What is accretion of light? What is the collection of light?

Black holes are usually discovered because they gather around the gas to produce radiation, a process known as accretion. The efficiency of radiant heat energy from high-temperature gases can seriously affect the geometrical and kinetic properties of accretion flows. Thin disks with high radiation efficiency and thick disks with low radiation efficiency have been observed.

When accretion gases approach a black hole, the radiation they produce is extremely sensitive to the black hole's rotation and to the pure presence of the event horizon. Analysis of accretion black hole luminosity and spectroscopy provides strong evidence for the existence of rotating black holes and event horizons. Numerical simulations also show that accretion black holes often exhibit relativity, and that jets are partly driven by the black hole's rotation.

Astrophysicists use the word "accretion" to describe the flow of matter to a gravitational body or extended system of matter. Accretion is one of the most prevalent processes in astrophysics, and it is precisely because of accretion that many common structures around us are formed. In the early days of the universe, galaxies were formed when gas flowed towards the center of the gravitational potential well created by dark matter.

Even today, stars are formed by gas clouds that collapse and fragment under their own gravitational pull, and then accretion of surrounding gas. Planets – including Earth – are also formed around newly formed stars through the accumulation of gas and rocks. But when the object is a black hole, accretion shows its most spectacular side.

The netizens above have similar questions, but I have reservations about the answer.

1. First of all, does a black hole have spin? All observed black holes have spins, and the black holes themselves are not stationary, they are in constant motion.

2. After entering the gravitational event horizon of the black hole, does the matter fall into the center of the black hole in a straight line? Or is it spiraling and gradually accelerating into the center? It has to be the latter.

3. Let's talk about the problem of accretion disk. Here's a concept of "Eddington luminosity":

Eddington luminosity is the maximum luminosity that can be achieved by accretive objects. Celestial bodies emit radiation while accreting the surrounding medium, and when the accreted material accumulates to a certain extent, the radiation pressure prevents the material from falling further. At this point, the gravitational pull of a celestial body acting on a particle is in equilibrium with the radiation pressure it is subjected to, further indicating that the luminosity that can be achieved by the accretion of a celestial body is proportional to its own mass.

When it is lower than Eddington's luminosity, the transparency is low (opaque, blackness is higher), and the accretion disk material is relatively thin;

4. The accretion disk has the saying of "geometrically thin and optically thick", which means that in the vertical direction, the geometric size of the disk material is thinner, but the luminosity is higher.

Personally, I can only understand this, and the questions you ask have a certain professional depth, and it is estimated that only the astrophysics major can perfectly answer your questions, hoping to help you.

1. Not every black hole has an accretion disk, and only a rotating black hole must have an accretion disk, because the rotating black hole will drive the surrounding space to rotate together (because the black hole itself is a special structure of space), and the static black hole will not have the conditions for forming an accretion disk, and the matter will fall directly into the black hole;

And even if a black hole rotates, a large amount of foreign material must be introduced into the black hole's gravitational field to form an accretion disk, so not every rotating black hole can form an accretion disk.

2. The radius of a black hole is proportional to its mass, so the volume of a black hole is proportional to the cubic of mass.

3. It's hard to say, the reason is 1 there.

And then when it comes to density, since the volume of a black hole is proportional to the cubic of mass, then obviously, the heavier the black hole, the smaller the density, not the same.

Who said that light is not a stupid nuisance? Light has wave-particle binary disorder, that is, light can be regarded as a very high frequency electromagnetic wave, and light can also be regarded as a particle, that is, light quantum, referred to as photon.

When a beam of light is projected onto an object, it will cause reflection, refraction, interference, and diffraction. In this sense, it is a "wave."

But it is composed of tiny particles like "ping-pong balls" --- light quanta, so what is it called matter?

Due to the gravitational pull of the black hole, it sucks up photons. So the light was sucked in.

Black holes don't suck time, you can see for yourself what time is.

Yes, the event horizon of the black finger attack on the letter hole is the light that revolves around the black hole, and he can't escape and can't fall into the black hole to meditate blind. He is emitted light when the event horizon of the black hole is formed.

Light has no mass, and Newton's universal gravitational nucleus requires 2 substances with mass to attract each other, so the theory of relativity is used to explain black holes.

In the theory of relativity, the effect of gravitational attraction is defined as space-time distortion. The property of light is that it moves at the shortest distance, which we understand as moving in a straight line even if it is absolutely unavoidable. Because space is distorted, when light moves at the shortest distance, it takes a detour because of the distortion of space.

Image point said. If you think of the space around a black hole as a sheet of paper, the gravitational pull of the black hole bends the paper that is spread out of the hail.

It's like when we hold a rolled-up orange and point to a newspaper.

The light just ran along the curly piece of paper.

It can be said that the circle is orbiting around a black hole.

No, the path of light is a straight line. The properties of light are wave-particle duality, and so on. Boom.

If you want to know the clear point of clear liquid, you can check it on the Internet yourself. If you find something interesting, I hope you tell me. I'm also interested in that.

1. Closing the light can be explained separately, tightening is the meaning of tightening or pressing, compacting and tightening the cement mortar, reducing the gap of the cement mortar itself, reducing the possibility of cracking, light is the meaning of the smooth surface, to achieve brightness and smoothness, so it is also called calendering and tight light.

2. Before the initial setting of the concrete, the concrete surface is repeatedly rubbed with a trowel or a plastering machine. It can eliminate concrete surface defects and prevent the formation of plastic shrinkage cracks.

3. Collecting light is the last process of making a test block! Trim and compact! It's just that there are different sayings in different places, and there are many sayings in the construction industry.

4. Before the initial setting of concrete (mortar), after rubbing with a wooden trowel, it is calendered for the first time with an iron trowel; After the concrete (mortar) surface is watered (it is advisable for people to step on footprints, but not to fall into), calender for the second time, and use uniform force when calendering, compacting and calendering the surface, and removing surface bubbles, sand holes and other defects.

Focal length is a measure of the concentration or divergence of light in an optical system, which refers to the distance from the center of the lens to the focal point of light concentration when collimated light is incidentified.