Although it is estimated that our fireball of gas will become extinct trillions of years in the future, there will be many changes that will occur much sooner, heralding the end of our solar system. Scientists estimate that the «life» of the Sun in its current stage, known as its «main sequence», will end about five billion years from now.
At its current stage, nuclear fusion of hydrogen within the Sun allows it to radiate energy and provides enough pressure to prevent the star from collapsing under its own mass.
«The Sun is just under five billion years old,» astrophysicist Paulo Testa told Live Science.
«It’s a kind of middle-aged star, meaning its life will be in the order of 10 billion years or so.»
Mr. Testa is an astrophysicist at the Center for Astrophysics, a collaboration between the Smithsonian Astrophysical Observatory and Harvard College Observatory.
According to NASA: «In general, the older a star, the shorter its lifespan, although all stars, except for the most massive stars, live for billions of years.»
After the sun has burned up most of the hydrogen in its core, it will move on to its next stage as a red giant.
“After being deprived of producing the energy needed to support it, the core begins to collapse in on itself and becomes hotter.
Hydrogen is still available outside the core, so hydrogen fusion continues in an envelope surrounding the core.
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Doing so was difficult before they learned how to take into account nuclear fusion in solar masses.
«A lot of science is relatively new, as in the last century, because an integral part of understanding how a star works comes from understanding nuclear reactions and fusion,» said Mr. Testa.
“Before the 1930s, one of the main ideas of how stars work was that energy came only from gravitational energy.
«By collecting a lot of different information from many different stars, astronomers and astrophysicists can build a model of how stars evolve,»
«This gives us a fairly accurate estimate of the age of the Sun.»
These techniques allow scientists to accurately determine when our sun collapses in on itself.