Lectures - Week 1: Introduction to Astronomy - Lecture Help...

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Unformatted text preview: Week 1: Introduction to Astronomy - Lecture Help JavaScript is required for your course. Please ensure JavaScript is enabled in your browser preferences. Print This Page Basic Concepts and Historical Perspective Basics of Science | The Night Sky and Coordinate Systems | Motions in the Sky | Time and Seasons | History of Astronomy Astronomy is an observational science that developed from the beginnings of the human experience, when our ancestors turned their eyes up into the sky during those darkened nights. We are now living in unprecedented times, as we are experiencing an explosion of scientific information our human ancestors could not comprehend, let alone imagine. Spacecraft are visiting the farthest reaches of the solar system, and the space age and information age are in full swing. Digital technology has made such information available to us with just the click of a mouse. In order to more fully appreciate the evolution in the human understanding of the nature of the universe from ancient times to the present, our readings will cover some introductory basics as well as highlight the historical development of the science of Astronomy. Basics of Science When we look anywhere in the Universe, we see evidence of a unity of structure and a unity of behavior. That is, everything in the Universe appears to be made up of the same stuff and follows the same basic physical laws. The ancient Greeks believed that the Earth and heavens were composed of four elements: earth, water, air, and fire. Today we have evidence that the basic structure of matter is the same everywhere in the Universe, as there are about a hundred elements which can form billions of different chemical molecules (or compounds). The rules that govern nature are the same everywhere in the Universe. Keplers laws are simple mathematical rules that correctly describe planetary motion. Galileo developed rules from experiments that describe how objects behave on the Earth. Sir Isaac Newton showed that the observed motion of objects in the sky (Kepler's laws) and the observed behavior of objects near the Earth's surface (Galileo's rules) are both consequences of the same phenomenon, gravity, a fudamental force found in nature. Indeed, Newton did show that Kepler's laws result when gravity is applied to Galileo's rules. There are still gaps and unsolved problems in our understanding of the origin of the Universe, as well as in the evolution of stars. We can apply known physical laws to the conditions of the early Universe, but that will not explain where matter and energy came from in the first place. We will later learn about mysterious dark energy and dark matter that may be present in the Universe. Many hypotheses in science have turned out to be wrong. However, others have been very well tested, for example, gravitation, electricity, and magnetism. Testing is an integral part of any science. We can look at science as an organized method to test nature. Many of us have been introduced to the scientific method, in our first introductions to science, nature....
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This note was uploaded on 12/08/2009 for the course PSYC PSYC110 taught by Professor Forgot during the Spring '08 term at DeVry Chicago.

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Lectures - Week 1: Introduction to Astronomy - Lecture Help...

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