To this day I believe black holes remain a mostly theoretical phenomena. Which also happens to deal with infinity-mathematics in the singularity, something we don't see in reality otherwise.<p>Yes, observations have been made to their advantage, through LIGO and more recently the image from 2022 of a black hole made by the Event Horizon Telescope. But I would stress that the ""image"" is much more complex than simply a photo from really good ""telescope"", it's a image made of combined data from radio telescopes all around the world. There is enough weird hoops that they need jump through that the observation can reasonably be doubted in my opinion, which isn't to say that what they've attempted is awesome and inspiring.<p>Please correct me if you have other information.