Earth taken by the Mars Rover. No, they had not seen it. I tried to explain it in the simplest of terms but I don't think the four year old mind could comprehend it - nor did I expect her to understand. She is a child who is firmly rooted in the actual world. She has imagination but the sort of imagination that has to relate to things she knows about.
The Whirlwind or my nephews would have had much more idea at that age - although I am quite sure they would not have really understood either. I can even remember having the idea of the planets explained to me - by my paternal grandfather as we were out on the lawn one night and he was showing me "the Southern Cross". How much did I understand? I don't know. I certainly related the picture in the sky with the picture on the flag and my grandfather explained the rest in the terms of the sun being at the centre of a roundabout and the rest going around it. I remember that clearly so I must have understood something.
But I do wonder what our little visitor understood and what she will understand when they have put the kit together. She has been exposed to a great deal more information about the world than I was or even than my nephews and then the Whirlwind was but, in an odd sort of way, I think she actually knows and understands less. Our little visitor is overloaded with information. She may know but I think she sometimes understands less.