How is time defined? How is time divided?

Time is a measure of the process of motion, specifically, the measurement of the process of motion that can be carried out by counting the period of motion.

Time has the following characteristics:

1. Specific time unit.

Each corresponds to a particular period of motion. For example, the year, month, and day correspond to the Earth's cycle around the Sun and the Moon, respectively.

The period of revolution around the Earth and the rotation of the Earth.

cycles. The number of years, months, and days is counted for the corresponding periods of movement.

2. Since the counting of the exercise cycle is carried out in the order from small to large, what has been counted is the past, what is being counted is the present, and what has not been counted is the future. Thus, time is one-way and irreversible in the past, present, and future.

3. Since the retrospection or counting of cycles moving in both the past and present directions is continuous and infinite, time is also continuous and infinite. In other words, time has neither a beginning nor an end.

4. The method of measuring time is as follows:

The motion period of a particular object is selected as the reference of time, and the process of other motions is measured by counting this continuous motion cycle. That is, a special periodic motion process is used to measure other motion processes. This particular periodic motion can be considered as a temporal reference.

5. Time is not absolute but relative. This is because the special periodic motion chosen as the temporal reference is affected by other factors, and the movement period is not absolutely constant between them. For example, precise measurements indicate:

The cycles of years, months, and days are constantly changing, sometimes faster, sometimes slower, and the general trend is getting longer. The variation between them is also disproportionate.

In particular, each specific object has a certain lifespan, no matter how long it lives. If the object that is a reference of some kind of time disappears. Then this specific periodic movement does not exist at all.

We had to choose a new time benchmark. Therefore, there is no such thing as an absolutely immutable motion, and an absolutely precise and eternal clock does not exist, Newton.

Absolute time also does not exist.

6. Space is a measure of the size and orientation of a substance, the measurement method is to use a ruler, time is the measurement of the movement process, and the measurement method is to use a clock. Any clock consists of a periodic motion and a counting mechanism for that period. Therefore, it must be emphasized once again that time and space have no relationship.

7. Space and time.

It is a measure of which is finite in scope in any historical period, but it does not affect the infinity of space, large and small, nor the infinity of time, past and future. At the same time, the argument that space-time is bent is incomprehensible and absurd. <>

Definition of time: The concept of time summarized by human beings in life comes from the sequence of events in daily life. Of course, what people get in life is not only the idea of the order of events, but also the concept of the length of time interval, which is based on the comparison of two processes - for example, two things start at the same time, but one thing ends and the other thing is still going on, so we say that the other thing takes longer.

Here we can see that people use measurable processes to measure abstract time.

Similarly in physics, time is defined by physical processes, first in a frame of reference (it is required to be an inertial frame, or a non-inertial frame, but the spatial range of the process is infinitely small), a physical process is determined, it is set as a unit of time, and then this process is compared with other processes to determine time. <>

The 24 regions of the earth's surface divided by meridians. When we see the sun rise in Shanghai, it takes another half an hour for those living in Singapore to see the sun rise. Residents of London, England, are still asleep and will not see the sun for another eight hours.

People from all over the world live and work in their own local areas, which will bring a lot of inconvenience and difficulties to daily life and transportation. In order to take care of the convenience of each region, it is easy for people in other places to convert local time to other places. The international conference decided to divide the earth's surface into regions from south to north according to the meridians, and to stipulate a time difference of one hour in adjacent areas.

People at the eastern and western ends of the same area see the sun rise at most 1 hour. When people cross an area, they correct their clocks by 1 hour (minus 1 hour to the west and add 1 hour to the east), and add or subtract a few hours when they cross several areas. This makes it easy to use.

Today, the world is divided into 24 time zones. Since it is often practical for a country or province to straddle two or more time zones at the same time, a country or province is often grouped together for administrative convenience. Therefore, the time zone is not strictly divided according to the straight line of north and south, but according to natural conditions.

For example, China has a vast territory and spans almost five time zones, but in fact, only the standard time of the East 8th time zone is used, that is, Beijing time. <>

Based on your question, I'm guessing you're asking about how time is divided. Here are some common ways to divide time:

1.Seconds, minutes, hours, days, weeks, months, years: this is the division of time according to the length of time, and it is the most commonly used way to divide time in people's daily life.

3.24-hour format: This method divides the day into two 12-hour periods, bounded by 12 hours, with different names for the time of day.

4.Twelve-hour clock: This method also divides the day into two 6-hour periods, but with 6 hours as the boundary, and the name of the time in the day is different from the 24-hour clock.

5.Hours, periods, hours, days, weeks, months, and years: This is a time division according to the length and continuity of time, and is often used for transportation, planning and management.

These are some of the common ways to divide time, and there are other more detailed and complex ways to divide time, such as solar time, solar time, true solar time, false solar time, and so on.