The history of our solar system began about five billion years ago; Today, the Sun is a middle-aged star, which scientists estimate that half its life has elapsed. This means that our star has another five billion years ahead of it, before it cools forever, also freezing all life on Earth, and disrupting the structure of the eight planets and other bodies that orbit around. to the.
In about five billion years, the Sun will exhaust the fuel that allows it to continue generating energy, which reaches Earth in the form of light and heat. This energy is produced by a process we know as nuclear fusion (on Earth, we use a ‘sister’ process, nuclear fission, to generate energy). The Sun continuously fuses hydrogen atoms in its nucleus to give rise to helium, as if it were a machine that does not stop working. This is how the engineering of the stars works.
But, as in any engine, the fuel is not infinite. At senescence, the Sun will run out of hydrogen reserves, so it will have to start fusing helium atoms in its place. When this happens, such a physical reaction will provide you with more energy, which will cause the Sun to begin to overheat to hundreds of millions of degrees Celsius, and also to expand. The stars are the only thing that heats up before cooling down , giving way to a red giant .
The red giants, then, are stars in the throes of death. During its transformation, the Sun will increase in size. So much so that it will reach the orbits of Mercury, Venus, and probably Earth. Our star king, who gives life, also distributes death, since it will literally swallow a good part of the rocky inner planets.
In its last breath, the Sun will shed its outer layers, but it will not explode as a supernova. There is scientific consensus that the Sun is not big enough to star in this spectacular finale, typical of stars of a much larger size. If this were the case, probably the complex chemical elements left behind by this explosion would end up forming a new star and new planets, as scientists actually believe happened at the birth of the solar system.
But, in the end, gravity will cause the Sun to collapse in on itself, to give rise to nothing more than a small core the size of Earth, a white dwarf; a mere cold corpse of the once powerful star that is still our star.
What will happen to the Earth?
We have already mentioned how the ancient Sun, turned red giant, is likely to expand so much as to reach Earth’s orbit, but it is not clear whether the outer layers of the Sun will eventually ‘swallow’ our planet , disintegrating into its inside; Another possibility is that it shifts its orbit as the size of the Sun increases. Finally, if the Earth were to survive the agony of our star, it is possible that the orbit would unravel, until our home would be adrift through space like an inert body; or else the orbits of rocky planets become so chaotic that they can collide with each other.
In 2009, astronomers from the Paris Observatory published in the journal Nature that the Earth could end its existence by colliding with Mercury, Mars or Venus; or that Mercury and Venus merge into a single ‘superplanet’.
Of course, long before this happens, the Earth will have ceased to be compatible with life , due to the unbearable climate that would be produced by the increase in size of our Sun. The oceans will evaporate and the rock will melt. Our planet, today a green and blue orchard teeming with life, could be reduced to what it was at its birth: a sea of lava covered in a toxic atmosphere.
As for the human being, five billion years is an eternity compared to the very short history of civilization. Many scientists, especially the most visionary, work with the idea that humans must leave Earth, long before it is no longer habitable. Famous geniuses like Stephen Hawking already noticed. For a few hundred years, we may have the technology to leave our planetary home and colonize new spaces in the solar system, or outside of it. In any case, by the time the Sun dies, the human being could be extinct a long time ago, and even other creatures that would have dominated the Earth later.
And the rest of the planets and moons?
The dire news of the disappearance of our Sun could be welcomed by other bodies in the solar system, at least for a limited time. The growth in size of our star in its transformation to a red giant would imply that the habitable zone would shift . Although the Earth would then be too close to the star to be compatible with life, other rocky bodies in the solar system could begin to be, as occurs with some moons of Saturn and Jupiter, today too cold to host life as it is. we know.
