This is based on the Astronomy Course Barry taught to juniors and seniors in high school. Internal links will be to help people remember definitions of terms and link to extra explanations. Please feel free to email any questions to us at any time. This course will be divided into two main parts. The first will include basic data -- what it is we see 'out there.' The second part will include explanations and interpretations.
Our suggestion for any instructors is that you do not do anything except "The Data -- What We See Out There" for grades below about ten or eleven. Chemistry, Two Models, and The Explanations would probably be best held off for later high school, college, and adult.
Because this is an online course, we will be able to keep up with new developments in astronomy as they occur. One of the major problems textbooks have is that they cannot do that. As a result, there may even be changes in sections sometimes. We will try to mark them clearly when they occur. Basic updates will be at the bottom of relevant pages with the dates in bold print.
We have not suggested any tests or quizzes to be given with this as it is up to the individual instructor to decide how much material he or she wants to present and when.
People have been interested in the stars for as long as we know. Astronomy and astrology were one field of study for a very long time, and there may be a very good reason for this as this article explores.
For most of human history, people could only see what their own eyes could see in the night sky. However all that changed in 1608 with the earliest working telescope. This telescope is credited to Hans Lippershey. Galileo used the design the following year, and in 1611, Johannes Kepler suggested improvements.
It is difficult to say when astronomy and astrology parted company. Crediting the formation of star groups to various gods and goddesses with whom they were associated started quite early and still appears to be part of some religions today. The two fields only gradually separated in the West in the 17th Century with the Age of Reason. They have come to be regarded as completely separate only since the 18th Century, around the time of Newton. At that time, Newton was formulating the laws of gravity. It was assumed then that gravity was the force responsible for everything in the universe. The moon around the earth, the earth around the sun, the planets around the sun -- everything we could see appeared to be gravitationally controlled. Therefore it was presumed that the entire universe was this way.
This is still the primary thought among most astronomers and astrophysicists today: gravity is considered responsible for galaxy and star formation and maintenance.
However in the past twenty years, this has been challenged for several reasons. First, gravity is a weak force and in order to accomodate that, some fancy mathematics and inventions have had to be employed to answer for what is seen in space. In addition, the discovery that massive electric currents and magnetic fields are present in space has caused a number of physicists to consider the electromagnetic approach to astronomy instead of a gravitational approach.
While the gravitational approach is still being taught in most places of learning, we will concentrate here on the electromagnetic approach, which we feel is a far more satisfactory explanation of what we see through our telescopes and in accord with the information sent back to earth from space probes.