Scientists have discovered when and how our sun will die, and it will be epic : ScienceAlert
What will our Sun look like after it dies? Scientists have made predictions about what the last days of our solar system will look like and when it will happen. And we humans will not be there to see the solar curtain.
Previously, astronomers thought the Sun would turn into a planetary nebula – a glowing bubble of gas and cosmic dust – until evidence suggested it would have to be something more massive.
An international team of astronomers turned it around again in 2018 and found that the planetary nebula is indeed the most likely solar corpse.
The Sun is about 4.6 billion years old – measured based on the age of other objects in the Solar System that formed around the same time. Based on observations of other stars, astronomers predict that it will reach the end of its life in about 10 billion years.
Of course, there are other things that will happen along the way. In about 5 billion years, the Sun should turn into a red giant. The star’s core will shrink, but its outer layers will expand to orbit mars, engulfing our planet in the process. If it’s still there.
One thing is certain: by then we will be gone. In fact, humanity only has about a billion years left unless we find a way out of this rock. This is because the brightness of the Sun increases by approx 10 percent every billion years.
That doesn’t sound like much, but that increase in brightness will end life on Earth. Our oceans will evaporate and the surface will become too hot for water to form. We’ll be about as long as you can get.
It is what comes after the red giant that has proven difficult to pin down. A few previous ones studies have found yes, in order to light to form a planetary nebulathe starting star must be up to twice as massive as the Sun.
However, a 2018 study used computer modeling to determine that our Sun, like 90 percent of other stars, will most likely shrink from a red giant to become a white dwarf and then end up as a planetary nebula.
“When a star dies, it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be up to half the star’s mass. This exposes the star’s core, which until this point in the star’s life runs without fuel, eventually shuts down and before finally dying,” explained astrophysicist Albert Zijlstra from the University of Manchester in Great Britain, one of the authors of the paper.
“Only then does the hot core make the ejected mantle glow for about 10,000 years – a short period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light-years, where alone the star was too faint to be seen.”
The data model the team created actually predicts the life cycle of different types of stars, to reveal the brightness of the planetary nebula associated with different star masses.
Planetary nebulae are relatively common throughout the visible universe, and are known as the Helix Nebula, the Cat’s Eye Nebula, the Ring Nebula, and the Bubble Nebula.
They are called planetary nebulae not because they actually have anything to do with planets, but because they were first discovered by William Herschel in the late 18th century. similar in appearance to planets through the telescopes of that time.
Almost 30 years ago, astronomers noticed something unusual: all the brightest planetary nebulae in other galaxies have about the same brightness level. This means that, at least theoretically, by looking at planetary nebulae in other galaxies, astronomers can calculate how far away they are.
The data showed this to be true, but the models contradicted it, which has troubled scientists ever since it was discovered.
“Old, low-mass stars should produce much fainter planetary nebulae than young, more massive stars. This has become a source of contention over the past 25 years,” he said Zijlstra
“The data said you could get bright planetary nebulae from stars as low as the Sun, the models said it wasn’t possible, anything less than twice the mass of the Sun would give a planetary nebula too faint to see.”
The 2018 models solved this problem by showing that the Sun is roughly the lower mass limit for a star capable of producing a visible nebula.
Even a star with a mass less than 1.1 times that of the Sun will not produce a visible nebula. On the other hand, larger stars up to 3 times the mass of the Sun will produce brighter nebulae.
For all other stars in between, the predicted luminosity is very close to the observed one.
“This is a nice result,” Zijlstra he said. “Not only do we now have a way to measure the presence of billion-year-old stars in distant galaxies, a range that is extremely difficult to measure, but we’ve even discovered what the Sun will do when it dies! “
The research was published in the journal Natural astronomy.
An earlier version of this article was first published in May 2018.
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