According to NASA, the Sun will increase in size by at least 200 times
Most stars in the Universe are known as main sequence stars, those that convert hydrogen into helium in their cores through nuclear fusion. It is this reaction that fuels their energy and leads to their enormous growth throughout their lives: They can reach the size of the Sun a thousand times..
Throughout their “normal” lives, the external fusion pressure within main sequence stars balances the internal gravitational pressure. However, once nuclear synthesis stops, Gravity takes control and begins to compress the star.
“This increases the star’s internal temperature and ignites a layer of hydrogen that burns around the inert core,” notes the explanatory study of stellar evolution. Meanwhile, the helium core continues to contract and increase its temperature, resulting in a higher rate of energy generation in the hydrogen shell. This causes the star to expand significantly and increase its luminositybecoming a red giant.”
The red giant is dying star in the final stages of stellar evolution. According to NASA, in about five billion years, our Sun will become a red giant, expanding and consuming inner planets, including Earth.
When it expands Its outer layers will engulf Mercury and Venus and also reach Earth. Scientists are still debating whether our planet will be swallowed up or orbit dangerously close to the red giant sun. Either way, life as we know it on Earth will cease to exist.
However, this could be good news for other planets beyond Mars. When a star becomes a red giant, it changes the “habitable zone” of its parent system – the range of orbital distances in which liquid water can exist on the surface of the world. Because the star remains red giant, about a billion years oldIt is possible that life will emerge on distant planets and moons that will eventually receive some heat.
“When a star ages and burns, the habitable zone moves outward, and you essentially give the planetary system a second wind,” explains exoplanet scientist Ramses M. Ramirez, a researcher at the Carl Sagan Institute at Cornell University. Currently, objects in these outer regions are frozen in our Solar System. such as Europa and Enceladus, the moons orbiting Jupiter and Saturn.”