Want to stay on top of all the space news? Follow @universetoday on TwitterThere are many answers to ”What is astronomy?”. The long versions of which differ in a few ways, but are basically the same. In its most basic sense astronomy is the study of everything in the universe. In particular it is the study of the motions and natures of celestial bodies including, but not limited to, planets, stars, and galaxies. Because of its wide scope of study astronomy is broken down into many different specialties and is based on other disciplines like mathematics, chemistry, geology, biology, and physics. Physics is heavily relied on, so much so that many astronomers are also referred to as astrophysicists.
Astronomy is an ever evolving and improving science. It is the oldest science in the world. Early cultures performed methodical observations of the night sky to decide when to plant and what the best day was for a celebration. The invention of the telescope propelled astronomy into a modern science, before that it was mostly theory and astrology combined. In modern times, the field of astronomy has split into observational and theoretical branches. Observational astronomy is focused on acquiring data from observations of celestial objects, which is then analyzed using basic principles of physics. Theoretical astronomy is oriented towards the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain the observational results, and observations being used to confirm theoretical results.
Astronomy is one of the few fields of science where amateurs have contributed as many new discoveries as the professionals have. That trend is still quite encouraged. Many contributions in the discovery and observation of transient phenomena originate from the average guy with a telescope and a fistful of enthusiasm. There are even books devoted to telling amateur astronomers how to get professional attention as well as how to get published.
In order to understand what astronomy is you would have to read about all of the different fields within the science. I can’t provide you all of that information, but you can start here. Here on Universe Today we have several great articles: here is one about astrobiology, here is another about submillimeter astronomy, and a third about radio astronomy. Not to be outdone, Astronomy Cast offers a couple of good episodes on the topic. One is about basic astronomy(movement and positions in the solar system) and another about one of the goals of astronomy: finding other worlds.