Know little about the universe

In natural science, astronomy is a basic subject to study the movement, structure, origin and evolution of various celestial bodies in the cosmic environment outside the earth. Its history can be traced back to the embryonic period of human civilization. In ancient times, nomadic people needed to identify the direction when they migrated by aquatic plants, and agricultural people needed to determine the season when they planted seeds on time. In the long-term practice year after year, they gradually discovered the close relationship between these major events affecting their lives and astronomical phenomena such as the sun, the moon and the stars. Babylonian clay tablets, Egyptian pyramids and Oracle Bone Inscriptions in China Yin Ruins all left rich examples of the birth of astronomy. Astronomy has always made great contributions to the progress of human civilization. /kloc-Heliocentrism of Copernicus liberated natural science from the shackles of medieval theology for the first time in the 6th century. The classical mechanical system established by Galileo and Newton in the17th century to study the laws of motion of celestial bodies in the solar system is still the basis of modern engineering science (including aerospace science). The research on the internal structure and energy of the sun and stars in the 1930s produced the concept of thermonuclear fusion, which provided enlightenment for human beings to use nuclear energy. Especially in the past half century, human's enthusiasm for exploring the universe, on the one hand, has strongly promoted the development of a series of high and new technologies such as telemetry and telecontrol, space technology and computing technology, and directly served the national economic departments such as global communication, resource investigation and weather forecast. The application of these technologies in astronomy has made people's understanding of the universe advance by leaps and bounds. For the first time, it can be explained from the unified principle, from elementary particles to chemical elements, from galaxies to stars, from the sun to the earth, from protozoa to humans, it is tens of billions.

The earth where we live is an ordinary member of the solar system. The central celestial body of the solar system is the sun, which is a gas ball with a radius of about 700,000 kilometers and a surface temperature of 6000K K. Its core temperature is as high as1.5,000 K, and a nuclear reaction of hydrogen fusion into helium occurs. The light and heat on which we live are produced by this nuclear reaction. There are nine planets in the solar system, namely Mercury, Venus, Earth, Mars, Jupiter, Uranus, Neptune and Pluto. The outermost Pluto is about 6 billion kilometers away from the sun. There are thousands of asteroids running between Mars and Jupiter. There are comets and meteors in the solar system.

There is a band of light across the sky in the clear night sky, which is called the Milky Way. In fact, it is a huge celestial system composed of stars and diffuse matter, called the Milky Way. The luminous part of the Milky Way is about 70,000 light years in diameter and 20,000 light years in maximum thickness, like a rotating discus with a flat protrusion in the center. The sun is an ordinary star in the Milky Way. There are about 200 billion stars in the Milky Way, which are far apart from each other. Proxima centauri, which is closest to the sun, is also 4.3 light years away, which is 60 million times the radius of the sun. In addition to stars, there are many gas and dust masses in the Milky Way, called nebulae. Some nebulae contain a large number of molecules, called molecular clouds, which are often the places where stars form.

Outside the Milky Way, there are1000 billion huge celestial systems, which belong to the same structural level as the Milky Way and are collectively called galaxies. Andromeda galaxy, the farthest celestial body visible to the naked eye, is one of them. It is 2.25 million light-years away from the Milky Way, but it is the nearest galaxy of the same size. The distribution of galaxies in the universe is uneven, some in pairs, some in groups, and large clusters of galaxies even contain hundreds of galaxies. Some galaxy clusters have gathered into larger supercluster, and no uneven signs have been found between more than 500 million light-years and 654.38+0.5 billion light-years observed so far.

You may have misunderstood the common sense of the universe.

1, starlight hundreds of years ago.

A lot of starlight we see now is the light emitted by that star hundreds of years later. Because of the long distance, it takes hundreds of years for a star to reach the earth.

2. The sunshine eight minutes ago. The sunshine we bathe in is actually the light from the sun eight minutes ago.

What a surprise! Actually, it's the same as above. The distance between the earth and the sun is about 65.438+0.49 billion kilometers, according to the speed of light propagation.

It takes more than 8 minutes for sunlight to travel from the sun to the earth. The moon is leaving us.

When Apollo successfully landed on the moon, astronauts at that time installed some mirror-like rangefinders on the moon. After that, scientists fired lasers at these mirrors from the earth in order to observe the moon, and measured the distance between the earth and the moon through the round-trip time of the laser.

The results show that the moon is about 3.8 cm away from the earth every year. The reason for staying away may be due to the continuous expansion of the universe.

4. A planet full of diamonds. That sounds tempting.

It seems that diamonds are scattered on the surface of the diamond planet, but it is actually a rocky planet. There is no water source on the surface of diamond planet, and its main components are carbon (graphite and diamond), iron, silicon carbide and undetermined silicate.

We know little about the universe. Despite the advanced science, we still know very little about the universe.

The stars that we can see with the naked eye only account for 5% of the universe. 6. Footprints that will not disappear.

In the last century, when man took a small step on the moon, that footprint was likely to stay there all the time. Because the moon has no atmosphere, and there are no traces of wind and water washing away the surface of the moon.

7. Interesting Venus. Venus takes 224 days to orbit the sun, but it takes 243 days to orbit itself.

In other words, a year on Venus is equivalent to 224 days on Earth, and a day on Venus is equivalent to 243 days on Earth. This also means that the days on Venus are getting longer and longer.

Moreover, Venus is the only planet in the solar system that revolves around the sun.

3. Knowledge about the universe

Cosmic knowledge 1. During the Western Zhou Dynasty in China, the process of human understanding of the universe, the theory of covering the sky put forward by people who lived on the land of China in the early days believed that the sky was like a pot, and it was upside down on the flat ground; Later, it developed into the later theory of covering the sky, which believed that the shape of the earth was also arched.

In the 7th century BC, Babylonians believed that the sky and the earth were arched, with the ocean around the earth and the mountains in the center. The ancient Egyptians imagined the universe as a big box, with the sky as the lid, the earth as the bottom and the Nile as the center of the earth.

The ancient Indians imagined that the disc-shaped earth was thrown on several elephants, and the elephants stood on the backs of huge turtles. At the end of the 7th century BC, Thales in ancient Greece thought that the earth was a huge disk floating on the water, covered with an arched sky. It was the ancient Greeks who first realized that the earth was spherical.

In the 6th century BC, Pythagoras thought that the most beautiful three-dimensional figure was spherical from an aesthetic point of view, and advocated that celestial bodies and the earth where we live were both spherical. This idea was later inherited by many ancient Greek scholars, but it was not until 15 19~ 1522 that F Magellan of Portugal led the expedition to complete the first round-the-world voyage that the idea that the earth was spherical was finally proved.

The research results of contemporary astronomy show that the universe is a celestial system with hierarchical structure, diverse material forms and continuous movement and development. Second, the hierarchical structure of the universe The planet is the most basic celestial system.

There are nine planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Uranus, Neptune and Pluto (at present, only a few scientists agree to expel them and make them dwarf). Except mercury and venus, all other planets have satellites orbiting them. There is one satellite on the earth, and the moon and Saturn have the most satellites, with 26 confirmed.

Planets, asteroids, comets and meteoroids all revolve around the central celestial body, the sun, forming the solar system. The sun accounts for 99.86% of the total mass of the solar system, with a diameter of about 6.5438+0.4 million kilometers, and the largest planet Jupiter has a diameter of about 6.5438+0.4 million kilometers.

The solar system is about 65.438+0.2 billion kilometers (bounded by Pluto). There is evidence that there are other planetary systems outside our solar system.

250 billion sun-like stars and interstellar matter constitute a larger celestial system-the Milky Way. Most of the stars and interstellar matter in the Milky Way are concentrated in an oblate space, which looks like a discus from the side, but from the front? It is in the shape of a vortex.

The diameter of the Milky Way is about 654.38+ million light years, and the sun is located in a spiral arm of the Milky Way, about 30,000 light years away from the center of the Milky Way. There are many similar celestial systems outside the Milky Way, which are called extragalactic galaxies, which is what we often call galaxies.

It is observed that there is about 10 billion. Galaxies also gather into large and small groups called galaxy clusters.

On average, each cluster has more than 100 galaxies with a diameter of tens of millions of light years. Thousands of galaxy clusters have been discovered.

A small cluster of galaxies consisting of about 40 galaxies, including the Milky Way, is called the local cluster. When several galaxy clusters gather together to form a larger and higher-level celestial system, this galaxy cluster is called a supercluster.

Supergalaxy clusters often have a flat shape, and their long diameter can reach hundreds of millions of light years. Usually, superclusters contain only a few clusters, and only a few superclusters have dozens of clusters.

A supercluster composed of the local cluster and about 50 nearby clusters is called a local supercluster. At present, the scope of astronomical observation has been extended to the vast space of 20 billion light years, which is called the total galaxy.

Third, the origin of the universe The thermal big bang universe model depicts the origin and evolution history of our universe: our universe originated from a big bang 20 billion years ago, when the temperature was extremely high and the density was extremely high. With the expansion of the universe, it has gone through the evolution process from hot to cold, from dense to thin, from radiation to material, and it did not enter the stage of large-scale galaxy formation until1~ 2 billion years ago, and then gradually formed the universe we see today.

Little knowledge about outer space 1. There are more than10 billion galaxies in the universe. The largest galaxy has nearly 400 billion stars, and our galaxy, the banking department, can definitely have 654.38+000 billion stars. If you want to count the stars, it will take you 3000 years to count them all. 2. The "sun" is the largest in the solar system, accounting for about 98% of the total mass of the solar system (the sun can fit into10.3 million earths, the surface temperature of the sun is 6000℃, and the internal temperature is as high as10.5 billion℃); 3. Jupiter is the largest planet in the solar system and the planet with the fastest rotation. It is only 9 hours and 55 minutes a day on Jupiter. Saturn is the second largest planet and the brightest star in the solar system. It has a low density and can float on the water. 5. In a vacuum-like space, two kinds of similar metals with clean and flat surfaces will be instantly bonded together, and they only need to be gently bonded together (this is cold welding, or contact welding); 6. Astronauts will not burp in space (because the gravity is too low, the gas in the stomach will not be separated from the liquid, so it is impossible to burp); 7. In outer space, flowing liquid will become spherical (this is due to the surface tension and low gravity of liquid); 8. In space, no one can hear your screams (because there is no air to transmit the sound waves of your screams).

4. A little common sense about space, introduce space.

The space outside the earth's atmosphere, the whole space outside the atmosphere.

Space physicists divide the atmosphere into five layers: troposphere (sea level to 10 km), stratosphere (10~40 km), mesosphere (40~80 km), thermosphere (ionosphere, 80~370 km) and outer atmosphere (ionosphere, more than 370 km). About 3/4 of the atmosphere above the earth is in the troposphere, and 97% is below the stratosphere. The outer edge of the stratosphere is the highest limit for an aircraft to fly with air support.

Some high-altitude rockets can enter the middle layer. The lowest orbit of the satellite is in the thermocline, and its air density is 1% of the earth's surface.

At the height of 16000km, air continues to exist, and even at the height of 10000km, there are still air particles. From a strictly scientific point of view, there is no clear boundary between airspace and outer space, but they are gradually integrated.

The Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space pointed out that it is impossible to put forward accurate and lasting scientific standards to divide the boundary between outer space and airspace. In recent years, people tend to take the minimum height of artificial satellites from the ground (100 ~110) km as the lowest limit of outer space.

5. Knowledge about the universe (2) (short)

Give you two important cosmological concepts: 1 and BIGBANG's theory. This theory is based on an idea of astronomical observation and research.

About 654.38+0.5 billion years ago, all the substances in the universe were highly concentrated at one point, with extremely high temperature, which led to a huge explosion. After the big bang, matter began to expand outward, forming the universe we see today.

The whole process of the Big Bang is complicated, and now we can only describe the history of the development of the ancient universe on the basis of theoretical research. In this/kloc-0.5 billion year, galaxy clusters, galaxies, our galaxies, stars, solar systems, planets, satellites and so on were born one after another.

Now all the celestial bodies and cosmic substances we see and can't see have formed today's cosmic form, and human beings were born in this cosmic evolution. 2. Black hole A black hole is a celestial body with strong gravity, and light cannot escape.

When the schwarzschild radius of a star is small enough, even the light emitted from a vertical plane cannot escape. Then the star becomes a black hole.

To call it "black" means that it is like a bottomless pit in the universe. Once anything falls in, it seems that it can't escape. Because the light in the black hole can't escape, we can't directly observe the black hole.

But its existence can be indirectly observed or inferred by measuring its effect and influence on the surrounding celestial bodies.

I want to use a little knowledge about the universe.

Outer space refers to the space outside the dense atmosphere of the earth, and there is no clear boundary. ordinary

It is defined as the space about 1000 km from the earth's surface. Human curiosity and exploration of outer space have never been

No, the successful launch of China's "Shenzhou 5" and "Shenzhou VI" indicates that China's exploration of outer space has gone global.

Advanced ranks in the world.

Outer space is referred to as space for short, also known as cosmic space, which refers to the outer atmosphere relative to the earth's sky.

Void area, outer space is usually used to distinguish it from airspace (territory); Although it is empty, it is not nothing.

Hmm.

There is no clear boundary between space and the earth's atmosphere, because the atmosphere gradually becomes thinner with the increase of height. wrong

Assuming that the atmospheric temperature is fixed, the atmospheric pressure will increase exponentially from 1000 mbar at sea level with the increase of altitude.

Reduce to zero

The height of 100 km is defined as the Carmen line by the International Aviation Federation, which sets the boundary between the atmosphere and space.

Justice. The United States recognizes that people who reach an altitude of 80 kilometers are astronauts. 120 during the spacecraft's return to Earth.

Kilometers is the boundary where air resistance comes into play.

7. Collect five simple things about space.

Space is an extremely cold environment with an average temperature of -270.3℃. In space, various celestial bodies also radiate electromagnetic waves, and many celestial bodies also radiate high-energy particles to form cosmic rays. For example, the sun has solar electromagnetic radiation, solar cosmic ray radiation and solar wind. Solar cosmic ray radiation is high-energy particles emitted by the sun when a flare occurs, and solar wind is a high-energy plasma stream blown out by the corona. Many celestial bodies have magnetic fields. The magnetic field captures the high-energy charged particles and forms a radiation belt with strong radiation. For example, there are two radiation belts above the earth. Therefore, space is still a strong radiation environment. Space is also a high vacuum and microgravity environment. Gravity is only 1% to1100000 g (g- acceleration of gravity), while the gravity felt by people on the ground is1g. Therefore, the * * spacesuit cannot be used by human beings.

8. There is little knowledge about the universe

Constellation division Aries: March 2 1 to April 20 Taurus: April 2 1 to May 2 1 Gemini: May 22 to June 2 1 Cancer: June 22 to July 22 Leo: July 23 to August 23 Virgo: Seats: 65438+1October 22nd Sagittarius:165438+1October 23rd to 65438+

As the earth revolves around the sun, from the perspective of the earth, the sun seems to move between constellations. People call the running route of the sun the ecliptic, and the running tracks of the moon and planets basically do not leave the narrow area of 9 degrees above and below the ecliptic, so people call this area the ecliptic. There were twelve zodiac signs in ancient times, and the sun basically passed one zodiac sign every month, so it was called the zodiac.

After the day, due to precession, the date when the sun passes through the zodiac is very different from that in ancient times. Introduction to Mercury Mercury is the closest planet to the sun, and its angular distance from the sun has never exceeded 28. In ancient China, Mercury was called a star.

In ancient times, Westerners thought that Mercury was two planets. When they see it at dusk, they call it mercury, and when they see it at dawn, they call it Apollo. Later, people knew that Mercury and Apollo were the same star, so they called Mercury Mercury.

Mercury was a messenger in Roman mythology who sent messages to the gods. He wears a hat with wings, flying shoes and a wand, and walks like a fly. He is omnipotent and unpredictable.

Mercury, like mercury, is really changing and elusive. In another month and a half, it will run from the easternmost end of the sun to the westernmost end, with an average speed of 47.89 kilometers per second, making it the fastest moving planet in the solar system. Venus is a simple introduction to Venus, which was called Taibai or Taibai Venus in ancient China.

It is sometimes the morning star, which appears in the eastern sky before dawn and is called "Qi Ming". Sometimes it is a dim star, which appears in the western sky after dusk and is called Chang Gung. Venus is the brightest star in the whole day except the sun and the moon, just like a dazzling diamond, so the ancient Greeks called it Aphrodite, the goddess of love and beauty, while the Romans called it Venus, the god of beauty.

In astronomy, the symbol of Venus is the precious mirror used by the beauty god when dressing. The earth is one of the nine planets in the solar system, and the third planet is arranged in the order from near to far from the sun.

It has a natural satellite-the moon, forming a celestial system-the earth-moon system. From near to far from the sun, Mars is the fourth planet.

To the naked eye, it is a striking bright lux star. It travels slowly among the stars. When looking at Mars from the earth, it sometimes goes straight and sometimes goes backwards.

The darkest apparent magnitude of Mars is about+1.5, etc. And at the brightest time, it is brighter than the brightest star Sirius, reaching -2.9. This is because the Earth and Mars are in their respective orbits, and the distance between them is always changing. Mars is as bright as fire, its brightness is constantly changing and its position is uncertain, which is confusing. So China called Mars "sparkling" in ancient times.

In western ancient Roman mythology, it was imagined as Mars, the god of war in armor and covered in blood, that is, Ares in Greek mythology. Ares had a noble life. His father is Zeus, the king of the gods, and his mother is Hera, the queen of heaven.

Astronomically, the symbol of Mars is the combination of the spear and shield of Mars. Introduction to Jupiter Jupiter is the most striking planet in the solar system. It is the oldest and largest of the nine planetary brothers.

Its brightness is second only to Venus. In ancient China, it was called the "year-old star", which was used to date the years because it was known that its period of revolution was close to 12.

The west calls Jupiter "Jupiter", the main god in Roman mythology. Equivalent to the king Zeus in Greek mythology.

Saturn is a beautiful planet, the sixth farthest from the sun. Anyone who has seen Saturn through a telescope will be surprised. Saturn's orbital radius is 65.438+0.4 billion kilometers, and its maximum brightness is 0.4 magnitude when it hits the sun.

On Saturn's orange surface, there are bright and dark clouds floating, and the soft and shiny halo on the equatorial plane looks like a girl wearing a sun hat from a distance. It is more than 6000 kilometers larger than the radius of the poles.

Saturn's period of revolution is 29.5 years, which is about 28 nights. It stays in the town for one night every year, so it was also called "Town Star" in ancient China. Saturn has always been regarded as the boundary of the solar system, and it was not until Uranus was discovered in 178 1 that the solar system began to expand.

Saturn moves slowly, so people regard it as a symbol of time and fate. In Roman mythology, he was called the Saturnalia, that is, Cronus in Greek mythology. He is the father of Zeus, the king of the gods, who overthrew his father and ascended the throne of the gods.

Both the East and the West associate Saturn with agriculture. Symbols in astronomy are like scythes that dominate agriculture.

Introduction to Uranus It is not difficult to watch Uranus on a clear night. Its magnitude is 5.7.

Its period of revolution is quite long. It orbits the sun once every 84 years, moving only 46 inches a day on average. It is not easy to distinguish it from a star. In history, it has been mistaken for many times that stars are loaded into star maps. Introduction to Neptune The average distance from the sun is arranged from near to far, and Neptune ranks eighth.

Its brightness is 7.85 and so on, which can only be seen in a telescope. Because it is a light blue planet, it is named Neptune according to the traditional planetary nomenclature.

Neptune is the sea god who rules the ocean in Roman mythology. He is in charge of the universe of13, which is quite amazing. Neptune's astronomical symbol symbolizes the cold shiny fork in Neptune's hand. Asteroids refer to small celestial bodies that are mostly distributed between the orbits of Mars and Jupiter and orbit around the sun along elliptical orbits.

180 1 year, Italian astronomer Piazi discovered a star in the position predicted by his predecessors, and later named it ceres. However, after further observation and calculation, it is found that Ceres is too small to be compared with the existing planets in any case, so Ceres is characterized as an "asteroid".

Then people discovered pallas Athena, Vesta, Vesta and other asteroids.

9. There is little knowledge about the universe

The universe is the general name of the vast space and all kinds of celestial bodies and dispersed substances existing in it.

The universe is a material world, which is in constant movement and development. Huai Nan Zi. Original note: "The four directions are called Yu, and from ancient times to the present, Zhou is called heaven and earth."

In other words, the universe is the floorboard of everything in the world. For thousands of years, scientists have been exploring when and how the universe was formed.

Until today, scientists are convinced that the universe was formed by a big bang about 654.38+0.5 billion years ago. Before the explosion, all the matter and energy in the universe gathered together and condensed into a very small volume with extremely high temperature and density, and then a big explosion occurred.

The big bang dispersed the matter, expanded the space and lowered the temperature accordingly. All the later galaxies, stars, planets and even life in the universe were gradually formed in this process of continuous expansion and cooling. However, the theory that the Big Bang produced the universe cannot accurately explain what existed before "stored matter and energy gathered at one point". The Big Bang theory was founded by Gamov in 1946.

It is the most influential theory in the modern cosmic system, also known as the Big Bang Cosmology. Compared with other models of the universe, it can explain more observational facts.

Its main point is that our universe once had an evolutionary history from hot to cold. During this period, the cosmic system is not static, but constantly expanding, which makes the density of matter evolve from dense to sparse.

This process from hot to cold, from dense to thin, is like a huge explosion. According to BIGBANG's cosmology, the whole process of BIGBANG was in the early universe, and the temperature was extremely high, above 1000 billion degrees.

The density of matter is also quite large, and the whole universe system is in equilibrium. There are only some elementary particles in the universe, such as neutrons, protons, electrons, photons and neutrinos.

But because the whole system is expanding, the temperature drops rapidly. When the temperature drops to about1000 billion degrees, neutrons begin to lose the condition of free existence, and they either decay or combine with protons to form heavy hydrogen, helium and other elements. It was from this period that chemical elements began to form.

When the temperature further drops to 654.38 0 million degrees, the early process of forming chemical elements ends. The substances in the universe are mainly protons, electrons, photons and some lighter nuclei.

When the temperature drops to several thousand degrees, the radiation decreases, and the universe is mainly gaseous. Gas gradually condenses into gas clouds, and then further forms various star systems, becoming the universe we see today.