Four billion years ago, there were three earths in the solar system? It is a miracle that scientists find human survivors.

The earth is the only planet in the whole universe where life is born. Humans are constantly exploring the universe and trying to receive signals from extraterrestrial civilizations, but no signs of life have been found on other planets. Is the earth the only planet in the universe that breeds life? If so, isn't the earth too lonely? But if there are other intelligent life in the universe, where will they be? We know that as long as there is liquid water, moderate temperature, atmosphere and sunshine, life can flourish. Interestingly, scientists found that there were "three earths" in the solar system 4 billion years ago! Why are we alone? Please look down.

In fact, there are many planets with this condition in the universe, such as Kepler 452b, gliese 58 1d, proxima b and so on. They are all rocky planets in livable areas, and intelligent life is likely to be born on these planets. However, due to the distance, we don't know the actual situation on the surface of these planets. At present, limited by the level of human science and technology, no extraterrestrial life has been found so far.

In addition, there are a large number of interstellar organic molecules in the vast space, which are absorbed by many rocky planets, so the formation of life is not lacking in nutrition. There are also some extremely tenacious primitive microorganisms, even in the cross star space. They can fly to other suitable planets to survive and multiply, just like scattered dandelions, spreading around to survive and multiply. Just like a veteran colonist, there may be alien creatures under the surface of Mars. For example, in the deep sea under the ice sheet on the surface of Europa, Callisto and Titan, there may also be marine life similar to the deep sea of the earth.

There may be many kinds of life in the whole universe, but there may be few species that can create civilization, because life is a very complicated process and will encounter many uncertainties, while life species like the earth have provided it with billions of years of development time, which is also very rare. Although the earth has experienced several mass extinctions, biological species are still developing in various forms, so it is very difficult to form highly intelligent biological species. Because the level of human science and technology is relatively backward, we don't know the situation in the depths of the universe.

Humans may be more advanced than us. To confirm this view, scientists have been sending probes into space. According to a large number of detection data, the final conclusion is that four billion years ago, there were three earths in the solar system, and life may have been born on them. Our present earth is one of them. The surfaces of these three planets are composed of solid metals and silicates, which belong to the study planet. In the past few decades, we have sent many unmanned probes to Venus and Mars, and scientists have found that their environment is extremely harsh.

Venus is very hot, but Mars is very cold and there is no oxygen. At least in this environment, scientists have not found any traces of other life. So what will Venus and Mars look like 4 billion years ago? Why has it become a barren planet now? Is there only one planet suitable for survival? According to the radiation intensity of sunlight, they all operate in a livable environment similar to the earth. According to the current signs on Venus and Mars, astronomers speculate that Venus and Mars may have an ocean of liquid water 4 billion years ago.

In the first few years, Venus was a warm and humid planet. Life can be born in the primitive ocean. They may be carbon-based life, like life on earth, or other life forms. But Venus is close to the sun, and it will produce a lot of liquid water. As the temperature of the sun rises gradually, Venus becomes hotter and hotter and is evaporated. The volcanic activity of Venus continuously releases carbon dioxide, which has a strong greenhouse effect. Without the action of the ocean, carbon oxides would not be locked. They enter the air and cause obvious global warming, which makes the temperature on Venus higher and higher.

On the earth, the deep sea, green plants and their minerals absorb a lot of carbon dioxide, so the earth is not easy to heat up due to serious global warming. In the end, liquid water will be completely evaporated on Venus, and the life species that are likely to exist will also perish. Although there can be no life on the surface of Venus, scientists believe that there are some strange life, which may exist in the atmosphere of Venus. In the relatively high air of Venus, with moderate atmospheric pressure and temperature, organic compounds may be born, life may evolve, or it may be a livable planet.

At present, there are many traces of the landform on Mars washed away by water, and some iron ores can only be produced in an environment with water. All these evidences can prove that there was a lot of liquid water on ancient Mars. So how did Mars become no longer suitable for species to survive? At present, there is a huge basin in the north and polar regions of Mars, and its area is equivalent to 2/5 of the surface area of Mars, which was caused by a big collision.

The study of this huge basin shows that about 3.9 billion years ago, the North Pole of Mars was hit by a dwarf planet with a diameter of about 2,000 kilometers, and the core of Mars was completely changed in this big collision, resulting in the almost disappearance of the magnetic field of Mars. Mars atmosphere is not protected by magnetic field, and liquid water disappears with continuous volatilization, and Mars soon becomes a barren land. At present, there is almost no atmosphere on Mars, but some water ice remains in the polar regions.

In addition, some seasonal liquid water may appear in some areas of Mars. This kind of water has a high salt content and can temporarily remain liquid in the low temperature environment of Mars. The average temperature on Mars is minus 63 degrees Celsius, and the temperature is extremely low. In the future, if human beings want to immigrate to Mars, they must first restore the magnetic field of Mars, generate a large amount of greenhouse gases to heat Mars and melt the solid water on Mars. Mars will be much smaller than the earth, and it will cool down from the molten state faster than the earth, so liquid water on Mars may appear earlier, which indicates that life on Mars may evolve earlier.

Based on this, it is speculated that when Mars is hit by other celestial bodies, the blasted rock layer is likely to bring Martian life into outer space and become the origin of life on earth after falling to the earth. In addition, in Martian meteorites, scientists have found traces of life, once again proving that Mars is the birthplace of life on earth. But the evidence is far from convincing. At present, Curiosity has detected carbonaceous organic matter in some rock formations on Mars.

This means that there was life on ancient Mars, and even today there is likely to be life on Mars. Billions of years ago, they did not go extinct, but moved to the underground of Mars and evolved a unique survival system. Compared with Venus and Mars, our earth has always been favored by nature and has always been a livable planet. In the future, the earth may no longer be as habitable as Venus and Mars. My friends, what do you think?