The closest astronomical body to ourselves is the Earth upon which we live. In all the thousands of years man has been civilized, he has been trying to increase his knowledge of this world, that is his home. This is the story of those efforts; of the long struggle to show that the Earth is round and that it rotates on its axis. Although the ancient Greeks advanced this theory, it wasn’t until the early Sixteenth Century that the voyage of Magellan demonstrated the fact of roundness and finally showed the true size of our planet. Not until the Nineteenth Century was there a final proof that our Earth rotates.
Even after the roundness of the Earth was established, the exact nature of the roundness was in dispute. Did the Earth bulge at the equator or at the poles? How could one tell? And if it bulged, was the bulge exactly even? As late as 1958, the use of artificial satellites introduced astounding new information about the exact shape of the Earth.
Nor is the Earth alone in space. Accompanying it on its travels through long eons, is a companion world, the Moon. The Moon is one of the largest satellites in the entire Solar System, over one-quarter the diameter of the world about which is circles. From far out in space, the Earth and the Moon would seem two planets, rather than a planet and a satellite; in fact, a double planet. Slowly, beginning with the invention of the telescope in the Seventeenth Century, man learned to know the face and some of the facts of Earth’s faithful companion.
In this book, Isaac Asimov tells, with his usual skill and clarity, the fascinating story of how man has probed the secrets of Earth and Moon. He carries the story form ancient times to this very moment, when we are on the point of reaching a new climax by actually landing on the Moon, the other half of–the double planet.
This is one of the last of the Abelard-Schuman science juveniles, and although it is entertaining and interesting enough, it does not stand out quite as much as do some of the others.
In part, this is because there are a number of astronomy books which Asimov wrote later on which cover some of the same ground. None, of course, are on the earth-moon system as a whole, but virtually everything that Asimov says here is said elsewhere, and generally rather better. And, of course, the book suffers from being badly dated, as do many of the early science books. Written nearly a decade before Apollo 11, its glimpses of the future of manned space flight turn out to have been embarrassingly off.
Still, all that aside it’s not a bad book and rather enjoyable. It tends to be a little statistic heavy, but it covers much of the basics of the physical nature of the earth and the moon and so includes astronomy, seismology, meteorology, physics, and so on. It may be on the weak side—but not really by much.