Give me some scientific knowledge! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

The internal structure of the earth refers to the layered structure of the earth. Today, the probe can travel in the outer space of the solar system, but the earth under human feet is out of reach. At present, the deepest borehole in the world is only 12 km, and even the earth's crust has not penetrated. Scientists can only reveal the secrets inside the earth by studying seismic waves, geomagnetic waves and volcanic eruptions. It is generally believed that the earth has three concentric spheres: the core, the mantle and the crust.

The crust is the surface layer of the earth, and it is also the place where human beings live and engage in various production activities. In fact, the crust is composed of many groups of faults and many blocks of different sizes, and its exterior presents a undulating shape, so the thickness of the crust is not uniform: the average thickness of the crust below the mainland is about 35 kilometers, and the thickness of the crust on the Qinghai-Tibet Plateau in China exceeds 65 kilometers; The thickness of the ocean lower crust is only about 5 ~ 10 km; The average thickness of the whole crust is about 15 km, which is only a thin layer compared with the average radius of the earth of 637 1 km.

The upper crust is a granite layer, mainly composed of silicon-aluminum oxides; The lower layer is basalt layer, which is mainly composed of magnesium silicate. Theoretically, the temperature and pressure in the crust increase with depth, and the temperature increases 100 m 1℃. The drilling results in recent years show that the temperature rises by 2.5℃ per 100 m when the depth exceeds 3 km, and reaches 200℃ at the depth of 1 1 km.

Most of the known crustal rocks are less than 2 billion years old, and even the oldest rocks in Greenland, Denmark are only 3.9 billion years old. Astronomers have studied the earth for about 4.6 billion years. The research shows that the rocks in the earth's crust are not the original crust of the earth, but are composed of materials inside the earth through volcanic activities and orogeny.

Below the crust is the middle layer of the earth, called the "mantle", with a thickness of about 2865 kilometers. It is mainly composed of dense rock-forming materials and is the largest and thickest layer in the earth. The mantle can be divided into two layers: the upper mantle and the lower mantle. It is generally believed that there is asthenosphere at the top of the upper mantle, which is presumed to be caused by the massive accumulation of radioactive elements, exothermic transformation and rock melting, and may be the birthplace of magma. The temperature, pressure and density of the lower mantle increase, and the matter is in a plastic solid state.

Below the mantle is the core, with an average thickness of about 3400 kilometers. The core can also be divided into three layers: outer core, transition layer and inner core. The outer core is about 2080 kilometers thick, and the substance is liquid and mobile. The thickness of the transition layer is about140km; The inner core is a spherical center with a radius of 1250 km. This substance is likely to be solid, mainly composed of metal elements such as iron and nickel. The temperature and pressure of the core are very high. The estimated temperature is above 5000℃, the pressure is above1320,000 kPa, and the density is13g per cubic centimeter.

Scientists in the United States have calculated by experimental methods that the temperature at the junction of mantle and core is above 3500℃, the temperature at the junction of outer core and core is 6300℃, and the temperature of core is about 6600℃.

Surface change

In the early days of the earth's formation, when it cooled, the surface was Wang Yang. The subsequent orogeny formed land and mountains, and then life appeared. Life was born in the sea, after evolution, it landed on land, multiplied and evolved into many species. Coupled with various natural forces such as sunlight and weathering, the present surface is formed.

Is there life outside the earth?

In the galaxy1800 million planetary system, if 1% of the galaxies have the possibility of life, then the probability is greater than1800 million; In this1.80 billion, if 1% has living things, then the probability is1.80; 1.8 million, if 1% is an intelligent creature, then the probability is 1.8 million. If you count the galaxies outside the river, the probability will be surprisingly high. So the idea that "man is the only child in the universe" is naive and ridiculous.

Every starry night, we look up at the sky, and a galaxy crosses the sky. The Andromeda Nebula next to Polaris tells people stories that the ears can't hear. At this time, the myth of the Cowherd and the Weaver Girl, the legend of the Goddess Chang'e flying to the moon and the story of the Arctic fairy Weng have already surrounded our hearts. Following the ancient sound of Qu Yuan asking for heaven, we dare to ask the sky: Are there any relatives and friends in the vast expanse?

Are there any creatures in the universe besides stars? Are there any intelligent creatures as great as human beings? The universe did not answer! Is it acquiescence or disdain?

This can't be blamed on the great universe, but only on the small earth people, because before the universe answers, even before we ask questions, we already have a definite answer in our hearts, that is, the earth is the only child of the universe.

The view that the earth is the only seedling in the universe has existed since ancient times. You will not forget that in the Middle Ages, in the West, religious theology believed that the earth was the center of the universe, because Almighty God lived on it. Of course, this is not only a problem in the west, but almost all ethnic groups in the world have similar views. China people think that China is the center of the world, so it is called "China". In fact, everyone knows in their hearts that we are not really praising the greatness of the earth, but in another way to praise the greatness of mankind. "Everything in the world is only people." This is the most fundamental purpose. The concepts of "the earth is the center of the universe" and "man is the only son of the universe" have long been deeply rooted in people's hearts.

It is understandable to say that the above ideas stem from the backwardness of understanding, but the problem is that it seems to have nothing to do with people's understanding. In fact, until today, quite a few people still hold the same view. Modern science seems to have no intention of eliminating the concept of geocentric theory when it overturns superstition. On the contrary, many scientists are actively looking for evidence to prove the religious concept that human beings on earth are the only children in the universe. Therefore, the key lies in the arrogant nature of human beings.

However, no matter how carefully people maintain their fragile self-esteem, the development of science itself is crushing the already riddled self-esteem again and again, and people are being forced to accept the following facts:

Just as we see the world as a whole today, in fact, the whole universe is a perfect whole, and our earth and solar system are only a small part of this whole, which is almost negligible. Similarly, just as the political, economic and cultural development of countries can not be separated from the overall influence of the world, the existence and evolution of galaxies in the universe also influence each other. When our civilization is breaking through the gravity of the earth and moving towards the civilization of the universe, people are increasingly aware that in the whole universe, it is not only human beings who can consciously influence the development of the earth (the history of human influence on the earth is only 2 million years at most, accounting for only 1/2500 of the earth's time), and unexpected things are happening all the time in the vast universe. The birth and destruction of life are indispensable in the operation of the universe.

Let's first look at the probability of life in the universe: modern astronomy recognizes that there are about 300 billion stars in our galaxy, and there are at least 654.38+08 billion planetary systems. If only 654.38+0% of these planetary systems may have life, then this number is still huge, up to 654.38+08 billion. Similarly, if there is life in 1% of these planetary systems, then the number we get is still 1.8 million. Let's further assume that every 100 living planets, only shellfish are inhabited by creatures with the same level of intelligence as humans, so there are still as many as 18000 planets in our galaxy that may have advanced life. This is just our own galaxy. How many giant galaxies like the Milky Way exist in the middle of the universe? I'm afraid this is a terrible astronomical figure.

Therefore, it is naive and ridiculous to think that people on earth are the only intelligent creatures in the universe from the perspective of probability alone. There is no doubt that there are countless planets similar to the earth in the universe, with similar mixed atmosphere, similar gravity, similar plants and even similar animals. As early as the 4th century BC, the ancient Greek philosopher Mitterrand once said, "The idea that only the earth is inhabited in the boundless universe is as ridiculous as a seedling growing on the land where millet was sown."

1997, American biologists discovered an Archaean creature on the earth, which can survive in extremely cold or extremely hot environment. It has two characteristics of bacteria and all eukaryotes, including animals, plants and people, and is the third life form. The discovery of this creature proves that human understanding of life characteristics is not enough. Please don't forget that this is only in the environment of the earth, in the middle of the vast universe, the form of life is more complicated. It is the most undesirable way to evaluate the existence of cosmic creatures from the perspective of geo-biology. Nasa recently announced that it has discovered a new planet orbiting the Porel Lisi star near the earth, which is about the size of Jupiter, the largest planet in the solar system. The newly discovered planet is 37 million kilometers away from the star, which is 1/4 of the distance from the earth to the sun, even closer than the distance from mercury to the sun. Its surface temperature is estimated to reach 200℃-260℃. At this temperature, it is difficult for life on earth to survive, but there may be high-temperature resistant life in the universe. The discovery of this planet has strengthened people's confidence that there are probably a large number of living planets in space.

1969, the right asymmetric amino acids that could not be naturally formed on the earth were found in the carbonaceous chondrite falling in Australia, indicating the possibility of life outside the earth. Just recently, NASA announced that photos taken from the Hubble Space Telescope show that Jupiter, which has always been considered unstable, has been found to have an atmosphere and moist soil, which shows that Jupiter already has the basic conditions for life. 1996, NASA discovered from a Martian meteorite from Arizona, USA that there were ancient microorganisms in this meteorite, and the ancient legend of life on Mars was once again taken seriously.

1963, scientists discovered the spectrum of the organic molecule formaldehyde in Sagittarius with a radio telescope, which is of great significance. Because organic formaldehyde molecules can be converted into amino acids, and amino acids are the basic components of life. The discovery of organic formaldehyde molecules proves once again that life on earth is by no means a unique phenomenon in the universe, and human beings should not be the only child in the universe.

More and more discoveries point out a direction for us: life does exist in the universe, and even the most familiar life forms may be produced in a corner of the universe. The problem now is not to prove the existence of these lives, but to find them.

In 1970s, the United States took the lead in launching "Voyager 1" and "Voyager 2" in order to find possible life forms in the vast universe and have a dialogue with them. At this time, two spaceships are flying into outer space at the speed of 17.2 kilometers per second. 1986, when they passed Pluto, they flew out of the solar system and became real cosmic planets. If nothing happens, they will fly to another galaxy outside the solar system in 6.5438+0.47 million years and 555,000 years respectively.

Voyager has a bronze gold-plated record, which records the characteristics of our earthlings, the face of the earth and the greetings of former US President Carter to alien civilizations. The former president of the United States wrote in his letter: "We send this message to the universe. After 65.438 billion years, when our civilization has undergone profound changes and the face of the earth has undergone tremendous changes, this information may still exist. Among the 300 billion stars in the Milky Way, some (perhaps many) stars and planets are inhabited and there is a distant cosmic civilization. If such a civilization intercepts Voyager and can understand its recorded contents, please accept our following message ... "Obviously, Voyager was launched in search of extraterrestrial civilization. In other words, Americans assume that extraterrestrial civilization exists.

1994, when comet shoemaker-levy hit Jupiter, scientists found that a lot of water vapor appeared during the impact, which indicated that the comet had a lot of solid water. Where there is water, there is life. Comet Shoemaker-Levy is a very common comet in the universe. They travel across the universe, and there is a great possibility of life.

In fact, the problem is not just here. What kind of natural environment does life need? Is it necessary to have natural conditions similar to the earth? Is the biological view of the earth universally applicable to all the planets in the universe? Facts have proved that the view that life can only exist and develop on a planet like the earth is untenable.

There are more than 2 million kinds of living things on the earth. Among the 6,543.8+200,000 known species, there are more than 9,000 kinds of wells that do not need the general natural environment. In his book Car of the Gods, ehrlich Dunken introduced the experiments made by entomologists Hinton and Bloom of Bristol University. The two scientists baked an midge at a high temperature of 100℃ for several hours, immediately put it in liquid nitrogen (temperature is 270℃), and after intense irradiation, they put these experiments back into the normal living environment. These midges quickly regained their vitality and produced healthy offspring. This experiment fully shows that it is wrong to say that life can only exist under the conditions of the earth.

According to the biological viewpoint of the earth, sunlight, moisture and oxygen are the three elements of life. However, people have found creatures that don't need sunlight and bacteria that don't need oxygen under the seabed and the Arctic ice. They are called anaerobic bacteria. Many years ago, it was reported that people found frogs that had been sleeping for tens of thousands of years from completely closed rock formations. Under normal natural conditions, they actually regained their vitality. Life is incredible. Its tenacity is beyond people's imagination. With the deepening of our understanding, we found many lives in completely unexpected environments. For example, there is life around highly radioactive nuclear materials.

Now, more and more people believe in the existence of "extraterrestrial civilization", and they are likely to evolve dozens or even hundreds of times earlier than us. Today, we can not only land on the moon, but also explore the whole solar system. Then, a civilization many times more developed than ours, it is entirely possible for them to explore across galaxies, leave some remains and impart some knowledge in contact with our ancestors. Under this thought, the "ancient contact theory" came into being.

The founder of ancient contact theory is Ford Childs Hou of the United States. Throughout his life, he tirelessly collected data and information that could overthrow popular theories and put forward the slogan "Let science be liberated from the monopoly of scientists". His basic idea is that there are huge creatures in the universe, and for these creatures, the size of our world is only between the feeding box and the laboratory. He even said, "I guess we are the private property of some creatures." I think the earth originally didn't belong to anyone, and later it was investigated as a colony. "

Three good answers, right? Give me extra points. Thank you.