Everything in this world will end. And according to the fashion of mathematics and astronomy for decades, this includes the Sun. So, when will the Sun explode and go out?
Although the final death of our mid-mass Sun is trillions of years in the future, the Sun's "life" is in its current phase, known as the "main sequence," in which nuclear fusion of hydrogen allows it to radiate energy and exert sufficient pressure to keep the star in motion. not collapse under its own mass, will end about 5 billion years from now.
"The sun is less than 5 billion years old. It's kind of a middle-aged star, in the sense that its life will be about 10 billion years or so," said Paola Testa, an astrophysicist at the Center for Astrophysics.
According to NASA, once the Sun has burned most of the hydrogen in its core, it will transition to its next phase as a red giant. At this point, about 5 billion years in the future, the Sun will stop generating heat through nuclear fusion, and its core will become unstable and contract.
Meanwhile, the outer part of the Sun that still contains hydrogen will expand, glowing red as it cools. This expansion will gradually engulf the Sun's neighboring planets Mercury and Venus, and push the solar winds to the point where they destroy Earth's magnetic field and release its atmosphere.
Of course, this would almost certainly be the apocalypse for any life remaining on our planet at that time, assuming any survived the 10% increase in the Sun's brightness.
According to a 2014 study published in Geophysical Research Letters, this 10% increase in the Sun's brightness is expected to vaporize Earth's oceans within 1 billion to 1.5 billion years.
And based on a 2008 study published in the Monthly Notices of the Royal Astronomical Society, within a few million years of this initial expansion, it's likely that the Sun will also eat up Earth's rock remains.
The sun will then begin to combine the helium left over from the hydrogen fusion into carbon and oxygen, before eventually collapsing into its core, leaving a beautiful planetary nebula (the remaining hot plasma shell) in its outer layers as it shrinks into an extremely dense Earth-sized "corpse" of stars, much hotter, which is known as a white dwarf.
The nebula will only be visible for about 10,000 years. From there, what's left of the Sun will take trillions of years to cool before eventually becoming an object that no longer emits light.
To arrive at this timeline, for the Sun and all stars with their relative masses, scientists needed to know how it emits energy, which is difficult before nuclear fusion in the Sun's mass can be accounted for.
"A lot of science is relatively new, like in the last century, because an integral part of understanding how stars work comes from understanding nuclear reactions and fusion," said Testa, who researches heating mechanisms and X-ray emission processes.
"Before the 1930s, one of the main ideas about how stars worked was that energy came only from gravitational energy," he continued.
Once astronomers and astrophysicists have a better understanding of fusion, they can produce a more complete model, supplemented by data on the observed emissions of some stars.
"By gathering a lot of different information from many different stars, astronomers and astrophysicists can build models of how stars evolve. This gives us a rather precise guess as to how old the sun is," explains Testa.
This age, about 4.6 billion to 4.7 billion years, is also corroborated by the radioactive dating of the oldest known meteorite, which formed from the same solar nebula, a rotating disk of gas and dust that gave rise to the sun and planetary bodies around the planet. solar system.
Thanks to this tool, scientists have a good understanding of when the Sun's light will eventually fade and go out.
