A Few Words about our Oldest Science

Astronomy is one of those subjects that just reaches out and grabs you the first time you step outside under a sky full of stars. Sure, its a science, but astronomy is also a cultural practice. People have watched the skies since the first person looked up and wondered about what was up there. Once they got the hang of observing and noticing what was happening in the sky, it wasnt long before people figured out a way to use the sky as a calendar for planting, growing, harvesting, and hunting. It aided in survival.   Noticing Sky Cycles It didnt take long for observers to notice that the Sun rises in the east and sets in the west. Or, that the Moon moves through a monthly cycle of phases. Or, that certain spots of light in the sky move against the backdrop of stars (which appear to twinkle due to the action of Earths atmosphere).. Those wanderers, which look more disk-like, became known as planets, after the Greek word planetes. From Earth, with the naked eye, you can seeMercury, Venus, Mars, Jupiter, and Saturn. The others require a telescope, and are quite faint. The point is, these are things you can see for yourself.   Oh, and you can also see the Moon, which is one of the easiest objects to observe. Study its mottled surface and it will show you evidence of ancient (and recent) bombardments. Did you know that the Moon was created when Earth and another object collided early in solar system history? And, if we didnt have a moon, there might not be life on Earth?   Thats a fascinating aspect of astronomy that most of us dont think about! Star Patterns Help you Navigate the Sky If you watch the sky a few nights in a row, youll notice star patterns. Stars are more or less randomly arranged in three-dimensional  space, but from our point of view on Earth, they appear in patterns called constellations. The Northern Cross, also known as Cygnus the Swan, is one such pattern. So is Ursa Major, which contains the Big Dipper, and the constellation Crux in the Southern Hemisphere skies. While those are merely a trick of perspective, those patterns help us make our way around the sky. They add order to an otherwise chaotic-seeming universe. You Can Do Astronomy You dont need much to do astronomy: just your eyes and a good dark sky sight. Oh, you can add in binoculars, or a telescope to help magnify your view, but they arent necessary when youre getting started. For thousands of years, people did astronomy without any fancy equipment at all.   The science of astronomy began as   people went out and observed each night and made notes of what they saw. In time, they DID build telescopes, and eventually attached cameras to them, to record what they saw. Today, astronomers use the light (emissions) from objects in space to understand a great deal about those objects (including their temperatures and motions in space). To do this, they  use ground-based AND space-based observatories to study the far distant reaches of the universe. Astronomy concerns itself with studying and explaining everything from nearby planets to the earliest galaxies that formed not long after the universe was born, some 13.8 billion years ago.   Making Astronomy a Career To do Big Astronomy, people need a solid background in math and physics, but they still need a basic familiarity with the sky. They need to know what stars and planets are, and what galaxies and nebulae look like. So, in the end, it all still comes down to that basic activity of going out and looking up. And, if you get hooked, you can take it at your own speed, learning the constellations, the names and motions of the planets, and eventually peering out to deep space with your own telescope and binoculars.   Deep down, were all astronomers and were descended from astronomers. So, when you go out tonight and look up, think about this: youre carrying on a tradition as old as humanity. Where you go from there — well, the skys the limit!