The sun nourishes the earth and makes the earth full of vitality. Our sun has been burning for about 5 billion years. Scientists predict that the lifespan of the sun is about 10 billion years old. This shows that the sun is now in its middle age and the most stable period. For th

The sun nourishes the earth and makes it full of vitality.

Our sun has been burning for about 5 billion years. Scientists predict that the lifespan of the sun is about 10 billion years old. This shows that the sun is now in its middle age and the most stable period. For the earth and humans, we are very lucky. of.

But even the sun will one day die due to exhaustion of fuel. This process is very tragic. Although that will happen in the very distant future, human civilization must prepare in advance.

As the fuel gradually decreases, the sun will slowly expand and move toward a red giant step by step. At present, it is difficult for us to feel the expansion of the sun, but as time goes by, the expansion rate of the sun will become faster and faster.

In about 3.5 billion years, the sun will completely expand into a red giant, expanding to the orbits of Mercury and Venus, completely swallowing these two planets, and the earth may also suffer.

Even if our earth is not swallowed by the sun, the earth will not be suitable for life by then. During the expansion of the sun, the brightness will increase significantly, the temperature of the earth will rise significantly, all the oceans will evaporate, and the earth will become a dead planet.

What about humans? If we want to continue human civilization, it means that we must leave the earth and find a second home.

Astronomers have been looking for other planets suitable for human habitation. At present, Europa and Enceladus are very promising to become human immigrants in the future.

Because as the sun expands into a red giant, the habitable zone in the solar system will gradually move outward. The earth is currently located in the golden zone of the habitable zone of the solar system. However, after billions of years, the habitable zone will move outward to the vicinity of Jupiter and Saturn . By then, the satellite families of Jupiter and Saturn are likely to become more habitable and become the "second" Earth.

Saturn and its satellites have a large number of satellites. Among these satellites, Europa and Enceladus have the highest "mass".

Through continuous detection, astronomers have discovered that although the surface temperatures of Europa and Enceladus are very low, there is very abundant seawater under the ice layer, and the total amount of seawater is much more than the total amount of seawater on the earth. With liquid water, life is very likely.

At the same time, although Europa and Enceladus have no magnetic field protection due to their small mass, their "big brothers" Jupiter and Saturn have super strong magnetic fields that can protect their "little brothers" Europa and Enceladus from Invasion of strong cosmic rays.

After the sun expands into a red giant, it does not mean that the sun will die immediately. It is a long process, up to a billion years later.

So after Jupiter and Saturn become the habitable zone, it means that humans have enough time to thrive on the moons of Jupiter and Saturn.

Of course, humans today do not need to worry about such a distant future, but this does not mean that the earth is absolutely safe. The beauty we feel about the earth is only superficial. Any unexpected event may cause human civilization to suffer a serious blow, or even come to an end.

For example, environmental deterioration, internal crises of mankind, violent cosmic events (such as supernova explosions, asteroids hitting the earth), etc., may cause devastating blows to the earth and mankind.

This is why astronomers have been working hard to find other habitable planets. Maybe there is no need for humans to immigrate to other planets for the time being, but we must be prepared in advance!