Question regarding black holes

[CWingfield]

I am having a hard time finding an answer to a question. So, I figured I would try the "scientific crowd-sourcing" route in hopes to find it.

 

The question is: Does the the draw or pull of matter/gas into a black hole fluctuate or does it pretty much remain static? I am not referring to the size of the black hole, but rather just the inflow of material into said black hole. Perhaps this question can only be answered using long term observation?

[Strange]

Good question. One answer is simple: yes, the gravitational pull is constant (apart from increasing slowly as it grows in mass).

 

The other answers is that it is more complicated. The amount of matter falling into the black hole is limited because as it starts to fall in, it is heated and can generate large amounts of pressure and radiation. This can slow, and eventually stop, the rate at which matter falls in. This can also generate the massive jets of matter and radiation from the poles.These processes are not fully understood, but it is thought that there is an upper limit to the rate at which black holes can grow.

A bit more here: https://en.wikipedia.org/wiki/Black_hole#Accretion_of_matter

[Phi for All]

The pull is constant, but the matter is changing, heating up as it nears the accretion disk, right? As it heats, it's gravitational energy changes as well, so while the pull is constant, it's pulling on matter that's changing rapidly as it's being pulled. That's the way I've understood it.

 

An earthly example that's not entirely dissimilar (maybe only in my mind) is a roasting marshmallow. The heat surrounding it in the fire is constant, but the marshmallow itself changes how the heat affects it. It starts out white and reflects a certain amount of the heat, but as it goes from white to burnt black, it reflects less and absorbs more.

[MigL]

Dormant BHs don't usually change much as they have a steady but very small influx of mass.

Active BHs are sometimes known as Quasars. They have a massive influx of mass, but a large portion of this influx is converted to energy as polar jets of radiation produced by the energetically rotating accretion disc. These active BHs can grow in size to millions of solar masses, and are present in the centers of galaxies, where the density is high enough to feed their voracious appetite.

[CWingfield]

Thank you all for your informative responses.

 

So, if I understand correctly, the pull is always the same. However, there is just so much matter a black hole can "process" at one time, therefore it will shoot the excess out one end or the other.

 

I apologize for the simplicity of that statement, I am just trying to wrap my head around it.

[Strange]

So, if I understand correctly, the pull is always the same. However, there is just so much matter a black hole can "process" at one time, therefore it will shoot the excess out one end or the other.

 

In very basic terms, that's about it. Although, I'm not sure it will always result in jets; it may be that a large amount of matter in the accretion disk just stops stuff reaching the black hole and blows the excess matter away, without forming jets.

[Sensei]

To really explain black hole formation there is needed quantum physics and general relativity unification..

[CWingfield]

Everyone did an excellent job keeping it simple enough for me to understand. I do realize there is much more to the black hole formation. However, these simple explanations can go a long way is helping at least understand the basics, as we currently know them.

 

It is too bad black holes aren't visually detectable, via Hubble or the like. That accretion disk must be something to behold. I would imagine it looking like a crashing wave with a constant undertow keeping it perpetually rolling in place.

 

Thank you all again for your information.