Scientists debate how the Sun will end its days. Some believe it will become a black hole, while others consider it to become a red dwarf. Now NASA has ruled on this eternal debate and has established its position: the Sun will not end its existence, like many other stars, becoming a black hole and not a neutron star.
According to an agency statement, our star would need to be approximately 20 times more massive to end its life as a black hole.
Stars that are born this size or larger can explode in a supernova at the end of their lives before collapsing again in a black hole, an object with a gravitational pull so strong that nothing, not even light, can escape.
Some smaller stars are large enough to become supernovae but too small to become black holes: they will collapse into super-dense structures called neutron stars after exploding like a supernova. But the Sun is not big enough for this destination either: it has only about a tenth of the mass needed to become a neutron star.
So what will happen to the sun? In about 6 billion years, it will end up as a white dwarf, a small, dense remnant of a star that shines from the excess heat. The process will begin in about 5,000 million years from now when the Sun begins to run out of fuel.
Like most stars, during the main phase of its life, the Sun creates energy by fusing hydrogen atoms in its nucleus. In about 5,000 million years, the Sun will begin to run out of hydrogen in its nucleus to merge and will begin to collapse. This will allow the Sun to begin to fuse heavier elements in the nucleus, along with the fusion of hydrogen in a shell wrapped around the nucleus.
When this happens, the temperature of the Sun will rise, and the outer layers of the Sun’s atmosphere will expand so much in space that they will engulf the Earth. This would make our planet unfit for life as we know it, although other factors in planetary evolution could make it uninhabitable before that point. This is the giant red phase, and it will last approximately one billion years before the Sun collapses to form a white dwarf.