Rosh Hashanah 2: Keeping Track of Time

Some introduction to Rosh Hashanah, and why we mark time. The term "Rosh Hashanah," meaning the head of the year, is not really used in the Bible, yet in the rabbinic literature, there are 4 "new years." Some time is marked by astronomy (and math) - imposing structure from the outside - and others are based on the physical reality of growth and development. Diving in to the first mishnah, we find 4 different heads of the year to mark time counting different things. The first of Nisan and the first of Tishrei get the most attention, but the first of Elul and Shevat (or the 15th) also count. All of which have practical implications, especially for matters of tithing. Plus, how do we count from the time of the exodus from Egypt? And what does it mean that the world was created in the middle of the year?