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An international community Astronomers have found evidence that the universe changes again black holescombine them to make bigger ones. Gravitational waves records in recent years show that some of the most massive black holes in galaxies show clear signs of being “second-generation” black holes—things that collided in the past—and thus could not have come from the collapse of a massive star.
Impossible Black Holes
The theory of stellar evolution explains that, at the end of the life of the most massive stars, their cores compress into a knot so dense that it bends space-time to infinity. This is the black hole, which has 10 to 40 times the mass of the sun. There are also very large black holes, between galaxies, with millions or billions of suns, whose origin is related to processes that happened in the most ancient times of the universe.
Between these two categories there is a contested group: black holes with masses between 40 and 100 solar masses. They are too rich to be born after the death of a star, but they do not reach the dimensions necessary to emerge from the collapse of a large cloud of matter. Conventional stellar physics regards them as “impossible,” yet they appear frequently in detection.
Astronomers say that these supermassive black holes may have formed from the merger of two or more small, supermassive objects. The idea was sound, but it needed proof. Until recently, there was no way to get it.
Then gravitational wave detectors came on the scene. These instruments use lasers to measure the slow perturbations of spacetime caused by collisions of dense matter. The first detection, in 2015, confirmed the merger between black holes. Since then, each new indicator has allowed this pattern to become more visible and revealed that these collisions occur more frequently than previously thought.
Second Generation Signature
The study, published this month in Nature Astronomyanalyzed the time series of gravitational waves produced by three of the world’s leading observatories. The download included 153 reliable observations of black hole mergers. Of them, 34 correspond to very heavy objects.
By comparing all the signs, the team found two different people. Lighter black holes, up to about 40 solar masses, showed small, coherent spins, as expected for material born from the collapse of stars. But from another point, around 45 times the mass of the sun, a very different number appeared: super-massive black holes, rotating rapidly and in chaotic ways – a signature of figures that are possible only if the object has already existed in a previous union.
“This is exactly the signature you would expect if black holes repeatedly merge into galaxies,” said Isobel M. Romero-Shaw, co-author of the study. words from Cardiff University.
Until now researchers have not directly observed “impossible” black holes. It is not visible in X-ray or visible light, unlike the giants. However, their collisions vibrate with spacetime, and those vibrations reveal many phenomena that stellar physics cannot explain.
The research shows that supermassive black holes are built rather than born. They come from previous generations of collisions, which are collected in the densest regions of the cosmos.
This article appeared first WIRED in Spanish and translated from Spanish.
