2
$\begingroup$

Whenever there is a picture of a black hole, (even though they are artist depictions, this is how they are described) most are shown kind of in a flat disk like this. enter image description here

My question is, why do we see the black hole itself? If it is sucking in material from all directions, then shouldn't the material be kind of covering the black hole, not just spinning around it to be sucked in from only the sides. Especially in the case that a star would be sucked in, then wouldn't all of its light & matter in the accretion disk be encasing the black hole? In other words, why is the accretion disk flat, and not a sphere surrounding the black hole? So if this were true, we shouldn't be able to see some black holes, only their accretion disks around them.

(unrevised/old post: If a black hole is spherical and has infinite density, then it would be sucking in objects from all directions because the gravity would be the same all around. In other words, the event horizon should be all around it!

I understand everything would orbit the black hole a little before 'falling in', but since the amount of matter and light is so large, shouldn't it encase the black hole, thus making it covered in a ball of light? The event horizon would be a shell so we could not see some black holes, which would mean there could be billions more out there.

As for the other black holes which we have seen/proven, if the information above is true, then maybe they are the result of black holes with poles with low force/gravity/magnetivity/energy. Possibly they could be a disk of some sort or have an unequal distribution of density, either of which could lead to the flat event horizon, maybe even both.

Poles on a black hole would also help account for the quasars shooting out of some. Since the gravitational pull would not be as great from the poles of a black hole, then this would allow the quasars to beam out (otherwise they would have to be going faster than the escape velocity, which is the speed of light).

Maybe the quasars are even the black holes that I was talking about earlier, and this is why you would see no event horizon, only a shell of bright light.

I am no expert in astronomy but if any of these theories sound plausible, please let me know! Just looking for some explanation, I thought of this earlier and couldn't figure it out, I could be completely wrong though. Thanks!)

$\endgroup$
  • 2
    $\begingroup$ Can you rephrase this to ask a single specific and clear question? The question posed in the title doesn't seem to be in the body of the post. $\endgroup$ – James K Feb 1 at 20:59
  • $\begingroup$ Yep sorry I was having trouble figuring out how to put it! $\endgroup$ – Kimberly Bailey Feb 2 at 1:55
  • 1
    $\begingroup$ Hi Kimberly, welcome to Astronomy. Your question "why do we see the black hole itself?" is impossible to answer, as it's based on an incorrect assumption. Can you give an example of where we "see" a black hole? I'm not aware of any. We detect black holes by inference: stellar orbits, intense radiation from an accretion disk, gravitational waves, etc. Artists' impressions are simply that: impressions, not real observation. Wikipedia is a good start for a better understanding. :-) $\endgroup$ – Chappo Feb 2 at 4:33
  • 1
    $\begingroup$ Perhaps your real question is about the shape of the accretion disk. In fact there's already exactly that question on our site - see Accretion disks - why are they disk-shaped, rather than spherical?. $\endgroup$ – Chappo Feb 2 at 4:40
  • $\begingroup$ I'm voting to close this question as off-topic because it's not based on real science, as it assumes we can "see" the black hole itself. $\endgroup$ – Chappo Feb 2 at 4:45
2
$\begingroup$

Well it doesn't exactly work the way you describe it. Matter doesn't just fall into a black hole.

A black hole still has a finite mass, which means other matter orbits its just like it would a comparable object of the same mass, like a star. In fact the gravitational disturbance it causes in this way is usually how we determine that there are, for example, supermassive blackholes in the center of galaxies.

Now the light you speak of is an accretion disk. When a star orbits a black hole, the star can get torn apart due to gravitational variation in the star as a consequence of the nearby black hole. Matter from the star starts orbiting the black hole, but it cant just do that in any direction. Due to conservation of angular momentum (the star itself was rotating) it is forced to rotate in one specific circular path, thats what we call the accretion disk and is the reason it doesn't become a huge sphere of light. As for light itself, it can't orbit, it either gets deflected or it gets trapped inside.

$\endgroup$
  • $\begingroup$ Okay! Yes, that I can understand thank you! The thing I don't get is if the angular momentum of each star/object is different (and not all are, but most), wouldn't there be a whole bunch of varying orbits around the black hole, not just the flat accretion disk with pretty much the same orbits? Also, yes you are correct light does not orbit sorry I did not mean to say that. I was kinda trying to decribe gravitational lensing but couldn't remember the word. thanks! $\endgroup$ – Kimberly Bailey Feb 2 at 2:14
  • $\begingroup$ @Kimberly But light can orbit a black hole, in the photon sphere, although as that article mentions, those orbits are rarely stable. And of course the photons in the photon sphere aren't visible to observers outside the photon sphere. $\endgroup$ – PM 2Ring Feb 2 at 8:11
  • $\begingroup$ @Kimberly Bailey Ah I see what you mean. The answer is that space is actually really empty. For an accretion disk to form a star had to orbit and thus be in its neighbourhood. To give you a bit of a perspective: when our galaxy collides with andromeda, chances are pretty high that no stars will collide at all, just because the distances between them are so immensly vast. The accretion disk dissapears before there is even a chance for a second one to appear. $\endgroup$ – Jeroen Feb 2 at 8:41
  • $\begingroup$ ^^ Oh wow, that is very interesting I did not know that!! $\endgroup$ – Kimberly Bailey Feb 3 at 3:06
  • 1
    $\begingroup$ Okay, that makes sense! So really, the chances of even one star oribiting a black hole are pretty low, and multiple objects/stars is close to none? That would explain a lot, thanks for all the information and help! $\endgroup$ – Kimberly Bailey Feb 3 at 3:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.