Understanding Units of Time II

When it comes to keeping track of time, sometimes larger measurements are needed. Certain characteristics help define these units of time, such as popular decades – like the Sixties. In this article, you will learn more about time measurements, from decades to epochs.

A decade is 10 years and is also called a decennium. Certain decades are defined by crucial moments in history. The 1920s (also known as the Roaring Twenties or the Jazz Age) was characterized by trends that affected the United States, Canada and the United Kingdom. In Europe, the decade was called the “Golden Twenties” because of the economic changes that followed World War I. In the United States, the 1960s were marked by major changes in culture and politics. The hippie movement also took place in the 60s with people wearing bell-bottomed jeans and tie dye clothing.

100 years is called a century, which is comprised of 10 decades. 1,000 years make a millennium, which is also called a chiliad. A bimillennium is comprised of 2,000 years.

An era is a unit used to measure a period of time associated with an important event. An example of an era is the Cenozoic Era, which took place a little over 65 million years ago. The era translated into ‘new life’. By that time, the extinction event that took place at the end of the Cretaceous, where no more non-avian dinosaurs roamed the earth. Eras are also used to measure other periods of time. Religious eras included the Christian, Jewish, and Islamic eras.

Historical periods defined by certain characteristics or trends are also referred to as an era, as seen in the Victorian era and Elizabethan era. Music also played a role in the naming of eras. The Big Band era brought variations in jazz. The style of music that incorporated saxophones, trumpets, and other rhythmic instruments, was popular during the Swing Era , from the early 1930s until the late 1950s. The upbeat music of the Disco Era was influenced by the sounds of funk, Latin, and soul music.

An eon or aeon is a long period of time that usually lasts thousands of years. In geology or astronomy circles, it measures out to one billion years.

A geological era or very long period of time is called an epoch. When used as a reference date, an epoch measures a moment in time associated with a particular era. Astronomers use an epoch to refer to a specific moment in time that represents celestial coordinates or orbital elements. Geologists use an epoch to denote a span of time that is smaller than a “period” yet larger than an “age.”