The UK-China Leonid Meteor Shower Observation Project

3. Why do we only see one side of the Moon?

The Moon is much smaller and lighter than the Earth [it would take 81 moons to balance the Earth]. The Moon has only 1/6 of Earth's gravity, and so the Earth pulls on it more than it pulls on the Earth. Over millions of years, this has slowed down the spin of the Moon, so that it always keeps time with the Earth, and turns round once for every time that it goes round the Earth once. This means that it keeps the same face turned towards us.

Get a friend to sit in a chair, and stand so that you face each other. Walk around your friend, making sure that you keep looking at each other,but also that you can see the wall behind. When you have gone round once, you will have seen the whole room behind your friend, but he or she will only have seen your face.

4. Why do stars that are different sizes seem the same size?

Get hold of a small hand torch and a large powerful torch or a desk lamp. Hold the lamp in a window, and walk some distance away. Have a friend stand close to you with the small torch. Can you arrange it so that the small torch looks brighter than the more powerful light. Faint stars that are close to you, can appear to be as bright or brighter than powerful stars which are much further away.

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