did you? But don’t be ashamed. Great and wise men had been living on this earth of ours for thousands of years, and not one of them ever asked that question until about two hundred and fifty years ago.
One day Isaac Newton, a young man of twenty-three, who had just been graduated from Cambridge University, England, was sitting in the garden of his father’s house when he saw an apple fall. "Now, what made that apple fall?" he asked himself. Very likely he remembered that the great astronomer, Galileo, had proved that a one pound and a ten pound cannon ball, dropped together from the same height, struck the earth at the same instant. So weight had nothing to do with the falling. Then, perhaps, it was because the earth pulled unsupported objects toward itself. But if the earth's pull was all there was to it, the heavier the object the faster it should fall. The falling object must also pull back. In order to pull down the heavier object, the earth must have to pull harder to overcome the stronger back pull. Everything in space must pull and be pulled, he thought, by other bodies.
But why didn’t the moon fall to the earth and the earth fall into the sun, if this was so? This young man had made a great name for himself in mathematics in his college. Now he began to do sums in algebra using, for starting figures, the distance from the surface to the center of the earth, the sizes and distances of the sun and moon, and many other known measurements. Finally, he calculated, the pulling power must become weaker, as the distance between two bodies became greater. And the pulling-back power increases with the size of the object. At some point he thought these two powers must equal each other, and keep bodies suspended, unable to fall or to get away. This explained why the earth and other planets did not fall into the sun; why the smaller planets were nearest the sun; why the moon did not fall to the earth, and why all the heavenly bodies kept their places circling around the sun, and couldn't go wandering off and bumping into each other.
So the whole science of astronomy was overturned, because a college boy in a quiet country garden asked that "foolish" question about an apple, and spent years and years in working out the answer. (See Gravity, Newton.)
WHAT IS AN ECLIPSE?
Do you know the poem: "I have a little shadow that follows after me?" The little boy's shadow puzzled him. If he had only
