According to astronomers, the sun is a yellow dwarf.
Yellow dwarf is a kind of star, the surface temperature is between 5300K and 6000K, and it belongs to the existence of medium-sized stars.
The lifespan of a yellow dwarf is about 10 billion years, and about 4.57 billion years have passed since the birth of the sun.
In other words, the life of the sun is only more than 5 billion years left.
Why can scientists accurately determine the life span of the sun? This is related to the formation and formation of the sun.
The sun comes from clouds of hydrogen molecules floating in the universe. This is a rather long process that takes hundreds of millions of years.
The hydrogen element inside undergoes a nuclear fusion reaction under tremendous pressure and burns into the sun, emitting a large amount of radiation and high-energy particles to the surroundings.
What makes people wonder is, since the light and heat of the sun belong to “nuclear radiation”, why are we not affected by radiation while living on the earth?
Nuclear radiation is divided into fusion reaction and fission reaction. Fission reaction is the radiation produced by the explosion of a nuclear bomb that we are familiar with, and it is very harmful to the human body.
However, the radiation range of the fusion reaction has little impact and is very stable. It is an inexhaustible clean energy source. We, who are far away in the habitable zone, will naturally not be harmed by radiation.
Of course, nuclear fusion is not always possible. When the hydrogen element of the sun is completely transformed, the life of the sun will also come to an end.
Therefore, scientists can estimate the lifespan and birth time of the sun by analyzing the helium and radioactive elements inside the sun.
Human beings can also more accurately grasp the time node when the sun goes out.
Theoretically speaking, the sun will not go out suddenly one day, but a gradual process.
As the hydrogen element inside the sun becomes less and less, the mass will become lighter and lighter, and the gravitational influence on the eight planets will also weaken.
Data show that the sun can convert 4 million tons of matter into energy through nuclear fusion reactions every second.
Since the birth of the sun, the sun has lost about 5.96*10^24 kilograms, which is equivalent to 100 times the mass of the earth.
In the next 5 billion years, the orbit of the earth will approach the boundary of the solar system. It is estimated that in 4 billion years, the orbit of the earth will be between the current earth and Jupiter.
After 1 billion years, the sun will go out and become a red giant star.
A red giant star is much larger than the sun, and very bright, but less luminous and hot than the sun.
Scientists speculate that there are two fates for the earth. If the tidal force of the earth and the sun disappears by then, the earth will be able to escape to a place about 1.7 astronomical units away from the red giant star and continue its revolution.
If the tidal force is still there, the fate of the earth will be engulfed by the photosphere of the red giant star and become a piece of material of the red giant star.
We can assume that the fate of the earth is the former. If it continues to revolve around the red giant star formed by the sun, what will happen to the earth?
After the death of the red giant star formed by the sun, due to the lack of internal mass, there is a high probability that a white dwarf may form.
The surface temperature of the white dwarf is extremely high, close to twice that of the sun, so the earth may become drier than Mars by then.
However, at this time, the earth’s atmosphere has long escaped into space, and it is no longer suitable for human habitation, and humans are no longer on the earth.
White dwarfs cool down over tens of billions of years to become black dwarfs.
Black dwarfs neither emit light nor have heat. If the earth is still there, it will become extremely cold. By then, the surface temperature may be lower than minus 200 degrees Celsius.
For such a long time, the earth may have been fragmented and become part of the cosmic dust.
Therefore, the earth cannot escape the fate of destruction in any case, but the development of human beings has infinite possibilities.
Long before the sun became a red giant, humans may have found a new home!
However, there is another question that makes everyone extremely curious, that is, what will happen if the sun suddenly turns off today, regardless of the evolution of stars?
Within an hour of turning off the lights, the earth will be plunged into darkness, solar street lights on the ground will light up, and people will panic.
At this time, the insulating effect of the atmosphere is still obvious, and the earth will not immediately become icy, which has no practical impact on people.
The governments of various countries will call on people to remain calm and start to solve the problem, but in fact, judging from the current technological means of human beings, there is basically no solution.
About 3 hours later, a series of new energy power plants such as hydroelectric power and wind power will no longer supply power, and people are in a panic about using electricity.
The country will also transfer backup energy to the hands of the people to maintain the most basic life.
At this time, friends may ask, the sun is gone, and plants cannot perform photosynthesis. How long will the oxygen on the earth be enough for us to absorb?
Don’t worry about this problem, the oxygen on the earth can supply us to breathe for a long time, plus artificial oxygen supply, it can sustain people for at least 100 years.
About 24 hours after the sun is turned off, the greenhouse effect will weaken, the temperature of the earth will gradually decrease, and people’s demand for energy will be greater.
Some countries may go to war over energy.
At the same time, the panicked people may trigger a series of crimes, and criminals will become more rampant in the dark.
A week later, the temperature in most parts of the earth dropped to 0 degrees Celsius, and people shivered in the cold wind.
Although there is still energy available at this time, people have gradually fallen from panic to despair. People’s riots are frequent, and it is difficult for countries to control.
After about 2 weeks, as the plants die, a large number of herbivores die, and at the same time the biological chain is severely damaged, and all animals will die in a short time.
At this time, various countries realized that the ground is no longer suitable for human survival, so they led their citizens to migrate underground.
About a year later, the surface temperature of the earth will be as low as minus 70 degrees Celsius, and human beings can only live underground, relying on the most primitive way to keep warm.
As the surface of the earth becomes colder and colder, the temperature will gradually spread to the ground. In order to cope with this temperature, human beings can only continue to move to the center of the earth.
With no source of light and heat, the temperature on the Earth’s surface would drop to close to absolute zero.
Until many years later, human beings could no longer dig the soil, and then the low temperature swept in from behind. Under the extreme cold and heat, they finally went to perish.
This process may take 5, 10 or even 15 years, and human beings as the overlord of the earth will become history.
It is worth noting that the big trees on the surface are still very hard. Although they have no leaves, they can survive in harsh environments for at least 20 years.
In about 1000 years, the temperature of the earth’s core will also be affected, and the ocean has long been frozen into a sea of ice, and the earth has become a frozen planet
After losing the gravitational effect of the earth, the earth will wander in space, and the earth will most likely wander to the Alpha Centauri galaxy, which is the closest star galaxy to us.
This process takes about 40,000 years.
At this time, the earth with light and heat ushers in “spring”, the ice and snow melt, and some tenacious microorganisms may recover.
The earth may give birth to new life again because of these microorganisms, and the cycle goes on and on.
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