Encyclopedia of popular science knowledge: "Time Knowledge"

Chapter 8 Time's Fun Story (1)
funny jet lag

In 1978, China and the United States decided to establish formal diplomatic relations, and the governments of the two countries announced the establishment of diplomatic relations between China and the United States at the same time in Beijing and Washington.Chinese and foreign reporters hurriedly sent a telegram from Beijing to the world: "At 1978:12 am on December 16, 10, the Chinese government announced the formal establishment of diplomatic relations between China and the United States..." At the same time, Beijing received a telegram from the United States: "1978 At 12:15 p.m. on December 9, 16, the U.S. government announced the establishment of diplomatic relations between the United States and China..." According to the agreement, China and the United States announced the establishment of diplomatic relations in Beijing and Washington at the same time, but one was on the 15th and the other was on the [-]th.

After the China-U.S. route resumed, Northwest Airlines’ Boeing 747 took off from Shanghai Hongqiao Airport, arrived at Narita Airport in Tokyo, Japan for about 2 hours, rested at the airport for about an hour, and transferred to another 747 to cross the Pacific Ocean. The journey took a total of 16 hours.

Interestingly, the date when the plane took off from Hongqiao International Airport (such as 11:23 am on November 8) was actually the same day and the same time as the date when the plane arrived in Los Angeles.Think how wonderful the world is.

How is this going?It turns out that the earth keeps rotating from west to east while revolving around the sun along an elliptical orbit.

When the earth rotates, there is always half of the sphere facing the sun, and the sunlight illuminates it very brightly. That is the day, called the "day hemisphere"; Darkness, that is the night, called "Night Hemisphere".There is a dividing line between the day and night hemispheres, which is a large circle that divides the day and night hemispheres equally, called the "dawn and twilight circle".

With the continuous rotation of the earth, the direct point of the sun on the ground is constantly moving from east to west, and the twilight zone is also constantly moving from east to west. The day and night hemispheres are always alternating with each other, and the daytime becomes Night turned into night, and night turned into day again.

The rotation of the earth has important geographical significance.The rotation of the Earth produces the alternation of day and night.The earth rotates around its axis, and there are two relatively fixed points on the surface of the earth—the North Pole and the South Pole, which lead to longitude and longitude.At the same moment, places with different longitudes on the earth have different times.

People usually keep time according to the time interval between two sun climaxes.The earth is constantly turning, and different places on the earth have different times.When it is midnight in London, it is 0:7 in the morning in Beijing; when the sun is shining above Shanghai, it is a long night in Washington.

The time difference between different places, that is, their geographical longitude difference.It takes about 24 hours for the earth to rotate once, and the longitude of the earth is divided into 360°, that is to say, every 15°longitude, the time difference is 1 hour.

Beijing is located in the East 8th district, and Washington is located in the West 5th district. There is a difference of 13 time zones, that is, Beijing is 13 hours earlier than Washington. Therefore, when Washington is at 15:9 p.m. on the 16th, Beijing time is already at 10:[-] a.m. on the [-]th. .

同样道理，上海位于东8区，洛杉矶位于西8区，中间相隔16个时区，上海11月23日上午8时45分，洛杉矶正是11月22日下午4时45分。沿途经历了16小时，抵达洛杉矶的时间正是11月23日上午8时45分。

upside down season
On June 1978, 6, the World Football Championship was being held in the Argentine capital.Sputnik broadcast the game live to the whole world.There was a sea of ​​people on the field, and everyone was watching the game in fur coats and hats, while the Chinese spectators, wearing undershirts and shirts, sat around watching the TV and kept waving fans.In the end, the Argentine team defeated the Dutch team 25:3 and won the championship.

A major holiday in European and American countries - Christmas.It is snowing winter in the countries of the northern hemisphere. In the shop windows, old people with white eyebrows and white beards, wearing red leather jackets and pointed leather hats, carry big bags on their backs in snowy days, which is in harmony with the seasons.However, in countries such as Australia and New Zealand in the southern hemisphere, Christmas trees and Santa Claus are decorated with snow scenes in stores.But on the sidewalk outside the window, there are people with bare chests and backs, wearing gauze and silk, walking back and forth, which are completely opposite seasons.

Why are the seasons reversed on Earth?We have to start with the revolution of the earth.The earth revolves around the sun in an elliptical orbit.A full circle is a year.During the revolution, the earth's axis and the revolution orbit form an inclination of 66°34'.Moreover, the tilt direction of the earth's axis remains unchanged, and the North Pole always points near the Polaris.In this way, the direct point of the sun always moves back and forth between the Tropic of Cancer and the Tropic of Cancer.

Almost all the heat on the surface of the earth comes from the sun.The sun is far away from the earth, and the rays of light hitting the ground are almost parallel, but the earth is a sphere, and the angles of the sun are different at different latitudes.Some places are direct shots, some places are oblique shots.

The distribution of seasons in various regions of the earth is determined by this.The temperature here is highest when the sun is in direct or near direct sunlight, which is summer.When the sun is very low and slanting, the temperature is the lowest and it is winter.The sun in spring and autumn is also slanting, but the degree of slanting is not so great.

In the area near the equator, the sun is almost always directly shining, and the ground receives a lot of heat. Except for the high mountain area, the temperature is high throughout the year, so it can be said that "the four seasons are like summer".In the Arctic and Antarctic regions, the sun is obliquely shining, and sometimes the sun is not seen for several months, and the heat received is the least, and the climate is cold.

The temperate zone is different. With the north-south movement of the point of direct sunlight, the heat received by the ground is constantly changing, and the four seasons of spring, summer, autumn and winter appear.When the sun shines directly on the area near the Tropic of Cancer, the temperate zone in the northern hemisphere has strong sunlight, high temperature, and long days. It is a hot summer, but at this time, the southern hemisphere is just the opposite, and it is in a cold winter.

When the sun shines directly on the area near the Tropic of Capricornus, the temperate zone in the southern hemisphere is hot summer, while the temperate zone in the northern hemisphere has a cold climate and the shortest day.

When the sun shines directly on the area near the equator, the northern and southern hemispheres get equal heat from the sun, and the day and night are equally divided, which is a pleasant season.However, the spring and autumn seasons in the northern and southern hemispheres are just the opposite.

Australia, New Zealand, and Argentina are located in the southern hemisphere, while China, some countries in Europe and the Americas are located in the northern hemisphere.The earth is constantly moving, year after year, the seasons on the earth are constantly changing, and the seasons of the southern and northern hemispheres have always been reversed in this way.

Seven days in the middle of the cave, thousands of years have passed in the world

"Seven days in the mountains, thousands of years in the world." In ancient Chinese myths and novels, the speed of time between the fairy world and the human world is often described differently.The book "Yiyuan" by Liu Jingshu in the Southern Song Dynasty said that in ancient times, a man rode into the mountain and saw two old men with white hair and curly beard sitting cross-legged on the edge of a stone in the distance, playing chess facing each other.He came closer to watch, tied the horse to the stone, and held the whip in his hand.He was fascinated, knowing that after a while, he suddenly found that the whip in his hand had rotted and broken, the horse he was riding had turned into a pile of bones, and the saddle on the bones was also damaged.Knowing that something was wrong, he hurried back home, and there was no one living there. It turned out that Murakami had passed through countless generations.

There is a science fiction novel that boldly imagines future space travel: a rocket ship is heading towards Vega at a speed close to the speed of light, and soon disappears into the vast universe...it will not come back until more than 50 years later to the earth. ... When the passenger on this rocket ship returned to the earth from Vega, he felt as if it had only been a year or two, and he was still a handsome young man, but his friends in youth had become old men with long bells.

People can't imagine science fiction like this kind of mythology, and no one has taken it seriously.Newton believes that time is absolute, "whether things are moving or still, and whether we are asleep or awake, time always walks its own way." In his landmark book "Mathematical Principles of Natural Philosophy" , gave a famous definition of time: "Absolute and real mathematical time, as far as it is itself and its essence, flows uniformly forever and does not depend on any external things." Popularly speaking, what Newton thought Absolute time is like a straight line formed by points on a geometric straight line. It has no beginning and no end, and it always goes on forever and evenly in its own way.

Because of Newton's great popularity and the fact that this view fits with people's common sense, it has been believed for hundreds of years that there is indeed a "unique, universally applicable system of time that does not depend on anything else."But with the development of science, this point of view has presented many insurmountable difficulties.

At the beginning of the 1905th century, after long-term in-depth research and logical reasoning, the great scientist Einstein proposed the special theory of relativity in [-], and established a new concept of time and space based on the principle of relativity and the principle of the constant speed of light.

In 1916, he proposed the general theory of relativity, which caused a major change in the theoretical basis of physics.Einstein linked time and space because time is a relative.

Newton also said that the mass of an object is constant and does not change with speed.In the low-speed range, the difference between the dynamic mass and the static mass of the object is very small, and Newton's mechanics can also be applied.The so-called "low speed" here is relative to the speed of light. In macroscopic phenomena (such as the launch of rockets, the operation of artificial satellites, the movement of the solar system or the Milky Way, etc.), their speed is much smaller than the speed of light, and Newton's mechanics can still be applied.But in the microcosmic field, since the static mass of electrons, protons and other elementary particles is very small, their speed can easily reach a value close to the speed of light. At this time, Newtonian mechanics is no longer applicable, and relativistic mechanics must be used.

When scientists study the theory of relativity, they have learned that starting from the principle of "constant speed of light", they have drawn the conclusion that time is indeed relative.Space (or length) decreases as the relative velocity of the object increases.If a person looks at an object on the earth on a spaceship with a high speed, the length along the direction of motion will be shorter than when looking at it on the earth.The time will become larger as the relative velocity of the object increases.The mass of an object will increase with the increase of relative motion speed.The faster an object is moving, the greater its mass.

The theory of relativity reveals the mechanical laws of high-speed moving objects, and fundamentally changes the concepts of absolute space and absolute time that have been formed for a long time.Therefore, traveling freely in time will no longer be a dream.

The theory of relativity tells us that time is different in different inertial systems.The time on a high-speed rocket is slower than that on the earth.Although the current spacecraft has reached a speed of tens of kilometers per second, it is much smaller than the speed of light at 30 kilometers per second, so it has not yet become a reality.

However, the conclusion of special relativity has been confirmed by many results.When the particle moves close to the speed of light, the life-extending effect is very obvious.In high-energy accelerators or cosmic rays, it is easy to make particles move close to the speed of light.For example, there is a kind of elementary particle called muon.

Its lifespan is only 2 microseconds (two millionths of a second), so even if it moves at the speed of light, according to Newton's theory, it can only run 0.6 kilometers at most, but people have recorded muons 10 kilometers away. The life span is more than 10 times longer than that at rest.This is exactly the "relativistic effect" caused by the huge speed.

The conclusion that the lifespan of a moving particle is longer than that of a static one is also applicable to the lifespan of a human being.That is to say, the life span of a person in a state of high-speed motion is longer than that of a person at rest.If it were possible to build a vehicle that travels very close to the speed of light, the stuff of science fiction would become reality.

Number Nine and Plum Rain

"March [-] severe cold" is a phrase that people often talk about, but many people don't understand what "March [-]" is.

"Number Nine" is another invention of the Chinese calendar, and it is also one of the evidences that the lunar calendar has solar calendar elements.Our country has always counted from the winter solstice. The first nine days are called "Nine Nine", and the second nine days are called "Two Nine"... all the way to "Nine Nine".Generally, the lowest temperature in the whole year is between Sanjiu and Sijiu.There is a folk song in the Yangtze River Basin that gives a very vivid description: "No action in [-], walking on the river in [-], freezing of the river in [-], watching willows in [-], adding [-] to [-], plowing Cows are walking everywhere."

The weather in northern my country is colder than the Yangtze River Basin, so the content of the "Winter Nine Nine" ballad is slightly different: "The winter solstice belongs to the first nine, and the two hands hide the cuffs; Honey; four nine 27, go out on the ice; five nine 36, and the spring cold 45; six nine plus seven nine, don’t throw away the cotton clothes; eight nine and nine nine, start plowing the field.”

These folk songs are easy to understand and vivid, and can be linked with daily life and farming activities with little explanation.

Winter and summer are a pair of contradictions.There are three nines in winter and three volts in summer.There is an old saying: "Practice three days in winter and three days in summer." The so-called "three days", especially in the middle of the year, are often the hottest days of the year.The calculation of the three volts is more complicated: Chufu is from the third "Geng day" after the summer solstice to 10 days before the fourth "Geng day"; Zhongfu is from the fourth "Geng day" to the first day after the beginning of autumn. "Ji day"; Mofu is 10 days from the first "Geng day" after the beginning of autumn.Therefore, both the first and last periods are 10 days, while the middle period may be 10 days (such as in 2004) or 20 days (such as in 1998).

27 There is also "ninety-nine" in summer, but now it is little known. "Xia Jiujiu" is also divided into north and south, and they are all counted from the summer solstice.The ballads in the northern rural areas are: "36th to 45th, keep the fan in hand; 54th 63, the ice water is as sweet as honey, 72th 81th 27, the clothes are soaked with sweat; 36th 45, the breeze dances on the treetops; 54th 63, Don’t be too late to enjoy the cool; Seventy-nine 72, don’t sleep at night; Eighty-nine 81, be careful not to catch the cold; Ninety-nine [-], every family looks for cotton clothes.” Leaving hands; three nine [-], ice water is like sweet; four nine [-], sweating like a bath; five nine [-], tree head autumn leaves dance; six nine [-], do not enter the temple while enjoying the cool; seven nine [-], go to bed and look for sheets; eight Nine [-], think about finding quilts; Nine Nine [-], every family makes charcoal foundation."

In the Chinese lunar calendar, there is also a unique calculation method of "Meiyu" (also known as "mildew rain" and "yellow moldy sky").During this period of time, there were many cloudy and rainy days, the rain was falling, and the humidity in the air was very high. Many things were prone to mildew.

The day when the rainy season starts is called "Rumei", which is the first "Cing day" after Grain Grain; when it ends, it is called "Chumei", which is the first "Wei day" after Xiaoshu.Therefore, the plum rain season is roughly between June and July in the Gregorian calendar every year, which is when the plums are yellow and ripe.

flower life schedule

In nature, plants also have their own life timetable. Morning glory blooms in the early morning, blooms in full bloom against the sun at noon, and evening primrose blooms in the evening.Interestingly, almost all of these natural biological phenomena occur within a fixed period of time every day.

In the 18th century, the Swedish botanist Linnaeus observed these phenomena in nature. He once planted various flowers and plants with different flowering times in the garden in an orderly manner. Just look at what flowers were blooming in the flower beds at that time, and you will know that at that time About what time is it.This is really an interesting and peculiar clock - "Flower Clock".It is still maintained in gardens and crossroads abroad.

Different regions have different "flower clocks". In the same season, flowers and plants that bloom at different times can be combined into different "flower clocks".

In our country, the hops bloom first in the early morning (about 3 o'clock), and the trumpets of the morning glory also open at about 4 o'clock; ); Then there are beautiful and elegant tulips (about 5 o'clock) and banzhilian (about 6 o'clock), big claw grass (about 7 o'clock) in full bloom, noon flowers (about 10 o'clock) in full bloom against the scorching sun, noon Later, marigolds bloom (about 11 o'clock), mirabilis (about 12 o'clock) adds fragrance, and tobacco flowers (about 15 o'clock) bloom.As night falls, the moonlight flower (about 17 o'clock) spits out its pistils, and the night grass (about 18 o'clock) breaks buds to welcome the arrival of dawn.

On the bank of Qinghai Lake in my country, in the Manas Grassland of Xinjiang, in spring and summer, there is a small round flower of light yellow, which always blooms at 7-8 am; only open.At night, there is a small white flower that blooms from 6 to 8 o'clock and emits a fragrance similar to jasmine.Local herdsmen call these flowers "time-reporting flowers".

In countries such as the United Kingdom and the United States, a "flower clock" composed of 13 kinds of flowers is common. The spotted cat's ear blooms at 6 o'clock, the African marigold blooms at 7 o'clock, the mouse ear aster blooms at 8 o'clock, and the thorny bitter cauliflower blooms at 9 o'clock. Open, milky head grass opens at 10 o'clock, Star of Bethlehem opens at 11 o'clock, Passion flower opens at 12 o'clock, Dianthus closes at 13 o'clock, Crimson Chickweed closes at 14 o'clock, Little Iris closes at 15 o'clock, The small bindweed closes at 16:17, the white lotus closes at 18:[-], and the night grass opens at [-]:[-].

Another kind of "flower clock" is artificially decorated to beautify the city.The flower clock originated in the 17th century, but at that time it was only used as a decoration and did not really move. After the 19th century, mechanical flower clocks appeared.

There is a huge flower clock beside Lake Leman in Geneva: the mechanical structure is installed underground, and the clock face on the ground is a colorful pattern composed of flowers.The hour hand and minute hand on the clock face can indicate the time like ordinary clocks.The flowers on the clock face change with the seasons, so all the flowers are in full bloom all year round, colorful and charming.

my country Taiwan also has this kind of flower clock.The Flower Clock in Falls, USA is world famous.The clock face is composed of 2.4 flowers, with a diameter of more than 10 meters, the second hand is more than 5 meters long, and the hour and minute hands weigh more than 200 kilograms.

Recently, a flower clock with a unique shape and colorful colors was newly completed in Gomachi Town Park, Miyazaki Prefecture, Japan.This beautiful big flower clock has a diameter of 28 meters, a long needle length of 9.7 meters, and a short needle length of 6.9 meters. It is surrounded by flower beds composed of 2 sage plants and shuttlecock flowers.This big flower clock costs more than 10 US dollars and is currently the largest flower clock in the world.

"Honeymoon Trip" of Shrimp and Crab

(End of this chapter)