4 million tons per second! The speed at which the sun loses mass.

Our sun has gone through 4.6 billion years. In this long time, it has been constantly emitting light and heat, which has provided a guarantee for the evolution and survival of our life on earth. In the core of the sun, violent nuclear fusion reactions occur all the time. Hydrogen nuclei condense into helium atoms and then release positrons, neutrinos and photons. These released particles are light and heat from the sun. In the process of releasing particles, the sun will also lose great mass.

According to scientists' calculations, the sun will lose 4 million tons of mass every second, which is equivalent to the mass of an asteroid with a diameter of 1 1 km. If such a large asteroid directly hits the earth, the released energy will bring devastating damage to the earth. However, this mass is insignificant for the sun whose mass is 330 thousand times that of the earth. In the past 4.6 billion years, the sun has only lost about 100 earth, which is only about 0.03% of its own mass.

So according to this calculation, can our sun continue to emit energy for about 1 trillion years? Of course, not that long. The sun is a yellow dwarf. The life span of a yellow dwarf is about 654.38+000 billion years. That is to say, after about 5-6 billion years, the hydrogen in the sun will be exhausted, and the helium nucleus will collapse to resist gravity, leading to an increase in temperature. Then, the helium fusion reaction will begin, and helium will be condensed into carbon. The temperature will continue to rise and the outer layer of the sun will begin to expand. In this process, the sun will become very huge, the radius is about 200 times that of the present, and the surface can be extended to the vicinity of the earth's orbit.

After the red giant stage, the gas in the outer layer of the sun will escape due to strong thermal pulsation, forming a planetary nebula. After the outer layer is peeled off, it will leave a hot core, which is a white dwarf. In the next few billion years, it will gradually cool and darken, which is the final destination of our sun.

And our earth, did it still exist at that time?

As the mass of the sun decreases, the attraction between the earth and the sun will decrease, which means that the earth will be farther away from the sun? Scientists have indeed done research in this field. They launched a probe named Messenger to study the nearest planet to the sun-Mercury. After four years of investigation and a large number of orbital data, scientists have come to the conclusion that the loss of solar mass will increase the planetary orbits at the rate of 1.5cm/yr/au, that is, our earth will increase at the rate of 1 every year. After 5 billion years, it is still unknown whether our earth will be far away from the sun or swallowed up by the red giant sun.

It is hard to say whether the earth exists, but at that time, the earth was no longer suitable for life. At present, the brightness and temperature of the sun are rising. After about 1 100 million years, the earth is likely to become too hot for water to exist on the surface of the earth in liquid form. At that time, the earth will no longer be suitable for life. Where are we going? Have we found a livable planet suitable for interstellar migration, or have we disappeared in the long river of history?