What happens when the Sun dies and devoures the Earth?

Before the Sun was fully expanded and turned into a giant red star, human descendants may have migrated to other planets like Neptune.

According to Live Science, a star begins to form with the accumulation of gases, mainly hydrogen and helium and some other elements. Gas molecules have mass, so if more gas accumulates, they will collapse under their own gravity.

This process creates pressure inward from a primitive star (protostar), heating up the gas so that only gas atoms remain in the form of plasma. Then, every two hydrogen nuclei will join together in the fusion reaction, forming a helium atom, releasing energy in the form of heat and light, while creating an outward pressure, prevent further collapse.

The image of the Sun shot on April 13, after 4.5 billion years of continuous fire.So far the Sun has finished about half its life.(Photo: NASA).

This helium fusion reaction will last for billions of years. By the time most of the hydrogen fuel was in the star's core, it no longer emitted much more energy, and began to collapse under its own weight. However, the collapse process now does not have enough pressure to combine hydrogen helium nuclei before. The star will still shine because the small amount of hydrogen on the core surface continues to produce energy.

The star's helium core in the process of collapse does not have enough energy to cause a nuclear fusion reaction as before, but because it is a compression process, the temperature continues to increase. The star now even frees more energy in the form of heat and light. However, energy also causes the star to expand, becoming a red giant. Red means that its surface temperature is lower than the previous nuclear reaction period. The Sun is currently emitting white light, the temperature is much higher than red light.

A 2008 study by astronomers Klaus-Peter Schröder and Robert Connon Smith estimated that when it became a giant red star , the Sun's surface would expand to about 170 million kilometers, swallowing Mercury, Venus and Earth. The process of becoming the Sun's giant star will last about 5 million years.

However, the Sun is about 10% brighter every 1 billion years. Therefore, the region may exist around the Sun, ie the appropriate distance for planets that exist on liquid surfaces will also be extended.

This region is currently at a distance between 0.95 and 1.37 times the Earth's orbital radius (also known as the AU astronomical unit). When the Sun becomes a giant red star, Mars will be in the area of ​​life at a certain time. The Earth will now be outside the living area and will be "baked" , the oceans evaporate, the water decomposes into oxygen and hydrogen.

Hydrogen is light so it will escape into space, and oxygen will react with rocks on the Earth's surface. Nitrogen and CO ₂ will be the major components of the atmosphere, like the current Venus. Human descendants will then migrate to Mars or find life outside the solar system.

The Sun will swell into a giant red star, swallowing the planets near it, including the Earth.(Photo: Paul G.Beck).

However, Mars is also only in the region of life for some time. By the time the Sun became a giant star, the area of ​​life would be in the range of 49–70 AU astronomers. Neptune with the current trajectory may become too hot, unable to live. A suitable place could be Pluto or dwarf planets, comets and ice-asteroids in the Kuiper belt.

One effect noted by Schröder and Smith is that stars like the Sun lose their mass over time , primarily through the dispersion of the solar wind. Therefore, the orbits of the planets will gradually expand. Earth's orbit will expand not fast enough to avoid perdition but Neptune may become a new home for humankind.

After becoming a giant star, the Sun will have to undergo a second collapse and cause a nuclear fusion. In about two billion years, the Sun will synthesize carbon and oxygen from helium, but this synthesis does not release as much energy as before. When the helium is gone, nothing can stop the Sun's shrinking process. Its core will be reduced to a white dwarf . The link between the core and the outer shell will be very weak, the shell will become a planetary cloud.

Because white dwarfs are heated by gas compression rather than thermonuclear reactions, their temperatures will be very high, with surface temperatures reaching 28,000 degrees Celsius and it will light up the nebula gas region .

However, the time until the Sun becomes a red giant is very long, at least 7 to 8 billion years. People live only 40 thousand of the total time. If the age of the Earth is 24 hours, the human being will only be present for a maximum of one second.