I'm busy with work today, and I'm going on a business trip tomorrow, so I ask for a day off and ask for your understanding.

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Peripheral information: [Shocking reversal: how a black hole can become a quasar]

Without a comprehensive understanding, it is indeed difficult to connect black holes with quasars. How did a black hole, which can swallow everything, become the brightest object in the universe?

The first thing to know about quasars is to know. Quasars are a very interesting celestial body. It is a bright point radio source that was discovered only after the advent of radio astronomy, but at the time of its discovery, it was not known what they were.

Quasars are usually only observed in the radio band. Because they only emit radio waves, they are called "quasar radio sources", or "quasars" for short.

Subsequently, quasars were found to have some common characteristics: extremely distant, with a large redshift; Extremely bright in the radio band means that some high-energy event is happening there; The difference in spatial orientation will cause them to behave differently.

Improvements in the means of observation have led to similarities between quasars and between quasars and certain other types of objects, such as active galactic nuclei, flare stars and magnetos.

As a result, it was recognized that the same high-energy event was happening on these objects: a supermassive black hole at the center of the galaxy was continuing to swallow food mass, while at the same time projecting a staggering amount of matter and energy outward, and releasing intense radio waves.

With further improvements, it is finally possible to see the host galaxies of these quasars, even if they are billions of light-years away.

But how is this possible? How can a black hole release such a huge amount of energy? Aren't black holes supposed to devour everything?

Yes, black holes do have the ability to devour everything, but that's not the case.

In fact, as long as we move away from the horizon of black holes, black holes are just ordinary sources of gravity. If we put a black hole with the same mass as the Sun in the position of the Sun, the movement of the Earth and other planets in the solar system will not be affected in the slightest.

Quasars behave this way because the speed of the matter around them is accelerated very quickly under the influence of the huge mass of the black hole.

Cygnus A on four different radio bands

This material forms a sucker around the black hole, which travels at extremely high speeds and produces radiation in various wavelength bands – including radio waves.

In both directions perpendicular to the accumulation cup, we can also see a pair of petal-shaped jets of relativistic velocity matter. If the direction of the jet is facing the Earth, it is called a flare; If not, it's another type of active galaxy.

The reason quasars are so bright is that the matter will be reduced to powder in the suction cup under the great gravitational pull. The shattered matter becomes extremely hot when it interacts and emits radiation.

They are extremely distant, but they can still be seen because they are supermassive black holes with hundreds of millions or even billions of solar masses, which devour millions of times the mass of the sun, while at the same time, thousands or even hundreds of millions of times the mass of the sun are thrown back into space in various forms.

So, the black hole is not a vacuum cleaner, but a sloppy and wasteful foodie.