"We developed a practical, simulation-backed way to compare images of the hot gas around black holes predicted by Einstein's general relativity with images predicted by deviation from general relativity," research lead author Akhil Uniyal of the Shanghai Jiao Tong University in China told Space.com. "Running realistic three-dimensional simulations of gas and magnetic fields for many hypothetical black-hole spacetimes produced synthetic images and defined image-comparison metrics that quantify how different two images are.
"The key result is that while many alternatives look very similar to the 'standard' black hole at today's image quality, the differences grow predictably as imaging resolution and fidelity improve, establishing that next-generation horizon-scale imaging could tell Einstein's black holes apart from non-Einstein black holes."