How many days does a cycle mean?

A cycle can have different lengths, depending on the things discussed, specifically: calendar cycle, stock market cycle, four-season cycle, day and night cycle, business cycle, constant week and so on.

1, calendar period

In the calendar, a period is usually one day, starting in the early morning of that day and ending in the early morning of the next day. This period is calculated according to the time required for the earth to rotate once, which is about 24 hours.

2. Stock market cycle

In the stock market, a cycle usually refers to a trading day, from opening to closing. This period is calculated according to the trading time of the exchange, usually a few hours or less.

3. Four seasons cycle

In meteorology and earth science, a cycle usually refers to the four-season cycle, starting in spring and ending in autumn. This period is calculated according to the time required for the earth to make one revolution around the sun, which is about 365.25 days.

4. Circadian cycle

In the study of biological clock and sleep, a cycle usually refers to the cycle of day and night, from sunrise one day to sunrise the next. This period is calculated according to the time required for the earth to rotate once, which is about 24 hours.

5. Business cycle

In economics, cycle usually refers to business cycle or economic cycle, from the beginning of economic expansion to the end of economic recession. This cycle is measured by changes in economic activities and usually takes several years or more.

6. sidereal period

In astronomy, a constant week usually refers to the time required for a star to rotate around the center of the Milky Way. The length of this period is different for different stars, depending on their orbital speed and distance. According to the current observation data, a typical constant week is about 250 million years.