When and how will our star die? What will the Sun be like after his death? Astronomers have recently made new predictions about the planned end of our solar system.
The Sun is about 4.6 billion years old and according to the observations of other stars, astronomers predict that it will reach the end of its life in about 10 billion years. But what will happen along the way, exactly? In about 5 billion years, our star should become a red giant. Its core will shrink, but its outer layers will extend to the orbit of Mars, engulfing our planet in the process. One thing is certain: at that moment, we will certainly not be here anymore.
If we only base ourselves on the Sun, Humanity has only one billion years left before it goes extinct. By then – and if humans have not self-destroyed — we will have had time to colonize other worlds. In a billion years or so and according to the predictions, our star will be 10% brighter. This does not seem huge, but this increase in brightness will be enough to end all life on Earth. Our oceans will evaporate and the surface will become too hot for water to exist on the blue planet.
Scientists have agreed that the Sun should die in about 10 billion years, but they were not sure what would happen next, until now. A team of astronomers predicts that our star will turn into a massive, luminous ring of gas and interstellar dust known as the planetary nebula. It is so named because formerly astronomers took these phenomena for planets. A planetary nebula marks the end of 90% of stars. But for years, scientists were not sure that the Sun would follow the same fate: it was not thought massive enough to create a visible planetary nebula.
The team relied on computer modeling to finally determine that, like 90% of other stars, our Sun is more likely to end its days in the planetary nebula. “When a star dies, it ejects into space a mass of gas and dust that can reach half the mass of the star, which reveals the core of the star,” says astrophysicist Albert Zijlstra , from the University of Manchester in the United Kingdom. “It’s only then that the hot core shines the envelope ejected for about 10,000 years – a brief period in astronomy – which makes the planetary nebula visible.”
The data model created by the team actually predicts the life cycle of different types of stars, in order to determine the brightness of the planetary nebula associated with different star masses. It would seem here that, contrary to what was previously thought, the mass of the Sun marks the lower limit for a star to produce a visible nebula. Even a star whose mass is less than 1.1 times that of the Sun will not produce a visible nebula, astronomers note. Larger stars – up to three times more massive than the Sun – will produce the brightest nebulae.