What does a galaxy mean?

Question 1: The difference and definition of galaxies: In the vast universe and ocean, there are various "islands" dotted with countless stars and various celestial bodies, which are called galaxies in astronomy. The earth where we live is in a huge galaxy-the Milky Way. In the universe outside the Milky Way, there are hundreds of millions of space giant islands similar to the Milky Way, collectively known as extragalactic galaxies. Cluster: Among the numerous stars in the Milky Way, there are many stars gathered together, not only in the form of single star, but also in the form of double stars or multiple stars. A cluster with more than 10 stars is called a cluster. What binds these stars together is gravity. There are thousands of members in the cluster. They can be divided into open clusters and globular clusters. There are clusters everywhere in the Milky Way, but the types of clusters are different in different places. Nebula: Nebula is a cloud-like celestial body composed of gas and dust in interstellar space. The density of matter in the nebula is very low. If measured by the standards on earth, some places are almost vacuum. However, the size of the nebula is very large, often reaching tens of light years in Fiona Fang. Therefore, nebulae are generally much heavier than the sun. Nebulae have various shapes. Some nebulae are irregular in shape, diffuse and have no clear boundaries, which are called diffuse nebulae; Some nebulae are called planetary nebulae because they are like a disk, emitting faint light, much like a big planet. Constellation: Compared with galaxies, constellations are more emotional. Constellations are divided according to the gathering patterns of stars that can be observed in the night sky, and the division is based on vision rather than real star positions. Therefore, the stars in the same constellation often come from different galaxies, and are artificially divided into constellations when they reach the earth from different positions in the universe with visible light.

Question 2: What do you mean by the Milky Way Star Reserve? It includes the Milky Way and extragalactic galaxies, and consists of billions to hundreds of billions of stars, interstellar gas and dust. Galaxies vary in size, ranging in diameter from several thousand light-years to hundreds of thousands of light-years, and their mass ranges from 65.438+billion to 65.438+billion times the mass of the sun.

The overall distribution of galaxies in space is close to uniform distribution, but on a small scale, the distribution of galaxies is uneven and tends to gather. There are various shapes of galaxies, which can be roughly divided into five types: elliptical galaxies, lens galaxies, spiral galaxies, rod spiral galaxies and irregular galaxies.

Question 3: What does the Milky Way mean in social security? Galaxy is an astronomical concept, and social security is a sociological concept. The two are completely unrelated fields, and there is no * * * relationship between them.

On the Origin and Evolution of the Earth defines a galaxy as: in the universe, the combination of orbital movements formed by two or more planets is called. The English word galaxy comes from the Greek word γ α λ α ξ? α? (Galatians). A galaxy in a broad sense refers to an operating system consisting of countless star systems (including the stars themselves, of course) and dust (such as nebulae). Speaking of our Milky Way, it is a huge system, including stars, clusters, nebulae, interstellar gas substances, cosmic dust and dark matter, bound by gravity, usually millions of light years away. Galaxies, with tens of billions of stars on average, are the basic units of the universe. Typical galaxies, from dwarf galaxies with tens of millions (107) stars to elliptical galaxies with trillions (10/2) stars, all revolve around the center of mass. Except for individual stars and thin interstellar matter, most galaxies have a large number of multi-star systems, clusters and various nebulae.

Galaxies are mainly divided into three categories: elliptical galaxies, spiral galaxies and irregular galaxies. A more explicit and extensive description of galaxy types will be described in the entries of Haber sequence. Because Haber's sequence is based on visual patterns, he may miss some important features of galaxies, such as star formation rate (at the core of starburst galaxies or active galaxies).

According to Haber's classification, the E type of galaxies represents elliptical galaxies, the S type represents spiral galaxies, and the SB type represents rod-shaped spiral galaxies.

On a clear night without light interference, if the sky is dark enough, you can see the diffuse light bands in the sky. This band of light is what we see when we look at the Milky Way from the inside. It is a round surface full of stars-a silver disk. There are about 200 billion stars in the Milky Way, but they are too far away to be recognized by the naked eye. Because starlight is mixed with interstellar dust gas, it looks like a band of light shrouded in smoke. The center of the Milky Way lies near Sagittarius.

The Milky Way is a medium-sized star system, and its silver disk is about120,000 light years in diameter. Its silver disk contains a lot of interstellar dust and gas clouds, which gather into a red star-forming area, thus constantly supplementing the spiral arms of galaxies with hot young blue stars, forming many open clusters or clusters of galaxies. There are more than 1200 such open clusters. Around the silver disk is a huge silver halo dotted with stars and globular clusters mainly composed of old stars.

Extragalactic galaxies are celestial systems similar to the Milky Way, and their distance is beyond the scope of the Milky Way, so they are called "extragalactic galaxies". Andromeda galaxy is an extragalactic galaxy located in Andromeda. Extragalactic galaxies, like the Milky Way, are also composed of a large number of stars, clusters, nebulae and interstellar matter. We can observe as many as 1000 billion extragalactic galaxies.

Social insurance refers to a non-profit social security system with the function of income redistribution. It is a system that forces most members of society to participate in order to prevent and share social risks such as old age, unemployment, illness and death and realize social security. Social insurance is a social and economic system that provides income or compensation for those who lose their ability to work, are temporarily unemployed or suffer losses due to health reasons. The social insurance plan is organized by * * *, forcing a certain group to use part of its income as social insurance tax (fee) to form a social insurance fund. Under certain conditions, the insured can get fixed income or loss compensation from the fund. It is a redistribution system, and its goal is to ensure the reproduction of material and labor and social stability. The main items of social insurance include old-age social insurance, medical social insurance, unemployment insurance, industrial injury insurance and maternity insurance.

Social insurance refers to a compulsory security system in the form of national legislation, with workers as the protection object and special events such as old age, illness, disability, unemployment and death as the protection content.

Social insurance and commercial insurance are two different forms of insurance. In the second chapter, we divide insurance into social insurance and commercial insurance based on profitability. Whether it is profitable or not is the most important sign to distinguish these two kinds of insurance, but if we make a detailed analysis, there are still many differences between them. The characteristics of social insurance can be seen from the comparison between social insurance and commercial insurance.

1. Not for profit.

2. Mandatory.

3. Universal security.

4. Rights and obligations >>

Question 4: What is a galaxy? A huge celestial body composed of countless stars and interstellar matter is called a galaxy. Their scales range from thousands of light-years to hundreds of thousands of light-years. Galaxy or star system is an important part of the universe system. There are many galaxies. So far, people have observed about 654.38+000 billion galaxies in the universe. The earth is in the Milky Way, which is composed of10 billion stars and the Milky Way Nebula. Some galaxies are close to the Milky Way, and their structures can be clearly observed. The nearest galaxies to the Milky Way-large magellanic cloud and small magellanic cloud-are more than100000 light years away. Some galaxies are very far away, and the farthest known galaxy is nearly 65.438+0.5 billion light years.

People call the currently known part of the universe, including all the observed galaxies, the total galaxy.

Question 5: What is a galaxy? The word galaxy comes from the Greek Galaxis (γ α λ α ξ? α? ) refers to our Milky Way, which is a massive system containing stars, interstellar gas, cosmic dust and dark matter and bound by gravity. Typical galaxies, from dwarf galaxies with tens of millions (107) stars to elliptical galaxies with trillions (10/2) stars, all revolve around the center of mass. Except for individual stars and thin interstellar matter, most galaxies have a large number of multi-star systems, clusters and various nebulae.

Historically, galaxies have been classified according to their types (usually their visual shapes). The most common is the elliptical galaxy, which has a bright appearance of elliptical shape; Spiral galaxies are disc-shaped, with curved arms of dust; Irregular or abnormal shapes are usually the result of the influence of other nearby galaxies. The interaction between adjacent galaxies may lead to the merger of galaxies, or lead to the production of a large number of stars, becoming so-called starburst galaxies. Small galaxies lacking an organized structure will be called irregular galaxies.

Question 6: What are the top ten galaxies? 1, Milky Way

2. Andromeda galaxy

3. Virgo galaxy group (including NGC4552 galaxy, NGC4486 galaxy, NGC4479 galaxy, etc. )

4. Abel 22 18 Galaxy Group

5. Large/Small Magellanic Galaxies

6.NGC205 elliptical galaxy belongs to E6 type and is located in Andromeda.

7. NGC3 1 15 located in sextant is an E7 elliptical galaxy, part of which is classified as S0.

8.NGC3623 is located in Leo and belongs to Sa spiral galaxy.

9. spiral galaxy 9.NGC3627, located in Leo.

10, NGC5 194 canine spiral galaxy, belonging to Sc type. On the left is a dwarf galaxy.

Question 7: What is a galaxy? Galaxy is an "island" of giant stars in the universe, and it is also one of the largest and most beautiful celestial systems in the universe. So far, people have observed about 1000 billion galaxies in the universe. Some are close to us, and their structures can be clearly observed; Some galaxies are very far away, and the farthest known galaxies are close to15 billion light years.

The word galaxy comes from the Greek Galaxis (γ α λ α ξ? α? ), in a broad sense, can be an operating system composed of countless star systems (including the stars themselves, of course) and dust (such as nebulae). Referring to our Milky Way, it is a huge system containing stars, interstellar gas, cosmic dust and dark matter, and bound by gravity. [1][2] Typical galaxies, from dwarf galaxies with tens of millions (10) stars to elliptical galaxies with trillions (10) stars, all have [4], and all revolve around the center of mass. Except for individual stars and thin interstellar matter, most galaxies have a large number of multi-star systems, clusters and various nebulae.

Galaxies are mainly divided into three categories: elliptical galaxies, spiral galaxies and irregular galaxies. A more explicit and extensive description of galaxy types will be described in the entries of Haber sequence. Because Haber's sequence is based on visual patterns, he may miss some important features of galaxies, such as star formation rate (at the core of starburst galaxies or active galaxies). Lens galaxy is a kind of galaxy between elliptical galaxy and spiral galaxy.

The formation and evolution of galaxies have always been controversial, some of which have been widely accepted, but many people still question them. The formation of galaxies includes two aspects, one is the upper and lower theory, and the other is the upper and lower theory. The upper and lower bound theory means that galaxies were formed in a big bang hundreds of millions of years ago. Another theory holds that galaxies are formed by a dust in the universe. Initially, there were many globular clusters in the universe. Later, these stars collided with each other and were destroyed, leaving dust behind. These dust particles combine to form galaxies.

Question 8: What does the constellation galaxy nebula mean? Nebula: It contains almost all expanding celestial bodies except planets and comets.

Galaxies: Celestial systems usually consisting of hundreds of millions to trillions of stars and interstellar matter, with spatial scales ranging from thousands to hundreds of thousands of light years.

Difference:

1. Galaxies are big substances * * *, while nebulae are small substances * * *, that is to say, they contain different amounts of substances, and galaxies are much larger than nebulae. From a geometric point of view, galaxies generally occupy a huge scale of tens of thousands to hundreds of thousands of light years, while nebulae are generally inside galaxies, with a scale of only a few hundred light years and rarely more than a thousand light years;

2. Nebulae exist in galaxies and are part of galactic matter;

Galaxies originated from nebulae, but the universe has survived to this day, and all the original nebulae have evolved into galaxies, so the present nebulae are all remnants of galaxies that have not yet evolved into stars, or secondary nebulae (planetary nebulae) ejected when stars die.