William Bly, age 9, of Geneseo Rd for his question:
How much does the moon weigh?
The golden moon looks about as big as a pumpkin, but this is because it is such a long, long way away. Faraway things look smaller. Actually the moon is a whopper and we would need a monstrous pair of scales to weigh it. We would have to take its weight in tons and the number of tons is so big that we would have to think hard. in order to grasp it.
Suppose we had such a. big pair of scales and then suppose we could make the moon sit on them long enough to be weighed. The needle would awing around until just short of 800 quintillion tons. This is the weight of the moon. In figures it is eight followed by 20 zeros. Now lets compare that weight with the weight of the earth, which is our world and everything in it. Let’s put the earth on our make believe scales and guess how many moons we would need to balance it.
The earth side of the scales goes down with a bang, for the earth is much, much heavier than the moons Lets add 20, 40, 60 moons. They still do not equal the weight of the earth. But when we add 83 moons, the two sides of the scales are fairly equally balanced. The moon weighs almost 800 quintillion tons but the earth weighs 83 times more than the moon.
You might guess that the earth is also 83 times larger than the moon. But this is not so at all. The diameter of the moon is a straight line through the middle from side to side. The earth’s diameter is only about four times longer than the moon’s. If they were flat pennies side by side, the earth would be only about four times bigger than the moon.
The size of the moon is the actual space it takes up in the sky. This is called its volume, Is its volume 83 times less than the earth’s or one quarter? It is neither.
The volume of the earth is 50 times greater than the moon’s. This means that if the earth were hollow and very hungry, it could swallow 50 moons,
The differences in size, weight and diameter seem very confusing to us. But they tell the experts a lot of facts about the moon. The moon weighs less for its size. It is more bulky than the earth. A bag of feathers weighs less than a bag of coal of the same size. This, as everyone knows, is because feathers are bulkier than coal. In coal, the material is jam packed close tog ether’ tight and solid. In feathers, the airy fairy material is loosely packed. We say that coal is denser than feathers.
The moon, of course, is not stuffed with feathers, But the material inside it is not so heavy as the material inside the earth. In our globe, the outer layer is made of light rocky material. Heavier layers are underneath it. In the center is a huge round ball of very heavy metals. The moon, we think, has no such heavy core in the middle. It seems to be made from materials just about as heavy as the rocks in the earths crust.