Astronomical knowledge popular science constellation

Astronomical knowledge popular science constellation

Astronomical knowledge popular science constellation, constellation is very useful in our daily life. The zodiac is closely related to the movement of the sun. This constellation is generally mysterious and romantic, and fortune is not equal to fortune telling. Let's share the knowledge of astronomy and popular science constellations. I hope I can help you.

Astronomical knowledge popular science constellation 1 is an indispensable part of astrology and a group of stars in the sky. Since ancient times, human beings have associated three or five stars with their mythical figures or artifacts, which are called "constellations". Constellation is a means to determine the orientation of the sky in almost all civilizations and is widely used in the field of navigation. The division of constellations is completely artificial, and different civilizations have different divisions and names. Constellations have no uniform and precise boundaries. Until 1930, in order to unify the complicated constellation division, the International Astronomical Union divided the sky into 88 official constellations with precise boundaries, so that every star in the sky belonged to a specific constellation. Most of these official constellations are based on ancient Greek myths handed down from the Middle Ages. In contrast, some widely circulated star combinations are not recognized as official constellations, such as the Big Dipper (see star list).

In the three-dimensional universe, there is no necessary connection between these stars. Their positions on the celestial sphere are similar, but in fact they may be far apart. If we were in another solar system of the Milky Way, the starry sky we saw would be completely different. Since ancient times, people have been interested in the arrangement and shape of stars, and naturally linked some stars with similar positions to form constellations.

The origin of constellations

Mesopotamian astrologers divided the starry sky into several regions for the convenience of studying and observing many stars in the sky, and each region was a constellation. It's hard to say clearly when humans began to have the concept of constellation. This astronomical knowledge was known long before there was a historical record. The name of the constellation probably comes from the sailors who sailed early.

The origin of constellations may be completely different between civilizations in different regions, but with the expansion and mutual influence of civilizations, the culture of constellations also includes the process of integration.

the west

In 270 BC, the Greek poet Aratus wrote Things, in which 47 constellations were mentioned. According to the star regions recorded in Celestial Bodies, due to precession, the Antarctic in the period described in the book is not consistent with the current Antarctic, so it can be inferred that the starry sky recorded in the book is before 2000 BC; At the same time, the blank area of the starry sky record indicates that the observer should be near 35 to 36 north latitude. So some people think that the practice of dividing the starry sky into constellations originated from Babylon and Sumer in Mesopotamia, and the constellations of Greece and Egypt may have been introduced from this area.

In the Book of Job, several constellations such as Bear and Orion are mentioned. In the12nd century BC, the land landmarks built in the era of Nebuchadnezzar I were engraved with designs of Sagittarius, Scorpio and Ophiuchus. The ancient Greek poets Homer and hesiod also mentioned Ursa major, Orion and the Pleiades (the Pleiades was considered as an independent constellation at that time, not a part of Taurus), and at the same time, Babylon had recorded the zodiac in cuneiform.

In the second century, Ptolemy recorded 1022 stars in 48 constellations in his astronomical masterpiece, which is also the embryonic form of modern constellations. After that, many astronomers filled the Ptolemaic constellation with new constellations. Valle in 1603, Jahannes Hewelius in 1690, and Llakaj in 1752 have named the constellations in Nantian in two centuries.

China

See: star officer, three walls, four elephants, twenty-eight nights.

There are some names of 28 homestays in the early Zhou Dynasty in Zhou Li, which was written in the Spring and Autumn Period and the Warring States Period. Records of twenty-eight huts and four elephants were first found in historical records. There are many differences in academic circles about the origin, time and place of Twenty-eight Nights. Traditionally, China's twenty-eight lodging system can only be traced back to the eighth and sixth centuries BC. 1978, archaeologists unearthed the lacquer box cover engraved with the image of Twenty-eight Hostels in the tomb of Zeng Houyi of the Warring States Period in Suizhou, Hubei Province, which is the earliest physical specimen of Twenty-eight Hostels discovered so far.

In ancient China, Sanyuan, which is near the North Pole, was defined as a middle official, while Erbasu was actually subdivided from four elephants. The star area south of Erbasu was called a foreign official, that is, "middle official+four elephants+foreign officials", which was just one of the many ways to divide the star areas in ancient China. In addition, there are many ways to divide the stars into seven areas, such as "five beasts+middle officials+foreign officials" and "nine wild+middle officials+foreign officials" into 1 1 area, but the division method of "middle officials+four elephants" is widely spread.

In ancient China, the sky was divided by star officials. The earliest record of star officials is Sima Qian's Book of Historical Records, which contains 9 1 star officials and more than 500 stars. By the Sui Dynasty, there were 283 star officials recorded in Song of Heaven, belonging to one of the three yuan or twenty-eight lodging houses. Sanyuan refers to the three regions surrounding the Arctic sky, namely Ziweiyuan, Taiweiyuan and Tianshiyuan, which are divided into four elephants around the ecliptic and the celestial equator, and each elephant is subdivided into seven regions of the four elephants, collectively called Twenty-eight Hostels. In ancient China, the lunar calendar was used as a calendar year. Because the moon rotates once around the earth on the 28th of every month, it is called a "shelter" or "shed" when it passes through an area every day. At the end of the Ming Dynasty, due to the influence of western learning spreading to the east, Xu Guangqi compiled the almanac of Chongzhen with reference to the data of European astronomy, adding 23 star officials near Invivo.

There are different opinions about the order in which the starry sky is divided into three walls, four images and twenty-eight nights. Gaul, an astronomer in the Republic of China, thought in his book Notes on Astrology that three walls appeared first, then four elephants, and finally appeared for 28 nights. Chen Zungui, an astronomer who was the first curator of the Beijing Planetarium, thinks in his works that these four images appeared earlier, and then they were divided into twenty-eight lodges, with Sanyuan being the last one, and points out that the name of Sanyuan only appeared in the Song of Dan Deng Tian in the Sui Dynasty, and the shape of Sanyuan and Twenty-eight lodges was also formed and used here.

India

See: Twenty Seven Nights

Indian's Nakshatra (meaning "Moon Station") is very similar to China's Twenty-eight Nights, and scholars believe that they all come from the same source. Pipaxing, Madler, schlegel, Zhu Kezhen, Xia Nai, Xincheng Xinzang and others claimed that 28 hotels originated in China. Weber, John Chen, Ginzel, kingsmill and Edkin advocated the origin of India.

Different from the division of China's Twenty-eight Lodgings, Indian Twenty-eight Lodgings replaced Niu Lodging in China's Twenty-eight Lodgings with Weaver Maid, and replaced female Lodging in China's Twenty-eight Lodgings with River Drum (Cowherd). Both of them started with Kakuk (,Chitrā), but the starting place of 28 hotels in India was changed to Pleiades (,Krittikā). According to ancient Indian classics, rooms and walls were once combined into one night and became twenty-seven nights, or there were twenty-seven nights made by subtracting the Weaver Girl, which is consistent with China. The full name of the Twenty-Seven Hostel first appeared in Brahma's Partridge Book.

Arab world

After the 9th century, Ptolemy constellation spread to the Arab world. Ptolemy's masterpiece Astronomy was translated into Arabic, which was called "the great theory". On the basis of this book, Al Su Fei wrote The Stars, which is one of the three masterpieces of Islamic observational astronomy. Most of the star names used around the world now come from Arabic.

Significance and application of constellation

It is almost as difficult for friends to meet each other as the stars in the morning and evening.

Du Fu's Eight Guards for Chu Shi. As mentioned in the ancient poem, the two stars of Shen and Shang, one east and one west, will never meet. Betelgeuse is actually Orion; Xinsu, also called Shangsu, is a Scorpio; "It's almost as difficult for friends to meet, and as for the stars in the morning and evening" refers to these two places, Scorpio and Orion.

In ancient times, the rise and fall of stars or constellations were often used to navigate and determine time. Ancient Egypt determined the beginning of a year by observing the rise of Sirius. In some areas, the ancient technology of determining position by observing stars still remains. Constellations and the literary images they represent often appear in the works of literati.

Although the importance of constellations has been relatively reduced in modern times, they have not lost their charm for astronomy lovers. Through its fascinating legend, constellations have played an extremely important role in the popularization of astronomy. Whenever there is a major astronomical phenomenon, astronomers, popular science workers and the media will always set off an astronomical upsurge in society, especially among young people.

What is the main sequence star of Astronomical Knowledge Science Constellation 2?

On the Herro diagram, the distribution of stars is not random, but concentrated in several areas. The most conspicuous thing is a narrow band from the upper left corner to the lower right corner along the diagonal. Most stars, including the sun, are on this diagonal line from the upper left corner to the lower right corner. This diagonal line is called the main sequence, and the stars on the main sequence are called the main sequence stars. They are all in the hydrogen combustion stage of their lives. When hydrogen burns, helium will start to burn and expand into a red giant. The sun in the solar system is the main sequence star.

Basic definition

A main sequence star is a star located in the main sequence. When the central temperature of the protostar reaches about 6.5438+million K, the thermonuclear reaction of hydrogen fusion into helium nucleus continues to occur. Due to the huge radiant energy generated by nuclear reaction, the internal pressure of the star is increased enough to compete with gravity, and the star enters a relatively stable period and reaches a complete hydrostatic equilibrium state. The stars in this period are called main sequence stars. The difference and dividing line between protostar and main sequence star is whether there is a continuous thermonuclear reaction inside the star.

When the hydrogen in the star nucleus is burned out, they leave the main sequence star stage and start burning helium, becoming red giants. Eventually, the red giant collapsed and the temperature rose, becoming a white dwarf. Those whose luminosity is less than that of superstars and Supergiant star of the same spectral type are also called dwarfs. In MK binary star spectral classification system (see stellar spectral classification), the Roman numeral V is used to indicate its luminosity level. 90% of the observed stars are main sequence stars. The energy of the main sequence star is mainly the thermonuclear reaction of hydrogen fusion into helium in the nucleus. In the process of star evolution, it stays at this stage for the longest time. Stars of different masses stay in the main sequence stage for very different times. The greater the mass of the star, the faster the hydrogen consumption and the shorter the stay time in the main sequence star. One star with solar mass is 65.438+00 billion years, 30 stars with solar mass are 65.438+00 billion years, and 0.5 stars with solar mass are 65.438+00 billion years.

Main sequence stage

The development stage of a star with internal hydrogen fusion as its main energy source is the main sequence stage of the star. Stars in the main sequence star stage are called main sequence stars. The main sequence stage is the youth and middle age of the star, and the time that the star stays in this stage accounts for more than 90% of the whole life. This is a relatively stable stage, the two forces of outward expansion and inward contraction are roughly balanced, and the stars basically do not contract or expand. The time that a star stays in the main sequence phase changes with the change of mass. The greater the mass, the greater the luminosity, the faster the energy consumption and the shorter the time to stay in the main sequence stage. For example, stars with mass equal to 15 times, 5 times, 1 times and 0.2 times the mass of the sun are in the main sequence stage 1 0 million years, 70 million years,10 billion years and11 trillion years respectively.