The sun has been burning for 5 billion years. When it goes out, what will be the fate of the earth?

Before humans stepped out of the earth, our knowledge of the sun was limited. But after humans stepped out of the earth and had more advanced detection equipment, our understanding of the sun continued to improve. Now we know the structure of the sun and its burning mode is nuclear fusion.

It is precisely because we have more knowledge about the sun that we also understand that the sun has a lifespan. Its lifespan is determined by the amount of hydrogen burning required for internal nuclear fusion. When the hydrogen inside it is burned and consumed, the life of the sun also enters the final stage. According to scientists' observation and research, the solar system has been burning for 5 billion years, and in about 5 billion years, its life will come to an end. What will be the fate of the earth when it goes out?

If we want to know the fate of the earth when the sun goes out, we must first have a simple understanding of the nuclear fusion process inside the sun. The nuclear fusion mode inside the sun is hydrogen-helium fusion, which consumes hydrogen and fuses it into helium element. This transformation process can continue for another 4 billion years, which means that the hydrogen element can still burn for 4 billion years.

After the hydrogen element inside the sun is exhausted, it does not mean that the sun will go out immediately. At this time, although the hydrogen-helium fusion reaction inside the sun has stopped, another fusion conversion process has begun, that is, the fusion conversion of helium element into carbon element. After the fusion of hydrogen nuclei inside the sun stops, its core will shrink and the temperature will continue to rise. At the same time, the outer layers of the sun will continue to expand. At this time, the sun will become a red giant.

When the core temperature rises to 100 million degrees, helium will be ignited, and then fused to produce carbon. This combustion and transformation process will last for about 1 billion years. Finally, when all the helium in the sun is converted into After the carbon, the Sun will eject its outer shell to form a planetary nebula, while the core will collapse and eventually form an Earth-sized white dwarf with a density of up to 10 tons per cubic centimeter. The sun is of medium mass and cannot explode as a supernova to form a neutron star or a black hole. It can only form a white dwarf star, which is the final destination of the sun.

Many people may read this and think that the sun still has 5 billion years of life, so the time left for the earth and humans is only 5 billion years. But in fact, the sun really has 5 billion years left for the earth and humans. The time is much less than this number. Many people also believe that the sun will only seriously threaten the survival of the earth and mankind when it transforms into a red giant, and the sun may need to wait 4 billion years for its expansion, which is when its internal hydrogen fusion reaction stops. .

But in fact, before the sun expands, it can already seriously threaten the survival of the earth and mankind. This is because as the hydrogen element in the sun is about to be exhausted, although the sun has not yet become a red giant, expansion, but the brightness and temperature of the sun will show a rapid upward trend. At this time, the earth's atmosphere may also be stripped off by the super strong solar wind.

Without the protection of the atmosphere, the water on the earth's surface will gradually evaporate. Without the atmosphere and surface liquid water, could life on earth and humans survive? The answer is no. At that time, if humans wanted to survive, they could only leave the earth and live temporarily on Mars. This situation occurred about 1.9 billion years ago.

So, the life of the sun seems to be 5 billion years, but the real time left for the earth and humans is less than 2 billion years. After 2 billion years, the meeting between the earth and mankind will truly begin. What kind of fate will that be?

If the earth is a planet without intelligent life or a planet with less developed technology, then we will have no choice but to passively accept the destruction in the face of the disaster caused by the great change of the sun. Not only will the earth be destroyed, but all life on the earth will also disappear with it.

However, according to the current speed of human science and technology development, 2 billion years is enough time for human science and technology to achieve several qualitative leaps. At least there is no problem in realizing preliminary interstellar immigration. We can no longer stay on the earth and the solar system. We can also take spaceships to other galaxies and live on other planets.

In addition to the method of immigrating to exoplanets, there is another method that does not require leaving the solar system, and that is to use powerful technological power to artificially intervene in the sun to extend its lifespan indefinitely. The reason why the sun will reach the end of its life is because the hydrogen required for nuclear fusion inside it will become less and less and will eventually be consumed.

If we can fill the sun with sufficient hydrogen through technology, can we save the sun? Theoretically it is certainly possible, but in actual operation we have to face many problems. After the hydrogen in the sun is burned out, it is possible that the sun will not be resurrected by filling the interior with a large amount of hydrogen. It may also require other technologies, such as extracting a large amount of helium from the interior.

In any case, The fate of the sun in the future is closely linked to the fate of the earth and mankind. We can only work hard to develop science and technology. When technology becomes powerful to a certain extent, we will be able to have more advanced technology to change the fate of the sun, the earth and mankind. It is not entirely unreasonable that technology is the most powerful force in the universe.