1 Module Introduction

“I just looked up at a fine twinkling star and thought that a voyager whom I know now many days sail from this coast, might possibly be looking up at that same star with me.”

–Henry David Thoreau
Personal Log Entry c. 840’s

Astronomy is one of the most-fascinating subjects; the Universe in which we live is simply a beautiful and incredible place!

As one of the oldest sciences, astronomy is also one of the fastest-progressing sciences today. In centuries past, people used the stars to tell stories through patterns in the sky. They used the positions of the Sun and Moon to tell time and the seasons, and the positions of the stars to navigate.

With the advent space exploration starting in October 1957, satellites have added to our knowledge of the Universe, from the surface of Mars to the beginning of the Universe itself. It hardly seems a week passes without a new discovery, either from earth-based observations or the myriad of satellites.

Images of the Universe, from galaxies containing billions of stars to the rings of Saturn, inspire both the casual and professional stargazer alike. Astronomy is a passion for many and today is a mainstream hobby, as in years past.

Introduction to Astronomy will provide you with an opportunity to explore both the significant historical aspects of astronomy, as well as contemporary exploration of the Universe. Common topics, such as the phases of the Moon, tides, seasons and the space program, will also be explored.

This module starts with the question, “What is Astronomy?” Simply stated, Astronomy is the study of the Universe. Astronomers classify objects into various groups based on characteristics and locations in our Universe. Some of these classifications, such as stars, are easy to understand scientifically. Other objects are more difficult to classify, and in some instances, to entirely understand. This module identifies basic objects in our Solar System and those beyond, the overall scale of the Universe, and patterns in the night sky.

So welcome to your Universe: a beautiful and incredible place, as you will soon learn.