This picture perfectly sums up a conversation that I overheard yesterday between Miss A (5) and Miss M (just 3):

Miss A:  Poor Pluto.  It's a planet!  Not a asteroid.
Miss M:  Oh.  I thought we were going there too.
Miss A:  No!  It's way up in outer space!  There's like lots of planets!

And then...

Miss A:  Trees can't grow to outer space only rocket ships are fast enough.
Miss M:  Cars do that too.
Miss A:  No they don't.
Miss M:  Some times they do, some times they can't, but sometimes they do.
Miss M:  Blue galaxies are just for me.  I love blue galaxies.  They are sparkly.
Miss A:  Mama did you know that Pluto is a sun?
Mama:  No it isn't.
Miss A:  Oh, it's just a planet.
Miss M:  Jupider has suns, but it doesn't have suns, but it does...
Miss M:  Outer space lives in Virginia.  It doesn't have Floppsies or anything.

(Silence in the car while heavy thinking is going on...)

Miss A:  Earthquakes happened in Virginia.
Miss M:  Volcanoes live in Virginia.

Miss M:  Galaxies turn into Floppsies again.  Galaxies have lights and they don't and galaxies have poison and they don't.