CNN Indonesia
Monday, 04 Dec 2023 09:42 IWST
Illustration. In about 5 billion years the Sun will die. (Photo: ESA)
Jakarta, CNN Indonesia —
In about 5 billion years, Sun will reach the end of its nuclear fuel burn time and will no longer be able to support itself against its own gravity. Then, could the Sun be black hole when it dies?
The outer layers of the Sun will spread out, and possibly destroy the Earth in the process, while its core collapses into something extremely dense, leaving behind a stellar remnant. If the gravitational collapse of the star’s core is complete, the remnants of the star will form a black hole.
A region of space and time with a gravitational influence so great that not even light can escape the Sun’s grip. So, will the Sun become a black hole when it dies?
In short, it can’t, because the Sun doesn’t have what it takes to become a black hole.
“It’s very simple: the Sun is not heavy enough to be a black hole,” said Xavier Calmet, a black hole expert and professor of physics at the University of Sussex, England, citing Live ScienceWednesday (6/9).
According to Calmet, there are several factors that can turn a star into a black hole, namely composition, rotation and the processes that regulate its evolution, but the main requirement is the right amount of mass.
“Stars with initial masses greater than about 20 to 25 times the mass of our Sun have the potential to experience the gravitational collapse necessary to form black holes,” he said.
This threshold, known as the Tolman-Oppenheimer-Volkoff limit, was first calculated by J. Robert Oppenheimer and his colleagues. Currently, scientists think a dying star must leave behind a stellar core that is somewhere around two to three times the mass of the Sun to create a black hole.
In theory, if the Sun’s mass were twice its current mass, the Sun would have the opportunity to become a black hole. However, this assumption turned out to be wrong.
When a star uses up nuclear fuel in its core, nuclear fusion of hydrogen into helium still occurs in its outer layers. So, when the core collapses, the outer layers expand from the star and it enters the red giant phase.
When the sun becomes a red giant in about 6 billion years, or a billion years after it runs out of hydrogen in its core, it will expand to around the orbit of Mars, swallowing the planets in orbit, perhaps including Earth.
The red giant’s outer layers would cool over time and spread out to form a planetary nebula around the Sun’s fiery core. Massive stars that create black holes go through several periods of collapse and expansion, losing more mass each time.
That’s because at such high pressures and heavyweight temperatures, stars can fuse heavier elements.
That lasts until the star’s core is made of iron, the heaviest element a star can create, and the star explodes in a supernova, losing even more of its mass.
According to NASA, typical stellar-mass black holes (the smallest variety astronomers have observed) are three to 10 times heavier than the Sun, but they can be up to 100 times that of the Sun.
A large, powerful stellar-mass black hole doesn’t start out this way, instead it gets heavier by feeding on nearby gas and dust, and even on the body of its companion star if it ever belongs to a binary system.
Calmet revealed the Sun, however, would never reach the iron-fuse stage. Instead, the Sun will become a white dwarf, a dense star about the size of Earth.
(rfi/dmi)
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2023-12-04 02:42:43
#Sun #Turn #Black #Hole #Dies
