Pinpointed how and when our Sun will die: it will be epic

Humans may already be gone, so they won't be able to witness the final act. Scientists have made predictions about how the solar system will shut down.

For years, people have been studying what the Sun might look like after it dies. An international team of astronomers has come up with a prediction of how our Solar System might end, but by the time that happens, humans should be gone. The study was published in 2018 in Nature Astronomy, and among the authors is Albert Zijlstra of the University of Manchester in the United Kingdom. Our star could turn into a planetary nebula, a bubble of gas and dust. This "death" had been theorized earlier and then refuted when other evidence suggested it should be a bit more massive.

Research into how and when the Sun will die

The 2018 International Analysis Team brought back the planetary nebula theory. The Sun is about 4.6 billion years old, and based on observations of other stars, astronomers predict it will "die" in about another 10 billion years. Already in about 5 billion years, our star will turn into a red giant. Its core will shrink, but its outer layers will expand toward the orbit of Mars, swallowing our planet in the process, should it still exist. The only thing that is certain, according to scientists, is that by that time life on Earth will have disappeared.

Humanity would only have about a billion years left because the Sun increases in brightness by nearly 10 percent every billion years. Our oceans will evaporate and the surface will become too hot for water to form. What remains difficult to define, however, is what will happen after the Sun becomes a red giant. The 2018 study used computer modeling to determine that, like 90 percent of other stars, our Sun is most likely to 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 mass of the star. The envelope will travel without fuel until it dies out before finally dying," explained astrophysicist Albert Zijlstra.

Just at this time the hot core will make the ejected envelope glow about 10,000 years earlier making the planetary nebula visible. "Some are so bright that they can be seen from extremely large distances," Zijlstra added, "measuring tens of millions of light years. The data model the team created actually predicts the life cycle of different types of stars to understand the brightness of the planetary nebula associated with different stellar masses. "Not only do we now have a way to measure the presence of stars a few billion years old in distant galaxies, but we've also discovered what the Sun will do when it dies!" concluded the astrophysicist from the University of Manchester.

Another team of scientists has instead discovered Sun 2, which could help predict the future of our star.

Stefania Bernardini