There are one hundred years in a century. Technically, a century can refer to any period of 100 years, although it is commonly defined as beginning with a year ending in 1 and ending with a year ending in 00 or 100. The 20th century, for instance, began in 1901 and finished in 2000. The twenty-first century started in 2001 and will end in 2100. This time measurement is based on the Gregorian or New Style calendars that the majority of the world currently employs.
Decades
Each century consists of ten decades, or a span of ten years. Like centuries, decades can encompass any 10-year period. On the Gregorian calendar, however, a decade begins with a year ending in 1 and concludes with a year ending in 0. For instance, the decade of the 1990s began in 1991 and concluded in 2000. However, it is more typical for individuals to begin and conclude the year early. The 1990s in this instance began in 1990 and ended in 1999.
Years
Each century and decade is composed of years. A year is a 12-month period beginning on January 1 and ending on December 31. Likewise, each year consists of approximately 365.25 days. However, most individuals believe that a year consists of merely 365 days. Therefore, every four years, these four extra quarters combine to form a year of 366 days. It is known as a leap year. A year is also the amount of time required for the Earth to complete one revolution around the sun.
Months
Each year consists of 12 months. Some months have 31 days, including January, March, May, July, August, October, and December. April, June, September, and November include 30 days each. In a leap year, the month of February consists of 29 days as opposed to its usual 28. The timing of the months was determined by the orbit of the moon.
Days and Weeks
Days are roughly 24-hour intervals that begin at midnight and terminate at 11:59 p.m. each night. Each day is the length of time required for the Earth to rotate on its axis. Each week consists of seven days: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday. Weekend days are Saturday and Sunday, whereas weekdays are Monday through Friday. 52 weeks comprise a year.
Seasons
Spring, summer, autumn, and winter can also be used to mark the passage of time. Based on how the Earth tilts on its axis as it rotates around the sun, the seasons vary. Each season is around three months long. The spring equinox occurs in March, marking the beginning of spring. The summer solstice in June marks the beginning of summer. The autumn equinox occurs in September, marking the beginning of autumn. The winter season begins in December with the winter solstice.
The Gregorian Date System
The majority of modern time measurements are based on the Gregorian calendar, which Pope Gregory XIII made official in 1582. It replaced the Julian calendar, which was discovered to be somewhat off. It was initially adopted by Italy, Poland, Portugal, and Spain. Many Protestant nations were hesitant to utilise it because they believed it was a Catholic plot to stifle their beliefs. England and the colonies that would later comprise the United States accepted it in 1752. It continues to be the most popular calendar.
