My favorite random facts about our solar system
Although Saturn's rings are hundreds of thousands of miles wide, they are only a couple hundred meters thick.
On one of Neptune's moons there are ice-cliffs so tall it would take 14 minutes to fall off.
The Sun rotates faster around the middle than on other parts. (It's possible because it's made of burning gas.)
A Mercury day is longer than a Mercury year: the planet rotates at a speed so slow that one side of Mercury faces the Sun for about 120 Earth days. During this time, the Sun rises very slowly, then falls back the way it came, and then just before going out of sight, it rises again and continues to go across the sky as it does on Earth, setting in the other direction. Each "day" the Sun rises twice.
As Mars orbits around the Sun it changes the axis on which it spins, creating some mega-weird weather patterns.
If you made a "to scale" model of our solar system with the Sun of diameter 20cm, Pluto would be a dot on a piece of paper about 700 meters away. If you continued the model at this scale and created the whole of the galaxy Milky Way, the star models would continue to be placed passed the actual planet Pluto and further still.
Winds on Neptune go up to 1500 miles per hour.
Neptune's biggest moon, Triton, is gradually nearing Neptune on it's orbit and is due to collide in the next 10 million to 100 million years. When this happens, Neptune will have larger and more rings than Saturn.