All along, stars symbolize the ancients’ eternal expectation and hope for them. But modern scientists tell us that there is nothing permanent in the world. There is a saying that “if there is love in the sky, the sky will grow old”. Stars, like human beings, will experience birth, aging, illness and death in a long time. But it has a long life, spanning millions to tens of billions of years. Many scientists were shocked by the sudden disappearance of a star 100 times the size of the sun 75 million light-years away, according to a study published in the monthly journal of the Royal Astronomical Society.
According to the news, the suddenly disappeared star is a very unstable giant white dwarf, phl293b, which is located in the Kingman dwarf galaxy of Aquarius, about 75 million light-years away from the earth. Because of the distance, we can’t observe it directly. But astronomers can detect the signal it’s sending to the Milky way. From 2001 to 2011, based on the changes of spectral and brightness data, scientists speculated that it was 250 times brighter than the sun, and about 100 times larger than the sun. It was a white dwarf after the evolution cycle.
Although white dwarfs are not stable, they still leave special traces for scientists to recognize. But Andrew Allan, an astronomer at the University of Dublin in Ireland, found that the light belonging to phl293b had disappeared when he re observed the star with a super large telescope in Chile in August 2019, which made them wonder if something had happened to the star.
We are shocked to find that this star has disappeared, and it is a very rare phenomenon that such a huge star has disappeared without producing a bright supernova explosion, Allen said.
After that, the team used various instruments from the European Southern Observatory, including four 26 foot telescopes, to observe stars at the same time. In addition, the team also combined the data analysis of Atacama large millimeter wave and other observatories in the past. They believe that the white dwarf may have experienced a strong explosion some time after 2011. So the team came up with two conjectures: first, the star was covered with huge dust during its aging; second, the star had died and might collapse directly into a black hole, so there was no supernova explosion.
Moreover, for the sudden disappearance of “phl293b”, some astronomy enthusiasts also said that they were taken in by aliens, based on the “Dyson sphere theory”. In the 1960s, Freeman Dyson, an American physicist, speculated that those advanced alien civilizations eager for huge energy would build a “Dyson sphere” device to collect energy and then directly wrap stars like the sun. Meanwhile, in the past half century, scientists have discovered 100 mysteriously disappeared stars for unknown reasons. Is this a masterpiece of aliens? However, this argument is not convincing.
In the modern stellar evolution theory, white dwarf is a special compact object, which is formed by the collapse of its core after the star runs out of fuel. The average white dwarf has about half the mass of the sun, slightly larger than the earth. So far, scientists have discovered more than 1000 white dwarfs, among which Sirius B is the first star discovered by human beings, twice the diameter of the earth.
Other scientists have calculated that our sun will slowly evolve into a red giant in about 5 billion years, and its volume will expand 200 times, then engulf mercury, Venus and earth, and finally become a white dwarf. After the sun becomes a white dwarf, its radius is about 5000 kilometers, smaller than the earth. Because most white dwarfs produce carbon during their evolution, carbon shows the most compact diamond structure under the action of gravity and high pressure. If human beings still existed at that time, maybe they could go to the sun to dig diamonds.