It seems it is not possible to form black holes out of light alone. If energy and mass are one and the same, as Albert Einstein’s theories posit, then it should be possible to create a region of light so dense it collapses into a black hole – but a closer look has demonstrated quantum effects prevent that from happening.
The idea of a black hole formed by the collapse of light, called a kugelblitz, has been around for decades, with researchers considering everything from how to make them…