There is already an image of the black hole M87*. Now an international research team is solving a major mystery about the monster celestial body: Does it rotate?
HANGZHOU – In 2019, a stunning image of the black hole M87* suddenly revealed it. Astronomers have been able to image the shadow of a black hole for the first time using a technique called long-base interferometry (VLBI) and the Event Horizon Telescope (EHT). The image marked a milestone in astronomy, and was quickly followed by an image of the black hole at the center of our Milky Way Galaxy (SgrA*). But just because black holes can now be photographed doesn’t make them any less mysterious celestial objects.
|In the center of the galaxy M87|
|About 55 million light-years away|
|6.5 billion solar masses|
|60,000 light years away|
Kazuhiro Hada (National Astronomical Observatory of Japan) recalls: “After successfully imaging the black hole in this galaxy using EHT, the question of whether this black hole is rotating or not became the main concern of scientists.” If you follow Albert Einstein’s general theory of relativity, both options are possible: that supermassive black holes like M87* rotate, but they also do not rotate.
An international research team shows: black hole M87* is rotating
The biggest problem in the research: Direct observation of black holes is very difficult because they devour everything that comes close to them. Even the light that was absorbed by the black hole no longer comes out, so black holes are almost invisible. For this reason, the research was only able to show the black hole’s shadow and light from matter moving in the accretion disk around the black hole.
However, an international research team led by Chinese researcher Yuzhou Cui (Zhejiang Laboratory) has now apparently succeeded in detecting the rotation of the black hole M87*. “The prediction has become a certainty. This monstrous black hole is already rotating,” says researcher Hada happily. notice.
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Many years of observation are worth it: detecting black hole rotation
For 22 years, the research team has observed the M87* black hole using more than 20 radio telescopes around the world. This enabled the researchers to examine changes in the so-called jet in more detail. A jet is a huge stream of matter and energy thrown into space by a black hole.
Indeed: The research team found that the plane changes direction and oscillates back and forth on a cycle lasting approximately 11 years. In the study, the researchers showed that the movement of the jets is linked to the supermassive black hole – the rotating black hole M87*. “We are excited about this important finding,” says Cui, the study’s lead author. In the specialized magazine nature published had become.
However, the study cannot answer all questions related to the black hole. Until now, for example, it is still unclear how fast the black hole rotates around its axis, and what the structure of the accretion disk around the celestial body looks like. Further observations can also help answer these questions. (unpaid bill)
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