Some Important Physical Fundamentals

The first chapter deals with physical fundamentals that will be incorporated at several points into the later treatment of astrophysics. We familiarize ourselves with the various time and space scales. Since they cover many orders of magnitude, quite different models are necessary. In many cases, a classical description is still appropriate, but we often encounter its limits and must calculate quantum mechanically. Electromagnetic radiation currently provides us with the essential information from distant objects. Therefore, it is advisable to summarize our knowledge of radiation transport very early on.