> Árpád Szendrei asked: *"Can I really see what is on the opposite side of a black hole?"*

Yes. Let's take [this][1] 360°x180° full panorama:

[![enter image description here][2]][1]

Now we zoom in one direction:

[![enter image description here][5]][5]

and place a black hole in front of the observer:

[![enter image description here][6]][6]

Now we turn around by 180°:

[![enter image description here][3]][3]

and move the black hole into our new line of sight:

[![enter image description here][4]][4]

Here we look up 45° into the clouds:

[![enter image description here][7]][7]

and move the black hole into our view again:

[![enter image description here][8]][8]

As you can see we would see what's behind of us lensed around the black hole's shadow, but it would be strongly distorted.

The zoomed in images have a FOV of 103°x61°, the black hole has a spin of a=M. We only consider the black hole's gravitational lensing, not its destructive effects on the enviroment.

There's also a video [here][9] with the image used above, but the resolution is rather low. [This][10] video has a different background image, but higher resolution.

Since you tagged your question with "electromagnetism" as well you can also look at charged black holes [here][11]. You also tagged "quantum-mechanics", but this tag doesn't belong here in my opinion since the gravitational lensing is a GR, not a QM effect.


  [1]: https://commons.wikimedia.org/wiki/File:Afterglow_of_a_sunset.jpg
  [2]: https://i.sstatic.net/MaOkK.jpg
  [3]: https://i.sstatic.net/G8RlA.jpg
  [4]: https://i.sstatic.net/xoDEC.jpg
  [5]: https://i.sstatic.net/Yn66W.jpg
  [6]: https://i.sstatic.net/zKMvl.jpg
  [7]: https://i.sstatic.net/7jxk7.jpg
  [8]: https://i.sstatic.net/ZMeAi.jpg
  [9]: https://www.youtube.com/watch?v=8cREi-sjN_c
  [10]: https://www.youtube.com/watch?v=54aHbkG8Msg
  [11]: http://notizblock.yukterez.net/viewtopic.php?t=88