Astronomy & Science Archive
There’s a whole lot more to the Solar System than you learned from good old Mrs. Magillicuddy teaching science class back in the early school days. People used to think of it as just a simply vast place, consisting of nothing more than the Sun surrounded placidly by its nine revolving planets
The Moon has been revolving around the Earth for about 4.5 billion years, and it’s one-quarter the size of our planet. Its innermost core is made up of iron, nickel, and sulfur. The two outer layers comprise a real potpourri of materials: The middle layer mostly contains olivine, orthopyroxene, and clinopyroxine. The
Throughout history people have felt an inexorable draw to the Sun, an irresistible compulsion to set our clocks by its rays, and to honor it as the center of the universe. When you realize that the Sun makes up 99 percent of all matter in the solar system, it becomes quite understandable.
Most people think of NASA’s space shuttle program as the entire manned space flight programs including Mercury, Gemini, and Apollo flights. In fact, the use of the shuttle did not begin until 1981—well after those programs ended. While the earlier chapters in America’s flight program included manned spacecraft, the shuttle program was