Black holes are often represented as a 2D vortex in space. Isn't this wrong? Shouldn't it be a sphere?

Question

I know it makes good visual drama, but isn't the "space-dust bathtub effect" incorrect? A star in its lifetime is a sphere. When a star collapses into a black hole, wouldn't it naturally continue to be spherical? In that case, we wouldn't see the "space vortex". Wouldn't we just see a 3D nebula that gets progressively thicker towards its center?

Answer 1

You are correct. However, there is a difference in a rotating and non-rotating black hole.

A non-rotating black hole would be the equivalent of a spherical hole in space, and object entering it might not be destroyed. A rotating blak hole has tidal forces and due to its rotation, it exhibits a spiraling effect like material going down the drain.

Matter falling into this zone, however, tends to form a disc around the equator of the hole, where gravity is pulling it inward but heating effects are making it expand outward. This is called an accretion disc.

So because most black holes spin, they tend to have accretion discs around them, and these discs rotate something like material going down a drain, but would usually be glowing in x-rays and would appear smooth, not spiraled.

Answer 2

It wouldn't get thinker towards the center because when a star collapses the gravity is so great that it forms a singleton that is infinitely small. The reason that it is depicted as a vortex is because the mouth is the only part that exists in this dimension. Once something enters a black hole it mass collopses in what they therorize a funnel through space and time to the infinitely small point.

Answer 3

That representation is used because if you are watching things fall into a black hole, (most of which are rotating rapidly) then by virtue of radial velocity, outside the disk near the equator stuff does not fall in (much) but forms an 'accretion disk' , which you can picture as like the rings of Saturn - flat as anything, but wide.
Therefore, when you are looking at things falling into a black hole, you are watching from almost along the axis of rotation; things only a little off from that axis will spin, thus the swirling cone, however, they are all falling in, so you get a swriling cone falling rapidly into the black hole, as represented.

The black hole itself should remain unseen by definition, though.

Answer 4

Yes, you are correct.The visualizations you see in the movies and on TV are inaccurate in this way. On the other hand, in real black holes, there tends to be an accretion disk that represents where the matter is being drawn in, so some representations along this line are accurate.

Answer 5

A black hole should be a sphere because yes, the energy a black hole is exerting is sooo strong that it pulls everything together like crazy. It's like having a super gravity that not even light can escape. So technically we can't even represent a black hole because we can't see it.

Answer 6

really it sorta would be 4d because in the universe it is a depression or so in time and space as the universe is 3d it is hard to represent but using 2d space to show the universe and 3d to show the black hole. in other words, time and space are very confusing

Answer 7

Yes. You are right.
The common 2D space-time bathtub whirlpool
representation is simply because we use the third
visual dimension to represent time (the whirlpool).

Answer 8

Well............... scientists can't answer this exactly. Its too dark to see a blck hole because they swallow up light. But they think they are 2D thins that basicaly trap things and covers them up and breaks don thier molicules as they come closer. At least thats what I learned in astronomy.

Answer 9

It is because both the black hole and the star are rotating.

Answer 10

I would think you are right on the money. Special effects in movies is where we get the idea of the flat black hole.
Also, I don't think we would "see" one at all as light is drawn into them as well.