Will the sun one day destroy the earth?

By Jonathan O’Callaghan/The New York Times

In 6 billion years, sun It will expand until it becomes a red giant. This process should consume Mercury and possibly Venus. We have long believed that this is also possible Burn the earth.

But perhaps all is not lost for him. Planet Earth (Although it may have become uninhabitable long ago.)

Scientists have discovered a rocky world orbiting another star that has already passed the red giant stage. This planet now orbits a white dwarf, the smallest stellar object remaining after the star exits. Remarkably, the planet appears to orbit the star in the same position that Earth currently moves around our sun, and it did so until it was pushed into a farther orbit, twice the distance between Earth and the sun, before the dying giant could devour it. . This makes it the first possible rocky world observed orbiting a white dwarf.

“We don’t know if the Earth can survive.”“If that were the case, it would end up somewhere like this system,” said Qiming Zhang, an astrophysicist at the University of California, San Diego, who led the study published in the journal Nature Astronomy.

The planet is about 4 thousand light years away from us. It was discovered in 2020 using a network of Korean telescopes through a process called microlensing. The Korean team had observed how the planet’s star passes in front of another star, which from the background increased the amount of light directed to the telescope a thousand times.

This event was a one-time event, limiting the possibility of follow-up detailed observations until new powerful telescopes can better observe the planet’s star in the future. But Chang’s team worked at the Keck Observatory in Hawaii last year and was able to identify it as a white dwarf. The data that the researchers were able to collect allowed them to calculate the presence of at least two objects orbiting the white dwarf.

One was a suspected brown dwarf, a failed star that never ignited by nuclear fusion, located at a great distance from the star. But the other object was a planet about 1.9 times Earth’s mass orbiting close to the star, suggesting it was a rocky planet.

By modeling evolution Star systemThe team calculated that the planet probably had the same habitable orbit as Earth. The star was probably also similar in size to our own.

But when the star ran out of fuel, it lost mass, causing the rocky planet’s orbit to elongate. This allowed it to escape the star’s expanding red giant stage and survive the white dwarf stage.

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