Astronomy

• Astronomy, study of the universe and the celestial bodies, gas, and dust within it.

• Astronomy includes observations and theories about the solar system, the stars, the galaxies, and the general structure of space.
• Astronomy also includes cosmology, the study of the universe and its past and future.
• People who study astronomy are called astronomers, and they use a wide variety of methods to perform their research.
• These methods usually involve ideas of physics, so most astronomers are also astrophysicists, and the terms astronomer and astrophysicist are basically identical.
• Some areas of astronomy also use techniques of chemistry, geology, and biology.
• Astronomy is the oldest science, dating back thousands of years to when primitive people noticed objects in the sky overhead and watched the way the objects moved.
• In ancient Egypt, the first appearance of certain stars each year marked the onset of the seasonal flood, an important event for agriculture.
• In 17th-century England, astronomy provided methods of keeping track of time that were especially useful for accurate navigation.
• Astronomy has a long tradition of practical results, such as our current understanding of the stars, day and night, the seasons, and the phases of the Moon.
• Much of today's research in astronomy does not address immediate practical problems.
• Instead, it involves basic research to satisfy our curiosity about the universe and the objects in it. One day such knowledge may well be of practical use to humans.