The concept of time, what is the concept of time?

In the theory of relativity, time and space together form a four-dimensional space-time, which constitutes the basic structure of the universe, so time cannot be measured by a spatial scale alone. From the point of view of classical mechanics, the irreversibility of time is inexplicable. The irreversibility of time can only be explained theoretically from the point of view of statistical mechanics and thermodynamics.

The second law of thermodynamics says that in a closed system (we can think of the universe as the largest possible closed system) entropy can only increase, not decrease. Entropy in the universe cannot decrease when it increases, so time is irreversible.

Actually... Everything is a floating cloud, and this lump floats by, and it never comes back...

You can use this sentence as a poem, or you can understand it as "philosophy", if you consider it from an academic point of view, it is a bit naïve, in fact, even the road can only move forward and not retreat, our so-called backwards are only ideological, can you really retreat to the road you walked a minute ago? Unless you can travel through time.

The nature of time: Time is a measure of the sequence of events, a dependent variable, and it changes with the universe.

The process of change in the state of all macroscopic matter is continuous and irreversible, and this property is their common property, and the measure of this continuous event is called time.

In that case, can time be measured with a ruler?

Since time is length, why can't it be measured by a ruler?

For example, in meters, I can walk between one meter and two meters.

If it's a length, why can you only move forward and not go backward?

Look at Einstein's theory of relativity, and you'll know that time is relative.

A blind explanation of time.

1) [time]

2) the specific minute, hour, day or year on the clock or calendar; Exact time or date Time is midnight What time is it (3) The period during which a thing (e.g., certain action, process, or circumstance) exists or continues (4) [present,now] At present, although the present time is embarrassed, it will inevitably occur after a long time. - Yuan · Qin Jianfu "Hair Cutting and Waiting" (5) [a moment] A very short time for a time Temperament on the evacuation Detailed explanation (1).Right now, for a while.

Jin Dong Xie Yuan, "The Legend of the West Chamber" Volume 1: "Time is still in white, and the current situation is unsuccessful. Ling Jingyun Proofreading:

Time, refers to the present, the present. Yuan Qin Jianfu "Hair Cutting and Waiting for Guests" The first fold: "Although the time is embarrassed, it will inevitably develop after a long time."

The seventh chapter of "Water Margin": "It turned out to be the official Gao Taiwei's Yanei, who didn't recognize Jing Nu, and time was rude." ” 2).

Immediately, immediately. The fourth chapter of Journey to the West: "If he doesn't follow, time will hit the Lingxiao Treasure Hall and teach him that the dragon bed will not be able to sit down."

1).For space, it is a continuous system composed of past, present, and future. Qu Qiubai "Chronicle of the Hungry Country" II:

Qingyun "does not know what value his transformation will give birth to in space and time." Ai Qing's poem "To the Sun": "You are the forger of time, the goldsmith of a beautiful life."

2).There is a period of time when there is a beginning and an end. Cao Yu "Pekingese" Act I:

He grew up in a scholarly family in Beiping, playing chess, writing poems, and painting, which naturally took up a lot of time in his life. Qin Mu's "Yulin Caiying's Postscript": If you make time to write such a small book, you can urge yourself to study.

3).Refers to a certain point in time. Bing Xin, "Our Wife's Living Room":

The time is an ideal spring afternoon in Beiping, warm and bright. Ding Ling, "Shanghai in the Spring of 193" II: "There is no certainty, and there is no certainty in time and place.

Word decomposition Explanation of time Hour (time) The process that everything goes through in the process of constantly evolving and changing: time. Lost time is never found again.

hours. Now, current: then.

Nowadays. Current Affairs. The right time .

Often: often. Learn and learn to grind positive numbers.

Interpretation of the year The place where two periods of time meet, or between two things and their interrelationships: the middle. Spacing.

Interlude. between heaven and earth . In a certain space or time:

Field. Room. The partitioned parts of the house:

Inside. Cloakroom. Volume.

Measure word, the smallest unit of a house: one room.

Time [2] is a relatively abstract concept, which is the expression of the movement of matter, the continuity of change, and the sequentiality. The concept of time consists of two concepts: time and period.

Timed explanations.

1) [time] Ignition or timed explosion at the specified time 6* Explosion timed explosion 6* medicine (2) [definite-time] has a purposeful delay action, regardless of the intensity of the operating force, the delay time is roughly the same Huichun, especially for relays (3) [determinated time] determine the time (4) [accoding to the fixed time] on time, according to the determined time Detailed explanation (1).Punctual and in accordance with the stipulated time. "Water Margin" Chapter 57:

Liang Shanbo asked Ling Zhen to create all kinds of big disasters, and when he was timed, he went down the mountain to face the enemy. Ding Ling, "My Mother's Life": During the few years that my mother lived in Beijing, she would get up early to write and copy books in the morning, read books (including literature and science books), and do some handicrafts in the afternoon, knitting sweaters for us, sewing and mending.

Gu Jiegang, "Ancient History: Self-Introduction": If I had been able to do things at the right time, my mind would have been much more stable; It's just like others don't have the concept of working on a regular basis. ”2).

A certain amount of time. Qu Qiubai, "History of the Heart of the Red Capital" 32: "There is a quantitative timing for diet.

The word decomposition definite interpretation 定 ì immovable, unchanging: quota. Pricing.

Law. Conclusion. Regular.

Stereotypes. Definition. Dingdu (?

Finalized. Definite number (?.)a Prescribed amount; b Refers to the Mandate of Heaven; c Prescribed amount).

Vouch. Stipulate. Identification.

No change: final. Conviction.

Decision. Are you sure. Peace, peace (mostly refers to the situation):

The die is cast. Calm, calm (mostly emotional): unsettled.

Certain, certainly: definitely. Stabilization.

Advance Appointment: Determined. Affection.

Ordering. Customize. Surname.

Radical: 宀; Explanation of time The process through which everything is constantly evolving and changing: time.

Seasonal. hours. Present, current:

Then. Nowadays. Current Affairs.

The right time . Often: often.

Learn and learn. Season of the year: Timings.

Four o'clock is like spring. In the old days, one-twelfth of a day and night was an "hour", eleven o'clock in the evening to one o'clock in the morning was the "sub-hour", and eleven o'clock to one o'clock in the afternoon was "noon". The current unit of time, one-twenty-fourth of a day and night:

Clock. Jet lag (?.)So-and-so.