what is blackhole horizon be like?

[lanzu]

On the 22nd of May in 2022, EHT released a photo of SgrA*, it's about the black hole horizon of the Milky Way , in this photo , we can see the event horizon of SgrA* and this is the first time we see the true face of this big monster.It is also our second time photograph the blackhole's face.By comparsion，we found that this image is very similar to the last one.With this observation,we probably can prove that almost all the galaxies have supermassive blackholes at their centers.It seems that black hole shadows all appear to be circular.Hope someone can continue talk with me.It's my pleasure.

 

[Helio]

What you're seeing is a highly processed image, which is described in detail here.

The better evidence might be the video that shows very rapid orbiting speeds for the stars that are in orbit around it.

Due to all the dust and gas between us and Sgr. A, we can't actually see any visual image of it, but we can "see" it at larger wavelengths.

 

[billslugg]

The Black Hole is a tiny invisible dot at the center of the picture. What we are seeing is the heat being emitted by the accretion disc surrounding the Black Hole.

 

[Helio]

What we are seeing is the heat being emitted by the accretion disc surrounding the Black Hole.

That makes sense but the image looks like this disk is more spherical than I would expect. Are we just lucky to be aligned to see a more face-on disk?

 

[Absolute zero]

My guess is we are seeing some form of gravitational lensing, perhaps of a near by gas cloud? I think the chances of us seeing a face-on disk to be pretty small but not impossible.

 

[billslugg]

As unlikely as it is, we are seeing this disc head on. The picture is fuzzy because the object has no distinct edges, it is a cloud of gas.

 

[Unclear Engineer]

For visualizing what General Relativity indicates about things close to a black hole, this link provides some very good discussion enhanced by video illustrations: https://jila.colorado.edu/~ajsh/bh/schw.html