After teaching the basic theoretical knowledge, Shuguang Academy began to release various training tasks. And the students in this period were relatively free, Hua Feng and Yun Meng and Bai Feng formed a team.

Among all the students, it is also the rule of the academy to freely combine into a team, and as long as the strength is enough, no one cares whether you are three or two. As a result, the Dawning Academy was scattered and combined into thousands of squads, and the average combat power in each squad was around the 61-level Yuan Emperor.

And Hua Feng, who had loosened up the time, began to follow Sun Wukong more devotedly to learn some plausible things after explaining the affairs of the farm and the affairs of the family, and the knowledge of galaxies was becoming more and more refined......

Since the sun is located in the silver plate, it is not easy for us to recognize the original appearance of the silver plate. In order to understand the structure of the silver disk, according to the study of the spiral arm of the spiral galaxy M31 (Andromeda Galaxy) by Bard and Mayol in the 40s of the 20th century, the main types of spiral arm objects were obtained, and then these types of objects were surveyed in the Milky Way, and three parallel arms near the sun were found.

Because of the interstellar extinction, optical observation cannot determine the overall appearance of the silver disk. There is evidence that the spiral arm is a site of interstellar gas accumulation, so that the detection of interstellar gas can reveal the spiral arm structure, and the 21 cm radio spectral line of interstellar gas is not blocked by interstellar dust and can reach almost the entire Milky Way. Both optical and radio observations show that the silver disk does have a vortex structure.

The silver disk is mainly composed of star family I. objects, such as G~K type main-sequence stars, giants, novae, planetary nebulae, Lyra RR variables, long-period variables, semi-regular variables, etc.

The center of the Milky Way, the intersection of the Milky Way's axis of rotation and the galactic plane. In the central protrusion of the galaxy, it is very bright spherical, about 20,000 light-years in diameter and 10,000 light-years thick, and this region is made up of a dense density of stars, mainly red stars that are about 10 billion years old. Evidence suggests that there is a huge black hole in the central region and that galactic nuclei are very active.

The silver heart is in the direction of Sagittarius, and the coordinates of the 1950 epoch are: right ascension 17° 42′ 29", declination -28° 59′ 18".

In addition to being a geometric point, the silver heart also refers to the central region of the Milky Way. The Sun is about 10,000 parsecs away from the center of the galaxy and about 8 parsecs north of the galactic surface. There is a large amount of interstellar dust between the galactic center and the solar system, so it is difficult to see the galactic core in the visible light band with an optical telescope in the northern hemisphere.

With the advent of radio astronomy and infrared observations, it was only possible to detect the galactic core in the 2 μm to 73 cm wavelength band through interstellar dust. Observations of the 21 cm spectral line of neutral hydrogen revealed that there was a hydrogen flow expansion arm at a distance of 4,000 parsecs from the silver core, the so-called "3,000 parsec arm" (the distance was initially mistaken as 3,000 parsecs, but later revised to 4,000 parsecs, but the old name was still used).

There are about 10 million solar masses of neutral hydrogen rushing to the solar system at a speed of 53 km/s. On the other side of the core, there is a neutral hydrogen expansion arm of roughly the same mass, which is moving away from the center at a speed of 135 km/s. They should have been ejected from the galactic core in an asymmetrical manner 10 million ~ 15 million years ago.

In the celestial area 300 parsecs away from the galactic core, there is a hydrogen disc that rotates rapidly around the galactic core, expanding outward at a speed of 70~140 km/s. There is a cloud of hydrogen molecules with an average diameter of 30 parsecs in the disk.

At a distance of 70 parsecs from the galactic core, there is a region of ionized hydrogen with intense disturbance, which expands outward at high speed. It has been learned that not only is a large amount of gas gushing out of the galactic core, but there is also a strong radio source at the galactic core, Sagittarius A, which emits intense synchrotron acceleration radiation. Very long baseline interferometer probes show that the central region of the galactic radio source is small, even less than ten astronomical units, i.e. no larger than Jupiter's orbit around the Sun.

Infrared observations of 12.8 microns indicate that the mass of a silver nucleus with a diameter of 1 parsec is equivalent to the mass of millions of solar masses, of which about 1 million solar masses are in the form of stars.

The galactic core region has a massive dense nucleus, perhaps a black hole. Relativistic electrons flowing into the dense core accretion disk are accelerated in a strong magnetic field, producing synchrotron accelerating radiation.

Recent observations of the galactic core show that the core of the Milky Way is almost entirely composed of white dwarfs, with at least 100,000 of them. The core of the heart is made up of about 70 large white dwarfs. As for how to observe more, scientists say it will be done with next-generation observing equipment, such as NASA's James Webb astronomical telescope, which is under construction.

The galactic halo is scattered in a spherical region around the galactic disk, which is about 98,000 light-years in diameter, and the density of stars here is low, with globular clusters of older stars distributed. It has been suggested that there is also a large spherical region of radio radiation outside the galactic halo, called the silver crown, which extends at least 100 thousand parsecs or 320,000 light-years away from the galactic core.

The Milky Way is shrouded in a silver halo about 30 thousand parsecs in diameter. The brightest members of the galactic halo are globular clusters.

In astronomy, the crown refers to the gas envelope around the celestial body, the outermost layer of the celestial atmosphere is very similar to a hat on people's heads, wrapping the "round face" of the stars, the word crown originally referred to a kind of hat (top hat) on the head of the ancient emperor, and this hot gas in the sky also looks like a hat, so now people call this gas silver crown. The corona of the sun is known as the corona, and the corona of stars is called the corona.

The solar system is located on a spiral arm called the Orion Arm, about 26,400 light-years from the center of the Milky Way, and it takes about 250 million years to rotate counterclockwise around the galactic core.

The solar system is located near the inner edge of the Orion spiral arm, and in the Local Fluff, 7.94±0.42 kiloparsecs from the center of the Milky Way, our spiral arm is about 6,500 light-years away from the adjacent Perseus arm (measured by measuring the distance from the nucleus of a massive molecular cloud about 6370 light-years from Earth). Our solar system is located in the so-called galactic life belt.

The direction in which the Sun is moving, also known as the Solar Direction Point, points out the path of the Sun as it travels through the Milky Way, essentially towards Vega, near the constellation Hercules, about 86 degrees away from the center of the Milky Way. The Sun's orbit around the Milky Way is roughly elliptical, but is subject to some disturbance by the uneven distribution of the spiral arms and mass, and we are currently close to 1/8 of the orbit near the perigalactic center (the point at which the Sun is closest to the center of the Milky Way).

The solar system orbits around every 2.25~250 million years, which can be called a galactic year, so it is estimated that the sun has circled the Milky Way 20~25 times based on the age of the sun. The orbital speed of the Sun is 217 km/s, which means that it can move 1 astronomical unit every 8 days, and it can travel a distance of 1 light year in 1400 years.

Milky Way Waves:

Scientists used the photometric and spectral data from the Sloan Digital Sky Survey to study the Milky Way's silver disk. The results have upended the textbook image of the Milky Way, suggesting that the silver disk has a wavy structure and that the size of the silver disk may also be larger than traditionally believed [6].

The conventional wisdom is that the galactic disk of the Milky Way should be a smooth disk, with an exponential decrease in density from the center of the galaxy outward, and that the density should be mirror-symmetrical on the upper and lower sides of the disk (or north and south). In 2002, Heidi Newberg and her colleagues at Rensselaer Polytechnic Institute in the United States discovered that there is a dense mass of stars on the outermost edge of the silver disk, and this cluster structure is called the Monocerosis ring. Later, other astronomers discovered another similar substructure outside the Monocerosis rings, known as the Triangular-Andromeda Stream.

A team of researchers further analyzed observations from the 2002 Sloan Digital Sky Survey and found signs of two other similar substructures. These other two substructures are located between the Monocerosis rings and our Sun. The closest substructure to the Sun is about 30,000 light-years away from the galactic center, and the stellar density north of the galactic disk is higher than expected, and the other substructure is about 40,000~45,000 light-years away from the galactic center, and the stellar density south of the galactic disk is higher than expected.

They are named Near North Structures (

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Methods for estimating the age of galaxies:

Based on the known decay time (i.e., half-life) of long-lived radioactive nuclei, the abundance data of certain radioactive neutron capture elements can be used to determine the age of the oldest star in the Milky Way, and thus the age of the Milky Way, a radioactive dating method called nuclear dating.

For example, the half-life of thorium is around 13 billion years. With the largest astronomical telescopes of our time, coupled with high-resolution spectrometers, it has been possible to detect the thorium of stars and estimate their age accordingly.

According to various methods, the age of the universe is about 14 billion years since the Big Bang. Assuming that the time between the Big Bang and the formation of the Milky Way is 1 billion years, then the age of the Milky Way as determined by nuclear dating described above is compatible with the age of the universe.

According to a study by the European South Observatory of Heaven (ESO), it is estimated that the age of the Milky Way is about 13.6 billion years old, almost as old as the universe.

In 2004, a team of astronomers using the Very Large Telescope's (VLT) ultraviolet vision matrix spectrometer discovered beryllium for the first time in two stars of globular cluster NGC 6397.

This discovery allowed them to advance the time of the alternation of the first generation of stars and the second generation of stars by 2~300 million years, so it is estimated that the age of the globular cluster is about 12±95 billion years old, so the age of the Milky Way will not be less than 12±28 billion years old.