Foreward

How exciting it is to live in the age of space exploration! While telescopes probe the far reaches of the Universe, artificial satellites observe the Sun and nearby space. Orbiting instruments send back information about the planets. Astronauts have reached and explored our neighbor world, the Moon. Because the lunar sky is always perfectly clear and black, even in daytime, the Moon will be a good Place for an observatory. Astronomers aim to place telescopes there for studying the stars, especially our own star, the Sun. The Sun continually shoots vast clouds of atoms into space. Sometimes these clouds collide with the Earth and become trapped in its magnetic field. Occasionally atoms spill into the Earth's atmosphere around the poles, setting the air aglow with the northern and southern lights. The speeding particles may be dangerous to astronauts. For this and other reasons, scientists are carefully investigating the Sun's activity. Each of the planets circling the Sun has its own interesting features. Bright Venus changes shape like the Moon. Clouds always hide its solid surface, but radio waves from deep in Venus' atmosphere give some information about the planet's surface. It is very hot, perhaps with a temperature of 800 degrees Fahrenheit. At the other extreme are the cold giants, Jupiter and Saturn. Saturn is the planet with the beautiful rings. Jupiter has many moons, four of which are large and bright enough to be seen with a small telescope or binocular. The planet Mars is a tempting world for future astronauts to visit. They will find the answers to many questions. Are those mysterious grey-green areas some form of plant life? Do any animals exist on Mars? Astronomers generally agree that Mars, of all the planets of the solar system, is the one most likely to sustain life. At night we see thousands of stars in the sky. These stars are suns, some of them larger and brighter than our Sun. The stars seem small and faint only because they are so very far away. In addition to the stars that we can see with the unaided eye, there are perhaps a hundred thousand million more. Through a telescope the hazy glow of the Milky Way becomes rich pattern of stars. In these pages you will read of the many wonders of the heavens. You will learn how astronomers today are adding to the knowl edge gained by sky watchers of the past. Read the great story of astronomy, but also do more than read. Become a sky watcher yourself. When the night is dark and clear, go out of doors and become acquainted with the stars. Make the constellations your friends. I am sure you will find the study of astrononly a great and exciting adventure. As you explore the sky, you follow in the footsteps of the men and women who have observed its wonders in the past. You join the company of the astronomers Wh0 are probing its mysteries today.