David Beverly, age 11, of Richmond, Va.,
Why does the moon look as big as the sun?
The golden moon rolls on an orbit around and around the earth and, once in a great while, it gets directly between us and the sun, Then we have a total solar eclipse. For maybe seven minutes, the dazzling face of the sun is completely blotted out by the moon. This can happen only at the time of the new moon, when the sun is shining on the far side of the moon and, for a brief spell, all the sunlight is shut off from the earth. Even at noon there is darkness and the stars appear in the sky.
A total solar eclipse occurs only once in a while and is seen from only a small part of the earth’s surface. On July 20, 1963, this dramatic spectacle may be seen from northern New England and parts of Canada. If the sky is clear, the lucky observers will see the dark disk of the moon exactly cover the radiant face of the sun. This looks for all the world like positive proof that the moon and the sun are exactly the same size.
Naturally, we know that this is not so, The moon is much closer to us than the sun and faraway things tend to look smaller. A distant mountain pokes up like a dim pile of dirt above the horizon, but as we get nearer, it towers above our heads, The heavenly bodies in the sky also diminish with distance. The moon looks as big as the sun only because it is closer to us. Seen from the planet Venus, the sun would appear much bigger than it does from the earth and our moon, if it could be seen at all, would be very tiny.
Our eyes are so used to the fact that faraway things look smaller that we allow for it when we look at the landscape. There is a ratio in this shrinkage and at a certain distance an object looks half its proper size. At this distance, it looks the same size as an object only half its size.
In the wide reaches of the sky, however, our eyes do not allow for this distance shrinkage, A star seen as a pin point may be bigger than the sun, while the sun and the moon seem to be exactly the same size.
The diameter of the moon is 2160 miles. The diameter of the gun is about 860,000 miles ‑ which means that the face of the sun is about 400 times wider than the face of the moon. The average distance of the moon is only 238,000 miles while the sun is more than 92 million miles away from us. Just by chance, the sun happens to be about 400 times bigger than the moon and also about 400 times farther away from us. This is why they look exactly the same size.
The planets also shrink with distance and fool the eye. Our neighbors, Venus and Mars, at times seem to be the biggest and brightest of the planets. They outshine Jupiter at his brightest and make Saturn seem small and dim. Yet Saturn could swallow both Mars and Venus and giant Jupiter could swallow all the other planets of the Solar System.